1984 Louisiana Loess Fieldtrip Guidebook

Loesses in Louisiana and at

Vicksbu rg# M iss iss ipp i by

1 2 3 1 B. j. Miller, G. C. Lewis, J. j . Alford, am VI. j. Day

Guidebook for the Friends of the Pleistocene Field Trip, APril 12, 13, am 14, 1984

Agronomy Dept. La. Agri. Exp. Sta. LSU Agricultural Center La. Stat e Univ. and A & M Baton Rouge, La.

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2. Dept. of Plant and Soil Uhiversity of I daho Moscow, Idaho

Sciences 3. Geography Dept.

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Western Il l onois Univ. Macomb, Illonois

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ACKNOWLEDGMENTS

It is unfortunate that any attempt to acknowledge all who in some way

have provided assistance in the studies of loess in Louisiana, the preparation

of this guidebook, and planning and coordination of the Field Trip is fraught

with omissions. We~ therefore, wish to express our thanks and appreciation

to all 'lTho gave ass is tance.

The contribution of Dr. Scott Burns at Louisiana Tech University has been

tremendous. Without his cooperation and efforts, the Field Trip would have

been next to impossible. We especially want to thank him for handling all

correspondence and coordination for the meeting. Similarily, Dr. Wayne Hudnall

in the LSU Agronomy Department has provided invaluable help in logistics for

the field trip and in coordinating access to sites. Others whose special

contribution is appreciated include Max Baer, K. L. Latiolais, B. A. Lindsay,

M. E. Sweeley, C. M. Corkern, and K. M. Curtis.

Special thanks are due to Ms. Dianne Beeson, Ms. Lisa Landry, Ms. Pamela

Latimer and Ms. Lorraine Crawford for cooperation, tolerance and special

efforts in typing and printing the guidebook.

The Field investigations have been conducted In conjunction with the Coop-

erative Soil Survey Program in Louisiana. The support, cooperation and assist

ance of the many soil scientists with the USDA-Soil Conservation Service is

especially appreciated. A partial listing of those involved includes R. B.

Daniels, B. A. Touchet, W. L. Cockerha~, E.T. Allen, B. J. Fleming, C. E. Martin,

P. G. Hartin, S. D. Matthews, D. R. McDaniel, C. T. Midkiff, L. Morris, K. E.

Murphy, B. E. Spicer, L. Trahan, D. F. Slusher, E. Reynolds, and T. A. Weems.

TABLF. OF CONTENTS

INTRODUCTION . ..•. 0 •••••••• It •••••••••• It It ••••••••••••••••• III a •••••••

LOESS IN LOUISIANA ..

Historical Overview. Lithology •.•.•••••.•. Source and Distribution Patterns •..•• Geographic and Landscape Settings .•• Basal Mixed Zones. Other Features •.••

Depth of leaching •. Color •.••••••••.. Pedogenic sands •. Buried soils ••

Stratigraphy ••.•• Twenty Questions .................. .

Page

1

1 3 3 9

fa 13 l3 13 14 14 14 19

Modern Soils Developed in the Loesses............................ 22

MATERIAL S AND METHODS ••..••••• It • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 28

FIELD TRIP SITES

Site 1.. Site 2 ••• Site 3 •• Site 4 •• Site 5 •• Site 6 ••• Site 7. Site R ••• Site 9 .•

• ••••••••••••• II' •••••••••••

REFERENCES • .•.. 0 • '" •• '" ••••••• e ••••••••••••••••••••••••••••••••••••

31 39 49 59 68 77 88 98

107

121

I

II

LIST OF FIGURES

Figure 1. Approximate location of completed transects in study of Loess in'

Louisiana ..................... ............................ III iii •• iii • iii .. • • 2

Figure 2. Approximate thickness and distribution of Pre-Peoria loess in Louisiana .... ~ . . . ... . . . . ... ... . . . . . . . .... . . . . . . . .. . .. . . . . .... . .. .. . . 4

Figure 3. Approximate thickness and distribution of Peoria loess in Louisiana .. 0 • • •• • ••• • • • • •• • •••• • • • ••• ••• • • • • • • • •• •• •• • •• • •••• • •• • • • • 5

Figure 4.' Approximate thickness and distribution of loess in Lo~isiana. • • • • • • • • • • • . • • • • • • . • • • • • • • • • • . • • • • • . • • • • . • • • • . • • . • • • • • • • . • 6

Figure 5. Clay-free particle size distribution in the silt-size fraction from two soils developed in Peoria loess in Louisiana ••••• -. • • • ••• . •• • • • • • 8

Figure 6. Thickness of loess and the zone of mixing in loess overlying sandy Coastal Plain deposits along an east-west transect in Southeastern Louisiana (Source: Spicer, 1969; Miller, B. J. unpublished data) ••• 11

Figure 7. Loess thickness and thickness of the zone of mixing along an east-west transect in Franklin Parish, Louisiana (Source: Rehage, 1980)........................................................... .. .. 12

Figure 8. Relationships among loesses identified and correlated at six locations in the Lower Mississippi Valley ••••••••••••••••••••••••••• 16

Figure 9. Clay-free particle size distribution (Coulter Counter and sieve) in a Memphis soil and underlying Paleosol on the Prairie Terrace in East Baten Rouge Parish, Louisiana .•....•.•..••.......•..•.•....•.•. 34

Figure 10. Clay-free particle size distribution (Coulter Counter and sieve) in an Olivier soil and underlying Paleosols on the Irene Terrace in East Baton Rouge Parish, Louisiana •••••.•••••••••••••••••••••••••••• 44

Figure 11. Loess thickness and distribution observed in an east-west transect in Lafayette Parish. Louisiana ••.•.•••.....•••....•......•...... ~... 50

Figure 12. Schematic of relationships between modern soils and loess thickness on the Prairie Terrace in the Lafayette-Crowley area in Louisiana ••. 51

Figure 13. Clay-free particle size distribution (Coulter Counter and sieve) in a Memphis soil and underlying Paleosol on the Prairie Terrace in Lafayette Parish, Louisiana .. 0 o. I) It 0 It.o.o ••••• o. CII ••••••••• 0." •• " I)" •• ". 54

F~gure 14. Alluvium-Loess - Terrace formation relationships in the vicinity of .Lafayette, Louisiana ................................ III •• " ••• II " • III • • • • • • 60

Figure 15. Clay-free particle size distribution (Coulter Counter and sieve) in a Baldwin soil unit inclusion and underlying Paleosols on the Hulocene Mississippi River alluvial plain in Lafayette Parish, Lou is ia na ........ •... III It eo " 0 • '" 0 e 0 eo 0 41 0 •• 0 • 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 It 0 0 0 0 0 I) " I) • B eo e 63

III

Figure 16. Clay-free particle size distribution (Coulter Counter and sieve) in a Duralde soil taxadjunct and underlying Paleosol on the Montgomery Terrace in Evangeline Parish, Louisiana............................. 72

Figure 17. Some relationships between sediments, landscapes, and modern soils in areas with thick loess deposits on the Macon Ridge in Louisiana •. 78·

Figure 18. Some relationships between sediments, landscapes. and modern soils in areas with moderately thick loess deposits on the Macon Ridge in Louisiana ... " ...... "............................................... 79

Figure 19. Some relationships between sediments, landscapes, and modern soils in areas with thin loess deposits on the Macon Ridge in Louisiana.. 80

Figure 20. Some relationships between sediments, landscapes, and modern soils in areas lacking identifiable loess deposits on the Macon Ridge in Louisiana ............. It 0 ............... OJ ........................ 3 8... 81

Figure 21. Distribution of loess and other sediments on an east-west transverse across the Macon Ridge from Louisiana Highway 4 bridge at the Boeuf River to vicinity of Old Church in Franklin Parish, Louisiana" .............. It 0 • • • •• • • • • • • • • •• •• • • • • • • • • • • • • • • • ... •• • • • • • • 82

Figure 22. Clay-free particle size distribution (Coulter Counter and sieve) in a Dexter soil on the Macon Ridge in Franklin Parish, Louisiana..... 85

Figure 23. General relationships among geologic materials in the Sicily Island Hills area in Louisiana ................................ " ...... eo. • • 89

Figure 24. Clay-free particle size distribution (Coulter Counter and sieve) in a Memphis soil and underlying Paleosols on Sicily Island in

Figure ')'" L-J.

Catahoula Parish, Louisiana........................................ 93

Soil-Landscape-Parent Material relationships in Morehouse Parish, Louis iana .. .. ijo .. w iii ...... ill .. 0;; G G .. " ;:; iii> $ ill ill ;; G G G ¢> Q Q ::> ::I ::> ::> e = eo eo e ::I ::I ::I = eo ::I = ., " e '" ., ., « O!) • ., • @I '" • 99

Figure 26. Clay-free particle size distribution (Coulter Counter and sieve) in a Memphis soil and underlying Paleosol on the Macon Ridge in Franklin Parish, Louisiana......................................... 102

Figure 27. Mississippi StandaI~ Loess Section showing approximate position of material dated by C and TL methods............................... 108

Figure 28. Clay-free Particle-size Distribution (Coulter Counter and Sieve) in a Memphis Soil and Underlying Paleosols in Vicksburg, Mississippi •. 112

IV

Table 1.

Table 2.

LIST OF TABLES

14 Significant C and Thermoluminesence Dates Relating to the Loess Stratigraphy in the Lower Mississippi Valley ••••••••••••••••••••••••

Major Soils Identified in Louisiana that Developed in Peoria Loess Deposits Thicker Than 1.25 to 1~50 meters •••••••••••••••••••••••••••

Table 3. Major Soils Identified in Louisiana that Developed in Peoria Loess Deposits Less Than 1.25 to 1.59 Meters Thick and Contain an Admixture

15

23

of the Underlying Material Throughout ••• ~........................... 24

Table 4. Major Soils Identified in Louisiana that Developed in Pre-Peoria Loess Deposits More Than 1.25 to 1.50 Meters Thick.................. 25

Table 5. Major Soils Identified in Louisiana that Developed in Pre-Peoria Loess Deposits Less Than 1.25 to 1.50 Meters Thick and Contain an Admixture of the Underlying Material Throughout..................... 26

Table 6. Comparative Differences Between Modern Soils Developed in Peoria and Pre-Peoria Loess in Louisiana and Having Similar Landscape and Internal Soil,Drainage Characteristics.............................. 27

Table 7. Particle Size Distribution in Memphis Soil and Underlying Paleosol on the Prairie Terrace in East Baton Rouge Parish, Louisiana........ 35

Table 8. Profile Distribution Trends of Phyllosilicates in the Clay-size Fraction of a Memphis Soil and Underlying Paleosol on the Prairie Terrace in East Baton Rouge Parish, Louisiana....................... 36

Table 9. Selected Chemical Characteristics of a Memphis Soil and Underlying Paleosol on the Prairie Terrace in East Baton Rouge Parish, Louisiana........................................................... 37

Table 10. Whole-soil Composition of Nine Elements and Ti/Zr Ratios in a Memphis Soil and Underlying Paleosol on the Prairie Terrace in East Baton Rouge p'arish. Louisiana........................................ 38

Table 11. Particle Size Distribution in an Olivier Soil and Underlying Paleosols on the Irene Terrace in East Baton Rouge Parish. Louisiana . ..... 0 ••••••••••••••••• e ••••••••• 0 8 • ~ • "" • 8 e e 0 III eo " " c c e c:I C :: 0 " = 0 ;) 45

Table 12. Profile Distribution Trends of Phyllosilicates in an Olivier Soil and Underlying Paleosols on the Irene Terrace in East Baton Rouge Parish, Louisianao .. ~ .... D •• It •••••••• II ",.0 •• 'I' o. 0 0 0"" G G I) 9 9 •••••••• " III e" 46

Table 13. Selected Chemical Characteristics of an Olivier Soil and Underlying Paleosols on the Irene Terrace in East Baton Rouge Parish, Louisiana ...... .• 0 •••••••• eo" 'II •• '0 G ...... 'II ••••••• 0 • 0 •••••••••• ~ 'I' ••• " I') • 47

Table 14. Whole-soil Composition of Nine Elements and Ti/Zr Ratio in an Olivier soil and underlying Paleosols on the Irene Terrace in East Baton Rouge Parish. Louisiana....................................... 48

v

Table 15. Particle-size Distribution in a Memphis Soil and Underlying Paleosol on the Prairie Terrace in Lafayette Parish. Louisiana •.... , .....•.. , 55

Table 16. Profile Distribution Trends of Phyllosilicates in the Clay-size Fraction of a Memphis Soil and Underlying Paleosol on the Pr&irie Terrace in Lafayette Parish, Louisiana.............................. 56

Table 17. Selected Chemical Characteristics of a Memphis Soil and Underlying Paleosol on the Prairie Terrace in Lafayette Parish, Louisiana...... 57

Table 18. Whole-soil Composition of Nine Elements and Ti/Zr Ratio in a Memphis Soil and Underlying Paleosol on the Prairie Terrace in Lafayette Parish, Louisianalll ........ o •••••••••••••••••••••••••••••• " ........ 00... 58

Table 19. Particle-size Distribution in a Baldwin Soil Unit Inclusion and Underlying Paleosols on the Holocene Mississippi River Alluvial Plain in Lafayette Parish, Louisiana................................ 64

Table 20. Profile Distribution Trends of Phyllosilicates in the Clay-size Fraction of a Baldwin Soil Unit Inclusion and Underlying Paleosols on the Holocene Mississippi RiVer Alluvial Plain in Lafayette Parish, Louisiana ... III ••••••••••••• lit •••• II' ••••••••••••••••• " ••••• 110 •• /I • 65

Table 21. Selected Chemical Characteristics of a Baldwin Soil Unit Inclusion and Underlying Paleosols on the Holocene Mississippi River Alluvial Plain in Lafayette Parish, Louisiana................................ 66

Table 22. Whole-soil Composition of Nine Elements in a Baldwin Soil Unit Inclusion and Underlying Paleosols on the Holocene Mississippi River Alluvial Plain in Lafayette Parish. Louisiana....................... 67

Table 23. Particle-size Distribution in a Duralde Soil and Underlying Paleosol on the Montgomery Terrace in Evangeline Parish, Louisiana........... 73

Table 24. Profile Distribution Trends of Phyllosilicates in a Duralde Soil and Underlying Paleosol on the Montgomery Terrace in Evangeline Parish, Louisiana.e ... " .................... e ••••••• "'e •••••••••••••••••••• 0 ••• 74

Table 25. Selected Chemical Characteristics of a Duralde Soil and Underlying Paleosol on the Montgomery Terrace in Evangeline Parish. Louisiana., 75

Table 26. While-Soil Composition of Nine Elements and Ti/Zr Ratio in a Duralde Soil and Underlying Paleosol on the Montgomery Terrace in Evangeline Parish, Louis iana. (I 0 •• III •• " & •• e eo. " ••• 0 .. It 110 ....... 0 It •• <ill •• II • III •• It 1'1 •• II Go • III • 76

Table 27. Particle-size Distribution in a Dexter Soil on the Macon Ridge in Franklin Parish, Louisiana .. It ••••••••••••• It •••••••••••••••••••• It •• ID. 86

Table 28. Profile Distribution Trends of Phyllosilicates in the Clay-size Fraction of a Dexter Soil on the Macon Ridge in Franklin Parish, Louisiana ..................... It •••••••• It ••••••••••••••••••• • It • • • • • • • 86

Table 29. Selected Chemical Characteristics of a Dexter Soil on the Macon Ridge in Franklin Parish. Louisiana .•...•••• 0 .. 0................... .87

VI

Table 30. Whole-soil Composition and Ti/Zr Ratio in a Dexter Soil on the Macon Ridge in Franklin Parish, Louisiana................................. 87

Table 31. Particle-size Distribution in a Memphis Soil and Underlying Paleosols on Sicily Island in Catahoula Parish, Louisiana........... 94

Table 32. Profile Distribution Trends of Phyllosilicates in the Clay-size Fraction ·of a Memphis Soil and Underlying Paleosols on Sicily Island in Catahoula Parish, Louisiana...................................... 95

Table 33. Selected Chemical Characteristics of a Memphis Soil and Underlying Paleosols on Sicily Island in Catahoula Parish, Louisiana........... 96

Table 34. Whole-soil Composition of Nine Elements and Ti/Zr Ration in a Memphis Soil and Underlying Paleosols on Sicily Island in Catahoula Parish, Louisiana................................................... 97

. -Table 35. Particle-size Distribution in a Memphis Soil and Underlying Paleosol

on the Macon Ridge in Franklin Parish, Louisiana •••••••••••••••••••• 103

Table 36. Profile Distribution Trends of Phyllosilicates in the Clay-size Fraction of a Memphis Soil and Underlying Paleosol on the Macon Ridge in Franklin Parish, Louisiana ••••••••••••••••••••••••••••••••• 104

Table 37. Selected Chemical Characteristics of a Memphis Soil and Underlying Paleosol on the Macon Ridge in Franklin Parish, Louisiana ••••••••••• 105

Table 38. Whole-soil Composition of Nine Elements and Ti/Zr Ration in a Memphis Soil and Underlying Paleosol on the Macon Ridge in Franklin Parish, Louisiana ...................................... 0" •••••• " • • • • 106

Table 39. Particle-size Distribution in a Memphis Soil and Underlying PaleosolS in Vicksburg, Mississippi................................. 114

Table 40. Profile Distribution Trends of Phyllosilicates in the Clay-size Fraction of a Memphis Soil and Underlying Paleosols in Vicksburg, Mississippi.... ... . . . . . . ... . . ... .. .. . . . .. .. . .. . .. . .. .. . . . . . . . . .. . . .. 116

Table 41. Selected Chemical Characteristics of a Memphis Soil and Underlying Paleosols in Vicksburg, Mississippi ••••••••••••••••••••••••••••••••• 117

Table 42. Whole-soil Composition of Nine Elements and Ti/Zr Ration in a Memphis Soil and Underlying Paleosols in Vicksburg. Mississippi ••••• 119

INTRODUCTION

There has not been a comprehensive regional study of the extensive loess deposits in the Southern Mississippi Valley. This field guide summarizes the results of investigations of the loesses in Louisiana and the Vicksburg, Mississippi area conducted by the authors and other workers. The included information and interpretations are based large1y on; characterization data from approximately 200 pedons of soils developed in loess in Louisiana; field-study transects (Figure 1) to determine the thickness, distribution and other characteristics of the loesses; data included in the field guide and similar data from selected sites on the transects and at other locations; and on information generated by other workers.

The field sites, supporting descriptions and analytical data have been selected to illustrate important features of the loesses and to show relationships among them. A number of key relationships with respect to the underlying units are also demonstrated at the various sites.

LOESS DEPOSITS IN LOUISIANA Historical Overview

The earliest known report of loess in Louisiana is Charles Lyell's (1847) description of loess bluffs facing the Mississippi River near Port Hudson in East Baton Rouge Parish. He believed these deposits had a fluvial origin and noted their similarity to loess of the Rhine Valley. Loess has since been reported in the state by a number of workers. Emerson (1918) described thickness and distribution of most of the loess deposits now recognized throughout Louisiana. He considered them to be aeolian in origin with the Mississippi River floodplain the major source. Russell (1944) attributed the. deposits to in situ formation through loessification. a specific weathering process in alluvium. Wascher and coworkers (1947) identified three superposed loesses in the Southern Mississippi Valley. They recognized calcareous and leached noncalcareous loess and identified both in Louisiana. Like Emerson (918), they considered the loess aeolian in origin from a Mississippi River floodplain source. Leighton and Willman (1950) showed loess covering Pre-Holocene surfaces near the Mississippi River floodplain in Louisiana. Daniels and Young (1968) described a loess deposit overlying the Prairie Terrace and on the west side of the Mississippi River floodplain in South Central Louisiana. They showed a continuous east to west thinning pattern for the loess. Spicer (1969) obtained data from two east-west transects in East and West Feliciana Parishes, Louisiana and showed a marked west to east thinning pattern. Touchet and Daniels (1970) described a post-Montgomery Pre-Prairie age loess in the area immediately west of the Mississippi River in Central Louisiana and showed a distinct east to west thinning pattern for the deposit. A Pre-Peoria loess was identified on the Bastrop Hills in Northeastern Louisiana in areas west of the Peoria loess mantle by Rehage (1980). He mapped the thickness and distribution of this loess and of the Peoria loess to the east on the Macon Ridge in Louisiana. Miller and coworkers (1982) prepared a loess thickness and distribution map for Louisiana based on a number of study transects. They identified one loess on the Prairie Terrace and two on older surfaces. Their map shows loess thickness decreasing in directions normal to the Mississippi River floodplain and suggests that the older loess is more extensive than the younger. The thickness and distribution of the two loesses identified in Louisiana (Miller,

1

2

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1982) are shown in Figures 1 and 2. Figure 3 shows the combined thickness and distribution of loesses in Louisiana. The recent Geologic Map of Louisiana (Snead and McCulloh, 1984) identifies areas having loess greater than one meter thick. These areas correspond approximately to the distribution of loess greater than one meter thick shown by Miller and coworkers (1982).

Lithology

A fresh. moist exposure of the unweathered loess r~veals a massive, coherent but friable yellowish brown (10YR 5/4) to light yellowish brown (10YR 6/4) calcareous silt. Secondary carbonate concretions and pulmonate gastropod shells are present in places. The unweathered loess is less than 10 percent clay «2 .0 micron). 85 to 95 percent silt (2-50 micron) and less than 10 percent sand (50-200 micron). The sand present is almost entirely very fine sand (50-100 micron). A distinctive distribution pattern of partjcles within the silt-size fraction (Figure 5) is characteristic of the loess (Lewis et a1., 1984).

Carbonate content of the loess. as CaC03

equivalent and exclusive of secondary concretions and calcareous fossils, is about 20 percent at most sites and ranges between approximately 15 and 30 percent. Both calcite and dolomite are present in relative amounts that are yet to be established in Louisiana. Snowden (1966) found dolomite more abundant than calcite in the unweathered loess at Vicksburg, Mississippi. Calcite is the indurating agent in the secondary concretions which expel very little, if any, of the surrounding matrix but concentrate certain elements such as Ba and S during formation (Qualls, 1984).

The noncarbonate clay-size fraction is almost entirely smectite (60-75 percent), micaceous minerals (20-25 percent) and kaolinite (10-20 percent) with trace amounts of vermiculite, chlorite, feldspars, and quartz. The silt and sand size fractions are comprised almost entirely of quartz (80-90+ percent). K-feldspars (5-10 percent) plagioclase feldspars (1-3 percent), mica (l-2 percent) and lesser amounts of amphiboles, epidote, pyroxenes, tourmaline, garnet. and zircon. Magnetite. ilmenite, rutile. goethite, and hematite may also be present (Snowden, 1966; Otvos, 1975; Miller, 1984 unpublished) •

Weathering, soil development. and mixing zones near loess-nonloess contacts can and do result in characteristics that differ appreciably from those of the unweathered loess.

Sec tions containing unweathered loess are restricted to parts of Sicily Island in Northeastern Louisiana. to that part of West Feliciana Parish lying north and west of St. Francisville and to isolated areas near the Mississippi River floodplain in South Central Louisiana. In these areas, the thickest loess deposits together with the steepest topography and consequent greater runoff and erosion have resulted in preservation of unweathered loess at depths of less than 2 meters in many upland areas.

Source and Distribution Patterns

The Mississippi River floodplain served as the source of the loess during periods of glaciation in the mid-continent area drained by the river and its

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tributary streams. Several lines of evidence support this conclusion. Loess deposits in Louisiana and Mississippi are restricted to preloess surfaces that form relatively narrow north-south bands on the east and west sides of the Mississippi River floodplain. Thickness of these deposits decrease at predictable rates as a function of distance normal to the floodplain (Wascher et al.. 1948; Spicer, 1969; Rehage. 1980; Miller et aI., 1982). A loess component cannot be identified on the more stable preloess surfaces in locations that can be predicted only in terms of distance from the floodplain. The suite of minerals identified in the unweathered loess is consistent with a Mississippi River sediment source during periods of active glaciation in areas drained by the river and that contain limestones and dolomites among the various rock types (Snowden, 1966; Otvos, 1975). There is a decrease in sand and an increase in clay-size particles in the loess as a function of distance from the floodplain. Within the silt-size fraction coarse silt decreases and fine silt increases with distance from the floodplain (Figure 5). Finally, thickness of the zone of pedogenic m1x1ng of loess with the underlying materials is inversely related to distance normal to the floodplain (Spicer, 1969; Rehage, 1980) reflecting relative rates of loess accumulation on pedogenically active landscapes.

In the North Louisiana area, maximum thickness of the Peoria loess is greatest on the east side of the Mississippi River floodplain with more than 12 meters accumulation at Vicksburg in Mississippi. This compares with 3 to 4 meters along the eastern edge of the Macon Ridge in Louisiana which lies across the floodplain west of Vicksburg. A reversal of this relationship southward is illustrated by comparing maximum thicknesses of 4 and 6+ meters, respectively. in the Baton Rouge area east of the floodplain and the Lafayette areas west of the floodplain in South Louisiana.

Thickness of the Pre-Peoria loess is greater on the west than on the east side of the floodplain in Louisiana and adjacent parts of Mississippi with the exception of the Sicily Island Hills in Louisiana. This exception is discussed in a section that follows. Maximum thickness on the west side of the floodplain increase southward from about 4 meters at the Arkansas-Louisiana state line to more than 9 meters at its southern limit. Observed IMximum thicknesses on the east side increase slightly southward from almost 4 meters in the Vicksburg, Mississippi area to about 5 meters at its southern limit. The described thickness relationships in both loesses may be due, at ] east in part. to increasing proximity of the Gulf of Mexico from north to south and the consequent influence of the Gulf on weather patterns, especially wind direction (Emerson, 1918). In view of the great width of the Mississippi River floodplain throughout Louisiana, it is also possible that potential sources of loess may have been considerably nearer the west than the east edge of the valley during deposition of both the Peoria and Pre-Peoria loesses.

The Peoria and Pre-Peoria loess deposits both appear anomalously thick on the Sicily Island Hills which lie near the southwestern edge of the Macon Ridge in northeastern Louisiana, For example, the Peoria loess deposits on the Macon Ridge thin from about 4 meters along the eastern edge to less than 2 meters near the hills then increase abruptly to 4 meters farther westward at the higher elevations on the hills. Two main factors are believed to cause the thicker deposits. First, the hills are a relatively small area (approximately 8 x 10 km) lying eastward of other upland areas having

7

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Particle Size (microns)

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Figure 5. Clay-free particle size distribution by Coulter, Counter technique. in the silt-size fraction from two soils developed~n Peori? loess in Louisiana.

comparable elevations. They are approximately 70 meters higher than surrounding areas on the Macon Ridge and Mississippi and Ouachita River floodplains. Their position is such that northerly. easterly or southerly winds could transport loess into the area from lower-lying potential sources. Second, changes in energies of winds from the lower potential source areas to the higher elevations may have contributed to the thicker deposits. Similar relationships between loess thicknesses and elevation have been observed in other loess mantled areas.

Geographic and Landscape Settings

The geographic and landscape distribution patterns of the loesses are a predictable consequence of their areas of deposition and subsequent erosion together with alluviation in the Mississippi River floodplain and along the Gulf Coast. Only the Peoria loess has been definitely identified on the Prairie Terrace and younger Pre"'Peoria surfaces . including the braided-stream Terrace comprising the Macon Ridge in northeastern Louisiana. Throughout its area of deposition on these surfaces erosion has been minimal and continuous loess deposits cover essentially the entire area. Post-loess alluvial deposits are absent and the loess deposits form the channel walls along most streams draining these areas. In places floodplain and/or gulf interfacing margins of the loess on the younger surfaces are buried by more recent alluvial deposits (Figure 3). Interrelated factors believed to have contributed to this 'alluvial drowning' include rising sea level at the end of the Pleistocene, landmass subsidence, and alluviation in the Mississippi River floodplain and along the Gulf Coast. Locally. one result of the 'alluvial drowning' is the presence. at the surface, of loess deposits occurring as outliers surrounded completely by more recent alluvium. Investigations show that these outliers represent areas with slightly higher elevations on a continuous loess mantled surface now partially covered by the more recent sediments.

The absence of the Prairie Terrace and younger surfaces at the time of deposition of the Pre-Peoria loess prevented their receiving these deposits (Figures 2, 3, 4). It is not known to what extent loess mantling the Pre-Prairie (Montgomery) Terrace extended southward before deposition of the coastwise component of the Prairie Terrace. Similarly. the eastward and/or westward extent of Pre-Peoria surfaces into areas now occupled by the Prairie Terrace and younger surfaces along the Mississippi River Valley is not known.

Comparison of the thickness and distribution patterns of the Peoria and Pre--Peoria loesses (Figure 2, 3 and 4) is sufficient to demonstrate that the Pre-Peoria is the more extensive of the two in the lower part of the Southern Mississippi Valley.

There is an apparant increase in the eastward and westward extent of both the Peoria and Pre-Peoria loess deposits near their southern limits of exposure at the surface. Possible explanations include wind directions, frequencies and energies and, possibly, more extensive loess source areas at the gulf coast-floodplain interface.

Land surfaces older than the Prairie Terrace could have received both Peoria and Pre-Peoria loess deposits. Surfaces older than the Intermediate Terraces of Snead and McCulloh (I 984) are generally the most dissected in

9

10

Louisiana. On these the landscape distribution patterns are somewhat analogous whether one or both loesses are present. Prairie age stream terraces are covered with Peoria loess --while most younger fluvial deposits la.ck a loess mantle. There is evidence that a loess covered Post-Prairie Terrace exists and received Peoria loess deposits (see Site 4). Pre-Prairie stream terraces and essentially the entire uplands are loess-covered in areas where the deposits are thickest. Traversing in the direction of thinning loess the underlying materials are first evident at the surface on the lower slope positions of the steepest landscapes. Continuing in this direction, the underlying materials are exposed at progressively higher slope positions and on less sloping landscapes. Only erosional remnants of loess may occupy the highest and/or most gently sloping landscape positions in loess covered areas most distant from the source.

Landscape distribution patterns on the Intermediate Terraces are quite analogous to those on the older surfaces. The effects of erosion in removing loess from these less dissected and more gently sloping surface are less pronounced and, of course, the age of stream terraces determines which, if either loess deposit is present on a particular terrace.

Basal Mixed Zones

Processes operative during and after loess deposition have resulted in a diffuse, gradational contact between the loess and the underlying unit. Thus, with increasing depth near the contact, the loess contains increasing quantities of an admixture incorporated from the underlying material. Useful criteria for identifying this mixed zone include color, structure, particle size distribution, element compositions, and kind and distribution of minerals in sand and/or silt and/or clay size fractions. Thickness of the mixed zone is inversely related to loess thickness (Figures 6, 7). The thinnest zones of mixing are thus beneath the thick loess deposits near the Mississippi River floodplain. The zones thickness increases with distance from the floodplain so that those deposits thinner than about 1.25 to 1.50 meters contain admixtures of the underlying material throughout.

The mixed zone is attributed to pedogenic processes, mostly bioturbation, active during and after loess deposition. The progressive thickening of the zones as the loess mantle becomes thinner reflects concomitant slow~r rates of deposition on a pedogenically active surface. The absence of distinct A and E horizons in soils buried by the loess can be attributed to their incorporation into the basal component of the loess.

Three general relationships are consistent with the presence of the mixed zone and continued thinning of the loess at depths of less than 1.25-1.50 meters; the apparant thickness of the mixed zone gradually decreases. the relative contribution of the underlying unit increases, and identification of the loess component is increasingly difficult.

The described basal mixed zone relationships have been demonstrated regardless of the nature of the unconsolidated underlying materials. The relationships are difficult to demonstrate in the field when another loess is the underlying unit but are readily apparant from mineralogical analyses (see data, Sites 2, 6 and 9).

500

450

400 U)

!....-

2 350 <l.l E ~ 300 c <l.l

u 250 c ........

U) 200 U)

<l.l

~ 150 u

.........

~ 100

50

0 0 5

U) U)

<l.l o -l

D (I)

X .. .-I

E c :=)

10 15 20 25

Distance in Kilometers

30

0) c ....... x ....... E·

4-o <l.l C o N

35

Figure 6, Thickness of loess and the zone of mixing in loess overlying sandy Coastal Plain deposits along an East-West transect in southeaStern Louisiana. (Source: data by Spicer (1968) and Miller (Unpublished data».

......

......

,,-... :::E u

'-'"

U) U)

UJ ::z: ~ u -JC I-

U) U)

L.U 0 -l

500., DISTANCE (KM)

400 ~ 0 19

300 1

200

100 I fJi I XED ZONE

5

MIXED ZONE DEPTH TO TOP THICKNESS OF MIXED ZONE

(CM) (CM)

22 378 79 0

BASE OF MIXED ZONE Y = 109.3 - 695.9 LOG (X + 10) R = 0.98

506.9

10 15 20 25 30 DISTANCE (KM)

FIGURE 7: LOESS THICKNESS AND THICKNESS OF ZONE OF MIXING ALONG AN EAST-WEST TRANSECT IN FRANKLIN PARISH~ LOUISIANA. (SOURCE: REHAGE~ 1980)

to-' N

Other Features

Leaching, weathering, pedogenic processes and other phenomona result in a number of features not already discussed but which warrant mention. Soils developed in the loess are discussed briefly in a separate section.

Depth of leaching

The depth of 'leaching of loess in the Southerri Mississippi Valley typically refers to thickness of the zone lacking free carbonates disseminated throughout the matrix. Wascher and coworkers (1947) reported that loess is leached free, of carbonates to a depth of 20 feet in the region. More thorough investigations have shown that depths of leaching are actually quite variable depending on such factors as age, thickness and setting of the loess among others. Depth of leaching of the Peoria loess ranges from less than 1 to more than 16 meters in Louisiana and adjacent parts of Mississippi. In areas of thick Peoria loess deposits on steeply sloping landscapes, runoff and erosion rates have been such that calcareous loess at depths of 1 meter or less is not uncommon. Areas east of the Mississippi River and near the floodplain from Vicksburg, Mississippi to St. Francisville, Louisiana typify this condition. In contrast, the Peoria loess is typically leached throughout on nearly level topography. This condition is typified by most Peoria loess deposits west of the Mississippi River in Louisiana as well as those on the Prairie Terrace east of the river. In these areas only small isolated places, mostly on steep escarpments, contain unleached loess at any depth.

The Pre-Peoria loess is leached throughout except on the Sicily Island Hills in northeastern Louisiana. The depths of leaching exceed 9 meters near its southern limits on the west side of the floodplain. On the Sicily Island Hills in Louisiana approximately 4 meters of leached Peoria loess overlies 1.5 meters of leached Pre-Peoria loess that is calcareous at greater dep,ths.

Color

Color of the soil developed in the loess or of the weathered loess beneath the solum are not reliable indicators of the age or nature of the materials. Differences in the weathering and pedogenic environments result in a wide range of colors in both the Peoria and Pre~Peoria loesses in Louisiana. The Peoria loess may range from predominante1y light gray or light brownish gray (10YR 6/1 to 6/2) in poorly drained areas to mostly brown (7~sYR 5/4) at the best drained locals. At most sites, the loess is mottled with varying proportions of gray to brown. Colors in the Pre-Peoria loess are similar except the best-drained sites may be predominantely red (2.5YR 4/6 to 5/6), especially in the upper part.

The basal transition zone beneath loess more than about 1.5 meters thick is generally characterized by one of two color relationships that is commonly associated with the nature of the underlying material. Where these underlying materials are more clayey than the loess the lowermost 1/4 to 3/ l1 meters of this transition zone is commonly grayer than the loess above. At sites ,,,here the underlying units are less clayey a comparable zone is generally darker (lower value and/or chroma) and may have redder hues when compared to the material above. Differences in moisture regimes in this zone associated with

13

14

differences in the nature of the underlying materials are thought to be the predominant factor responsible for these common color relationships.

Pedogenic Sands

Particle size distribution analyses of soils with restricted drainage may show unusually high sand contents in A. E. or' Bk horizons compared to the remainder of the material. Unaided eye through microscopic examination of these sands reveal secondary sand-size concretions of Fe and Mn or, in some soils, CaC0

3• Particle size analyses following appropriate

chemical breakdown of the concretions give results lacking anomalous sand contents.

Buried Soils

The loesses in Louisiana are underlain by readily recognizable buried soils almost everywhere. Morphology together with physical, chemical, and mineralogical data indicate that Paleo Ultisols, Alfisols, Inceptisols, Entisols or Vertisols may occur depending on the age of the buried surface and other soil determining characteristics of the Paleo environment. It is evident from the discussion of the basal mixed zone that beyond some point in the thinning loess two distinct units (loess over buried soil) separated by the mixed zone can no longer be distinguished. In such areas, the loess contains an admixture of the underlying material throughout. Here it is recognized as a silty mantle that forms a continuum with the mixed zone beneath the thicker loess deposits nearer the source. Even in most of these areas mid- to lower B horizons of buried soils can be identified beneath the more silty mixed zone.

Loess overlying stratified material having minimal or no soil development has been recognized in two general areas in Louisiana. One such area is near the southernmost limits of the exposed Peoria loess on the east' side of the Mississippi River floodplain. Another is in the area on the west side of the river corresponding to the loess covered terrace paralleling the floodplain and at a lower elevation and eastward of the Prairie Terrace in southwestern Louisiana. In both areas, the underlying materials are predominately clayey deposits of undetermined thickness.

Stratigraphy

Selected 14C and Thermoluminescence dates relating to loess stratigraphy in the lower Mississippi Valley are included in Table 1. The author's interpretations of major relationships among loesses identified at Vicksburg. Mississippi, on the Sicily Island Hills in Louisiana, Evangeline Parish in West Central Louisiana. the Irene and Prairie Terraces in Louisiana, and on Crowley's Ridge in Arkansas are summarized in Figure 8. Other major stratigraphic relationships in Louisiana are illustrated at Sites 1 through 9.

The first major stratigraphic study of loess in the lower Mississippi Valley was done by Wascher, Humbert, and Cady (1948). They recognized three loesses in the region and correlated the youngest with the Peoria loess of the upper Mississippi Valley. The intermediate unit was correlated with the 'Late Sangamon Loess' of the Illinois River Valley. The oldest was not correlated and was identified as the 'Third loess'.

15

TABLE 1

SIGNIFICANT 14C AND THERMOLUMINESCENCE OATES RELATING TO THE LOESS STRATIGRAPHY IN THE LOWER MISSISSIPPI VALLEY

--- -----------. -.------------------ ----Locat ion La b No. Date Mat. Significance Source

Vicksburg, Ms. 9,000 to loessl TL dates for Peor i a Johnson et a I .• 1984 21,000 soi I loess.

Vicks bu rg , Ms. 75,000 to soi II TL dates for Pre- Johnson et a 1. , 198/j 95,000 loess Peor i a loess of

Mi 11 er et a 1. , 1982.

Vicksburg, Ms. 120,000 to soi 11 TL diltes for Loveland Johnson et a 1. , 198/j 135,000 loess (7) of Miller ·et

a 1., 1982.

Vicksburg, Ms. OX-185 17,850 +380 she 11 Li es above possible SnOl·,den and Priddy, Jules Soi 1. 1968

Vicksburg, Ms. OX-1811 19,200 ::.420 shell Li es below possible Snowden and Priddy, Jules Soi 1. 1968

Vi cksburrj, Ms. 1-1681 22,600 ::.800 she 11 Lies below weak Snowden and Priddy, paleosol but near 1968 top of Farmdale Loess.

Vicksburg, Ms. 1-1386 25,300 ::'1,000 shell Li es near base of Snowden and Priddy, Farmdale Loess. 1968

Vicksburg, Ms. .0X-I72 25,600 ::,1,000 wood From paleosol beneath Snowden and Priddy, Farmdale Loess. 1968

Sic i 1 y Island GX-6483 27.500 ::,1 ,200 shell From base of Farmdale Miller, 1982 Hill s, La. Loess.

Tunica, La. UGa-836 20,690 ::,250 she II Oates upper loess in Otvos, 1975 S. E. Louisiana.

Tunica, La. UGa-8/1 21,570 ::.310 she II Oates upper loess in Otvos, 1975 S.E. Louisiana.

CIl H 'Q) -I-l Q)

S I=l

'M ,..c:: -I-l 0. Q) '0

Q) -I-l

~ 'M ~ a H 0.

~

0_

5 -

10_

15_

Crowley's Ridge in Ark.

~~~1!-!C!!:!! ennu Ina Lorlns IoU (YGat flit Gil •• 19110).

DI .. a"na lotp". c~;i:iiinl'b;rl.d 'IOU III •• , ot 01., 1'101.

I:!tv.I~n4..1'\'jI! CnnlAlnl .... 104 •• n Illeu 01 d., 1"01.

4th In ••• Au-t i;~r;'lnt ell'pro tilt hnD bam." on (teld ob •• tvo-e artn lit .t tel d.ou pre.,.,"d by II .. , lUlU ••• ond rlold ond Iobou •• .,. dAU C'~.,ftrhnn1ll with L .... I mn~ III .r IIUh. et &1 ••• ,.an

Contalne ~uri.& sail.

5th Jo ••• Aut.i~nr; inti?rrretsthtill b:1sed C'tll dau by Weu (1978) ond •• tchg .n CrlNh,', lUd.e, a mlB'lIIVf l-t r and land,. II'rePltlatot'"n. drpoeU. t~nnf"ln/lill hllrhd IIUU.

\ \

Vicksburg area, Ms.

PecIC," IOf!J! (Jo!ilnaoill $t mI., UI!I4a 111110. c~ al., 1911, BilOW •• , le"l R_ •• ond fl.OIdy, nUl n ... lalot ... • "d 11111 .... , 1"01 W ••• loe. ot d .. 1948).

V! C'aJlbUI'lL1!!!nll 1ifii.ltii~y ond-YvL"obuU. 1961).

Conulndl H.arhi. SoU (IIUh. U d., IU2).

.. .. ~

~ .. • ~

11 Uno ion to !ar.!." !.ns.man Joe •• (Jollllilon at er::-miJ. . . ~!!!!.d_lJUa..!.~ (Hillor ot 01 .. 19821. POIIRlhl. PrlP-r"uria Uo.u. 1WiiitOR'and iii1 i;''''-1950). !2!!!I>lio 4th 100010 U"",,d •• , 11166). Centa1'lIi ~.t.ld lll'u, _. BaDlI1 )ilmed 1.one "iiim~7iml.

!iJJ~I/III_~ppp .. ___ d/8I

__ ==-====-~=-Qm~SB .. amDmeE __ ... qmummEURE~.~~UU"ES .. uaam .. -,

Montgomery Sicily Island Irene Terrace Prairie Terrace Terrace Hills in La. Irene, La. Baton Rouge, La. Turkey Creek

I • iii ---l!!r!U!'!!!! Conteins Mlaaphi. Soil IIIUI ... t d., I'UI.

... 01 Khud Zona (Ktllor

.t al •• 1982).

',.-'.orl.o 10 ••• C;;t;fnii-buri.ci -.011 (lilUo. 0& 01., 1982).

.'t~! I J1l ~!4 l!1!I. iiiu In at .J., nU).

Cltronoll!..!!1 'OrNtion ContOln. bll.I.T80i j_. 1111110. at 111.. 19821.

hrl~ aUdio 1I10.n .. oln lii.i. (Johnooii"ct'.i.,-· iii4}. Pre-roorl. 100,. OUII •• OTii:·, -nm~' .. Loveland 10 .... (Snovdpn ;;iidTriddy .-i968: Snovd.n 19661 Lel,bloft and WIll .... 1950) • .~!!:!! !~!!!!!.r ___ ~~~ (IlrinUaeky 12M Turnbull. nUl.

PMr" 1o ••• Ci..i.I ... · oil.,o. Doli IIIUlu ot al.. ltl2).

.... t MI •• d Zone iiiiil •• 01 01., 19GZ).

".-'l'Orl1 10.'. C;;;;iiiini burl.d 11011. IKUlo. ot 01 .. 1912)

1In •• 1 Hl ... d Zona litiii •• ot 81 .. 1982) •

Ir .... Terrace CtmrfttLnB bur ••• loll. '"1110' oC al., 1982) •

ronrlft IDr ... Cnni.i~ MOat-ble RuU. IIIU1 •• oc al., nUl.

.;;.THi.;'d i;M- -'jiiiiiOr"OiGr::-19U1 •

Prairte ronaatlon Containe b"r1e4 .nU •• IKU1 •• ot al., 1'82.

I

tr~:r~lI.!.J"'·~ CIonl."" __ .. 11011 IPIllln, ItOi ........ U.' dna).

~r!-:l!~I!!l!. ~~!.t: ~n!a"",u, n .... o .. I To""Ito' ...... DII .. t"I., IU701 •

.... IIUmo4 ZliuUo., nil, __ U._ .... ul.

!!!!!tu-·!'L!!>!!!!l!~!! Contat •• \lurlM 1M" IPIUlev, UBI, __ 11'- .... t.).

Figure 8. Relationships among loesses identified and correilated at six locations in the Lower Mississippi Valley (compiled, 1984, by B. J. Miller from sources referenced).

La.

I-' ()\

In a subsequent study, Leighton and Willman (1950) recognized the three loesses identified by Wascher and coworkers and renamed the two lowermost units. They correlated the intermediate unit as Farmdale and the lower unit as the Loveland of the Illinoian glacial. They also tentatively identified remnants of a Pre-Loveland loess.

Krinitzsky and Turnbull (1967) studied loess deposits in Mississippi and agreed that there is more than one loess in the lower valley. They considered it premature to try to precisely correlate these units with loesses of the upper valley. They named the uppermost loess 'Vicksburg' and identified the intermediate loess of earlier workers as an 'Intermediate transition zone'. The lower loess was identified as the 'Pre-Vicksburg'. They tentatively correlated the well developed Paleosol in the Pre-Vicksburg unit as a Sangamon Soil.

Work in the Vicksburg, Mississippi area by Snowden (1966) and Snowden and Priddy (1968) established that the upper loess is a correlat~ve of the Peoria loess of the upper Mississippi Valley. They obtained C dates clearly showing tr~t the bulk of it was deposited during Woodfordian time. They also obtained C dates of 22,600 BP and 25,300 BP, respectively. on the upper and basal components of the middle (Farmdale, Basal Transition Zone) loess. They identified a Farmdale· soil in this component. They studied the dark bands ('bedding layers') evident in many fresh Peoria loess exposures and considered them to be we1\ Paleosols. One such band in the Peoria loess at Vicksburg was bracketed by C dates of 17.BOO ± BOO BP and 19.200 ± 420 BP These workers also identified the well developed Paleosol in the Third (Sangamon, Pre-Vicksburg) loess which they identified as Pre-Farmdale. They identified yet another Paleosol beneath the one in the Pre-Farmdale loess and tentatively considered it to have developed in loess.

In southwestern Louisiana Daniels and Young (1968) showed that a single loess deposit overlies the Prairie Terrace west of the Mississ:1.ppi River. They did not attempt to correlate the deposit with other loesses and assigned it a Post~Prairie Pre-late Holocene age.

Touchet and Daniels (1970) identified a Pre-Prairie Post-Montgomery loess on the Montgomery Terrace north of the area on the Prairie Terrace studied by Young and Daniels (1968). Superposed loesses were not identified because the depositional pattern of the Post-Prairie loess is such that only a very thin component would be expected locally on the Montgomery Terrace.

Otvos (1975) has used 14C dating to establish that southeastern Louisiana is analogous to the Peoria Mississippi.

the uppermost loess in loess at Vicksburg,

Rehage (19BO). working in northeastern Louisiana identified and mapped a Pre-Peoria loess westward of the Peoria loess band which he also mapped. He identified multiple source areas for the Pre-Peoria loess which was tentatively assigned to the Farmdalian substage. The Peoria loess was considered to have a Mississippi River floodplain source.

Miller et a1. (1982) identified three distinct loesses at Vicksburg, Mississippi and identified the uppermost as Peoria and correlative with the youngest loess in Louisiana. They identified the intermediate loess

17

18

(Farmdale, Basal Transition Zone, Pre-Vicksburg, etc. of earlier workers) as a zone of pedogenic mixing of Peoria loess with the underlying buried soil. The second loess (Sangamon, Loveland, Pre-Farmdale of earlier workers) was identified only as Pre-Peoria. They considered this loess corr1~ative \-lith the Pre-Peoria loess they mapped in Louisiana and obtained a C date of 27,500 ± 1,200 years B. P. from gastropod shells near its base on the Sicily Island Hills in Louisiana. The third loess identified at Vicksburg was tentatively identified as Loveland (?) and contained a well-developed Paleosol. This third loess was not definitely identified in Louisiana.

West (1978) and West, Rutledge and Barber (1980) studied loesses on Crowley's Ridge in Arkansas. They identified three superposed loesses and correlated, them top to bottom, as Peoria, Roxana, and Loveland. The senior authors visits (1984) to sites studied by West, Rutledge and Barber (1980) result in the observations that follow. Their Peoria loess is considered correlative with the Peoria loess of Miller, et al. (1982) at Vicksburg, Mississippi and in Louisiana. Their Roxana .1oess is either absent at Vicksburg and in Louisiana or is present in amounts too small to exceed the thickness of the relatively thin Pedogenically mixed basal transition zones. Their Loveland loess is correlative with the Pre-Peoria loess identified at Vicksburg and in Louisiana by Miller et al. (1982). Observations at their field sites, study of data by West (1978) and comparison with data on the Loveland (?) of Miller et al. (1982), and consideration of the setting atop Crowley's Ridge (a gravelly to sandy Pre-Pleistocene formation), led to the conclusion that a fourth loess is present which is correlative with the L0\1e1and (?) loess (Miller et al., 1982) identified at Vicksburg. Data published by West (1978) not only supports this conclusion but suggests the possibility of yet another deeper (fifth?) loess not actually observed during the field study.

Johnson and coworkers (1984) collected samples for thermo1uminesence dating from near the Mississippi Standard loess section at Vicksburg. They reported an upper Peoria loess sequence. witl1 dates ral1gillg from 9,000 to 21,000 BP. Their second loess (the Pre-Peoria of Miller et a1 •• (1982)) yield Early to Middle Wisconsin dates of 75,000 to 95,000 years BP. Their third loess (the Loveland (?) of Miller et aL (1982)) was considered Late Illinoian or Early Sangamon with dates of 120,000 to 135,000 BP.

I

I·

Twenty Questions

1. In regard to the High, Intermediate, Prairie, and Deweyville Terraces of Snead and McCulloh (1984) in Louisiana, how many are present and what are their ages; can at least remnants of the Roxana Loess of West, Rutledge and Barber (1980), the Loveland (?) loess of Miller et al. (1982) and the lowermost (5th) loess tentatively identified (Miller, 1984) on Crowley's Ridge in Arkansas be identified in Louisiana and provide some of the answers to these questions?

2. Is the Montgomery Terrace (an Intermediate Terrace of Snead and McCulloh, 1984) Sangamon. Yarmouth, or older; does the presence of buried soils in its surface and the presence only of the Pre-Prairie and/or younger loess (Miller et al.. 1982) provide part of the answer?

3. Is the Prairie Terrace in Louisiana Sangamon in age, or is it younger; does the identification on its surface of only the Peoria loess above buried soils having moderate development give any indication; is there a component of the Roxana in the basal mixed zone beneath the Peoria loess; does the minimal dissection of its surface and the presence of high base status soils (some of which contain secondary CaC0

3) argue for a younger

than Sangamon age or merely reflect the clayey nature of the deposits together with high water tables and low elevations?

4. Is the Terrace comprising the Bastrop Hills in northeastern Louisiana Prairie as mapped (Snead and McCulloh, 1984); if so what is the explanation for the presence on its surface of the Pre-Peoria loess (Miller et al.. 1982) and the absence of this loess from all other Priarie Terraces shown in Louisiana by Snead and McCulloh (1980).

5. Is there a fluvial. and possibly coastwise terrace in Louisiana in which late periods of deposition immediately preceeded or were contemperaneous with early Peoria loess deposition as suggested by field evidence; if so. is this the Deweyville Terrace, an Unnamed Farmdale Terrace. other?

6. Is the Loveland(?) loess of Miller et al. (1984) at Vicksburg present as thin (mixed zone) remnants on the High Terraces of Snead and McCulloh (1984) in Loulsiana as suggested by field observations at selected sites?

7. Which, if either, of the older loesses at Vicksburg (Pre-Prairie and Loveland(?) of Miller et al. 1982) is correlative with the Loveland of Iowa. Nebraska. Kansas, Missouri. etc. in the Midwest?

8. Whatever its midwest correlative, if any, what is the reason(s) for the extensive distribution of the Pre~Peoria (Miller et al., 1982) loess in the Southern Mississippi Valley compared to the Midwest?

9. Does solum development in the buried soil contained in Pre-Peoria (Miller et al., 1982) loess that is comparable to development of modern soils in Peoria loess argue for a younger than Sangamon age for the Pre-Peoria loess?

19

20

10. What is the southernmost extent in the Lower Mississippi Valley of the Roxana loess on Crowley's Ridge in Arkansas (West, Rutledge and Barber. 1980)?

11. Is there a component of the Roxana loess identified on Crowley's Ridge in Arkansas (West, Rutledge and Barber, 1980) present at Vicksburg, Mississippi but in amounts too small to exceed the thickness of the basal mixed zone between the Peoria and Pre-Peoria loesses of Miller et al., 1982?

12. What is the explanation for the minimal development of buried soils within the Roxana loess throughout its distribution area: is it everywhere truncated; is it a 'cumulative' soil (or a Welded soil of Ruhe and Olson, 1980) that developed throughout the Roxana formation contemporaneous with very slow deposition rates during most of Altonian time and, if so, why is it not more developed in the lower Mississippi Valley (Le. Crowley's Ridge in Arkansas); do characteristics of this soil possibly indicate much cooler and drier paleoclimates during both the Altonian and Farmdalian substages throughout the Mississippi Valley when compared to the present; other?

13. Is Miller's interpretation that on Crowley's Ridge in Arkansas there are two loesses beneath the Loveland of West, Rutledge and Barber (1980) correct?

14. If there is(are) loess(es) on Crowley's Ridge in Arkansas older than the Loveland of West, Rutledge and Barber (1980) what is its (their) age and midwest correlative(s), if any?

15. In view of regional differences in climate, weathering, pedogenic processes, etc., how does thickness and other characteristics of the basal mixed zone in loess differ among regions?

16. Has the basal mixed zone between loess and the underlying unit possibly been interpreted as a separate formation less than about 1.5 meters thick by some workers?

17. If the thermoluminescence dates (Johnson et al., 1984) place the loesses at Vicksburg in the correct time frame (Peoria loess at 9,000 to 21,000 years BP, an Early to Middle Wisconsin loess at 75,000 to 95,000 years BP, and a Late-Illinoian to Early Sangamon loess at 120,000 to 135,000 years BP), is their Early to Middle Wisconsin loess (Pre-Peoria loess of Miller et al. 1982) a Late Sangamon loess and, if so, does it have a correlative loess in the midwest; is their Late-Illinoian to Early Sangamon loess (Loveland(?) of Miller et al. 1982) interglacial or is it indeed Loveland as suggested by Miller et al. (1982)?

18. What is the time zero control for thermoluminesence dates of unweathered loess; time of transport andlor deposition only; some 'average I date of the various components from various sources that comprise the loess; a combination of the two; other?

19. What do thermoluminesence dates of buried soils and weathered loesses reveal: time of transport and deposition of the parent material; time of burial of the soil; time of soil development and formation of secondary minerals; some combination of these; other?

20. What is the effect on thermoluminescence dates of b lending varying proportions of similar materials that give appreciably different dates; with proper proportions can a series of dates intermediate between the two be obtained?

21

22

. . . . MODERN SOILS DEVELOPED IN THE LOESSES

Nearly one-third of the land surface in Louisiana is comprised of soils developed in thick loess deposits (>1.25 to l.50· meters) or in thinner deposits containing an admixture of the underlying material throughout. The more than 50 soil series represented are approximately equally divided between those developed in Peoria and those in the Pre-Peoria loesses. Soils that classify in the Alfisol, Inceptisol. MolHsol, . and Ultisol orders in Soil Taxonomy (Soil Survey Staff, 1975) have developed in the loesses. Differences in age of the materials and thickness of the deposits are the basis for the four major groupings of soils in Tables 2, 3, 4 and 5.

Soils developed in the loesses have surface '(A) horizons with silt loam, or in places, silt textures. All but the Natchez soil have easily identified eluvial (E) horizons with textures comparable to the overlying A. The Natchez soil (Typic Eutrochrept) lacks. an eluvial horizon and the horizon of secondary accumulation of clay, argillic horizon, common to all the other soils. The Natchez soil has developed in thick loess deposits on steeply sloping areas where unweathered calcareous loess is present at shallow depths. Depth to the top of the argillic horizon in the remaining soils is typically less than 0.5 meters. Textures in the argillic horizons are silty clay loam or silt loam.

. . ." . Among the various soils, there is a wide range in color, organic matter

content, soil pH, structure, solum thickness and the kind and thickness of subsurface horizons. Secondary accumulations of either CaC0

3 or high levels

of exchangeable Na, or both, may be present in some argillic norizons whereas, others may contain fragipans and still others have add argillic horizons lacking these features.

Comparisons of the soils developed in Peoria loess and their classification (Tables 2 and 3) with those developed in the Pre-Peoria loess (Tables 4 and 5) suggest important similarities and differences between the two groups. Inceptisols, Alfisols and Ho1lisols have developed in the Peoria whereas only Alfisols and Ultisols are identified in the Pre-Peoria loess. The more weathered nature of soils developed in the Pre-Peoria loess is likewise demonstrated by the predominance of . siliceous mineralogy classes in contrast to the mixed mineralogy class of all soils in the Peoria loess. .

Field and laboratory· studies consistently· demonstrate a large number of significant differences 'bet~yeeri individual soils developed in the two loesses and having analogous landscape positions and internal soil drainage characteristics. Differences in time may be the major variable in pedogenesis of such soils, although constancy with respect to climatic and biotic factors during their formation has not been established •. Major differences between such soils are summarized in Table 6 • Soil Survey reports (not included in reference citations) that illustrate many of these differences include those now published or in preparation for Acadia, Allen, Ascension, Avoyelles, Catahoula, East Baton Rouge. Evangeline, Franklin, Iberia, Lafayette, LaSalle, Morehouse, Ouachita; Rapides, St. Landry, St. Martin. St. Mary, qt. Tammany, Tangipahoa, and West Carroll Parishes. Other works that illustrate these differences include Landry et a1.. 1976; Fleming, 1984; Goh, 1984; Qualls, 1984; Rehage, 1980; Soil Survey Staff, 1979; Bartelli, 1973; Touchet and Daniels, 1970; Spicer, 1969; Daniels and Young, 1968.

TABLE :2. MAJOR SOILS IDENTIFIED IN LOUISIANA THAT OEVELOPED IN PEORIA LOESS DEPOSITS THICKER THAN 1.25 TO 1.50 METERS

ORDER SUBORDER GREAT GROUP SUB GROUP FAMILY CLASSIFICATiON

TEXTURE MINERALOGY

InceptisoJ Ochrept Eutrochrept Typic coarse-s i I ty mixed

Alfi sol Udalf Hapludalf Typic fine-silty mixed

Aquic fine-silty mixed

Glossaqulc fine-silty mixed

Fragiudalf Typic fine-silty mixed fine-silty mixed ·f i ne-s i I ty mixed

Aquic fine-silty mixed

Glossaquic fine-silty mixed

Glossudalf Aquic fine-silty mixed

Aqualf Ochraqualf Aerie fine-silty mixed fine-si Ity mixed fine-s i lty .mixed

Glossaqualf Typic fine-s i Ity mixed fine-silty mixed fine-silty mixed fine-silty mixed

Albaqualf A'er ic fine-silty mixed

Natraqualf Glossic fine-silty mixed fine-silty mixed fine-silty mixed

Albic Glossic fine-silty mixed fine-sIlty mixed

Moll isol Aquoll Arg i ilqu,O 11 Typic fine-silty mixed

TEMPERATURE

thermic

thermic

thermic

thermic

thermi c thermic thermic

thermic

thermic

thermic

thermic thermic thermic

thermic thermic thermic thermic

thermic


thermic thermic

thermic

SOIL SERIES

Natchez

Memphis

Fred

Coteau

Gjgger Grenada loring

01 ivier

Calloway

Egypt

Acy Essen PatoutviHe

Calhoun Fountain Frost Gilbert

Springfield

Bonn lafe Verdun

Deerfcxl Foley

./eanerette

N W

TABLE 3. MAJCR SOILS IDENTIFIED iii LCUISIANA THAT DEVELCPED IN PEORIA LOESS DEPOSITS LESS THAN 1.25 TO 1.501 METERS THICK AND CONTAIN AN ADMIXTURE OF THE UNDERLYING MATERIAL THROUGHOUT.

ORDER SUBCRDER GREAT GOuR.,. SUB ~:ROOP FAMILY CLASSIFICATICN

TEXTURE MINERALOGY TEMPERATURE

Alfisol Udalf PaleudaU Tllpic; fine-silty mixed thermic:

Hapludalif Ultic; fi ne-s it ty mixed thermic

F rag ii ud.;11 f T1IPic; fine-s 11 ty mixed thermic

G 1 oss.aqu i c: fine-silty mixed thermic

lSoil5 at most sites developed in ,!,reo-Peeda rather than F'eoria loess mixed zones and have siliceous mineralogy. Soils are Ultisols at many_sites.

SCIL SERIES

Lexington 1

Dexter

providence

Necessity

1

N .J::--

TABLE 4. MA,IOR SOILS IDENTIFIED IN LOUISIANA THAT DEVELOPED IN PRE-PEORIA LOESS DEPOSITS MORE THAN 1.25 TO 1.50 METERS THICK.

ORDER SUBORDER GREAT GROUP SUB GROUP FAMilY CLASSIFICATION

TEXTURE MINERALOGY

jld f.isol Udalf Pa 1,~uda 1 f lIypic fine-sitty siliceous

G)os:saquic fine-silty s i1 i ceous

Hapludalf Ultic fi~ilty mixed

Fragiudalf Typic fi ne-5 i 1 ty siliceous

Glo5sudalf HapTic fine-s i1 ty mixed

Fragl i c fine-silty mixed

J\quic fine-silt:y sil i ceous

Aqualf Albaqualf Aeric. fine-silty mixed

Glossaqualf lrypi c fine-silty s i1 i ceous fine-silty mixed fine-silty mixed

Ultisol Udult Pah!udult lrypic fine-s ilt:y 5i liceous

1Not all soils that classify in this :series contain a component of loess.

2Mos t pedons have si I iceous rather than mixed ~ineralogy.

TEMPERATURE

thermic

thermic

thermic

thermic

thermic

thermic

thermic

thermic


thermic

SOil SERIES

Unnamed

Abita

Oossman2

Bussy

Evangel ineZ

Duralde2

Ti llou

Tenot2

Caddo Z Calhoun 1 2 .... rightsville '

Unnamed

N V1

TABLE 5. MAJOR SOILS IDENTIFIED '" !LOUISIANA THAT DEVELOPED IN PRE-PEORIA LOESS DEPOSITS LESS THAN 1.25 TO 1.50 METERS THICK AND CDNTAIN AN ADMIXTURE OF THE UNDERLYING MATERIAL THROUGHOUT.

ORDER, SUBORDER GREAT GROUP SUIB GROUP

Alfl so I Udalf Fragiudalf Typic

Glc)ssaquic

GJossudalf Aquic

Aqualf Albaqualf Aerlc

G 1 ossaqua If Typic

Ultisol Udult Paleudult Typic

Pllntllic

PI iinthaquic

FragllJduH Typic

l Not 311 soi Is that classify in this seJries contain a component of loess.

ZMost pedons have siliceous rather than m'ixed mineralo9Y'

FAMILY CLASSIFICATION

TEXTURE MINERALOGY TEMPERATURE

fine-silty mixed thermic fine-silty si I iceous thermic fine-silty mixed thermic

fine,.silty siliceous thermic

. fi ne-s i I ty s i li ceous thermic

fine-si-lty s i 1 iceous thermic

f i ne-s i I ty mixed thermic

fine-silty mixed thermic

fine-loamy si I iceous thermic fine-loamy siliceous thermic

fi ne-s i1 ty siliceous thermic

fine-s i I ty siliceous thermic fine-silty siliceous thermic fine-silty siliceous thermi c fine-silty si I iceous thermic

SOIL SERIES

Bude2

Libuse ProvidenceZ

Fluker

Frizzel

Mamou 1

Waller Z

UnnamedZ

Bowie' Malbis'

Beauregard 1

Debute 1 Savannah Tangi Toula

N

""

Table 6. Comparative differences between modern soils developed in Peoria and Pre-Peoria loess in Louisiana and having similar landscape and internal soil drainage characteristics.

Soil Characteristic

Solum thickness Thickness of A + E horizons Color (Hue) Maximum clay content in argillic Total clay content in solum Weatherable minerals in nonclay fraction Amount of smectite clay Amount of micaceous clay Amount of kaolinite clay Interlayering/interstratification of clay Fe-oxide content . CEC per unit of clay Soil pH pH-dependent CEC and acidity Extractable acidity (BaCl -TEA) Percent Al saturation (efrective CEC basis) Percent base saturation (effective, NH

40Ac

at pH 7.0, summation of cations) Exchangeable Ca/Mg ratio Total and extractable P

Soil Parent Material Peoria loess Pre-Peoria loess

least greatest least greatest least red reddest least greatest least greatest greatest least greatest least greatest least least greatest l.east greatest least greatest greatest least highest lowest least greatest least greatest least greatest greatest least

greatest least greatest least

27

28

MATERIALS AND HETHODS

Study Transects and Loess Thickness and Distribution Map

Study transects to determine the thickness and distribution of loess were completed in the approximate locations shown in figure 1. Each transect was initiated in the thickest loess deposits and progressed, in the direction of thinning, to a point where a loess increment could not be identified. Cores, approximately 5 cm in diameter, were collected at frequent (1/8 to 2~ mile) nonregular intervals in the most stable landscape positions along each transect to the shallower of the base of the loess or 9 meters using the Giddings hydraulic soil sampling unit. Data from these transects, together with supplemental obsprvations in road cuts, mine excuvations, etc., are the basis for the maps (Figures 2, 3 and 4) showing the approximate distribution and maximum thickness ranges of loess in Louisiana.

Site Descriptions and Sample Collection

Site 9 was sampled and described to a depth of 12.95 meters from a road cut under construction at the time. The material below 12.95 meters was sampled and described from'three cores, approximately Scm in diameter, taken with a Giddings hydraulic soil sampling unit. Site 6 was sampled and described from the face of an abandoned gravel pit. The remaining sites (1, 2, 3, 4, 5, 7 and 8) were sampled and described from multiple cores, approximately 5 cm in diameter, taken with a Giddings, hydraulic soil sampling unit.

Particle Size Analyses

Particle size analyses of the less than 2,000 micron fraction were done by pipet and sieve (Day, 1965). The determinations were carried out under controlled temperature conditions (72F ± 1.5). Organic matter and free carbonates were not removed for the analyses.

Particle size analyses of the 2.0 to 50 micron fraction were also done by Coulter Counter using the method described by Pennington and Lewis (1979). The Coulter Counter TA II Automated Analyser was used for the analyses. Fifteen particle size subdivisions were made over the 2.0 to 50 micron range for each sample.

Clay Mineralogy

The profile distribution trends of Phyllosilicate minerals at each site were determined from X-ray diffractograms of K and Mg-saturated clays. Although profile' distribution trends of a given mineral are readily appaxent from diffractograms, the relative quantities of each mineral in a given horizon can be estimated with limited accuracy. This is especially true in those soil horizons containing an appreciable component of interstratified and/or interlayered Phyllosilicates. Additional analyses, now in progress, are designed to further facilitate quantitative estimation of amounts of the various minerals' identified. Thus, the relative amounts indicated in the tables represent preliminary and tentative estimates that may be modified as additional data is generated.

The entire clay-size fraction was separated by siphon, after required sedimentation time, from whole soil samples dispersed by treating with 0.125% Na-hexametaphosphate solution followed by shaking overnight in a reciprocating shaker. The separated clays were combined, then divided into two equal subsamples. One sUbsample was flocculated with KCl solution, the other with MgC1 2 solution. The flocculated clays were washed free of salts by repeated centrifugation and decantation. A mount of both the concentrated K- and Mgsaturated clays was prepared and allowed to dry at laboratory conditions.

Diffractograms were made of the air dry Mg and K-saturated clays. The Mg-saturated clays were then placed in ethylene glycol vapors at 800 C overnight to provide for lattice expansion of any smectites present and a second diffractogram made. The K-saturated air-dry clays were subsequently heated to 3000 C and 5500 C for a minimum of four hours and diffractograms made after ':!(lch treatment. All diffractograms were made using Cu Koo radiation and a Philips-Norelco vertical goniometer.

Elemental Composition

The content of 26 elements in the less ,than 2,000 micron fraction was determined by Dr. S. E. Feagley, Agronomy Department, Louisiana State University. A method outlined by Bernas (1968) was modified for these analyses. A 0.1000 g sample was digested with 3 ml concentrated HF and 0.5 ml aqua regia (3:1 mixture concentrated HCl and RN03) in a stainless steel bomb with a teflon insert for 2 hours at 140oc. The samples were cooled, transferred to 50 ml polypropylene volumetric flasks, br'ought to volume using a saturated boric acid solution (6%), filtered, and the elements determined using an rcp Spectro-photometer (ARL-3400). '

Chemical Characteristics

Reaction. All soil suspension pH values were measured electrometrically using a pH meter. The pH values were measured in a 1:1 (weight basis) soil: distilled water (H70) , 1:1 soil:lN KCl (IN KCl) and 1:1 soil:0.01M CaC1 0 (CaC1 0 )

- L L suspensions.

Exchangeable Ca, Mg, K, Na. Exchangeable bases (Ca, Mg, Na, and K) were extracted by leaching with IN ammonium acetate buffered at pH seven as described by Metson (42). Solution concentrations were determined by atomic absorption. Standards were prepared in similar concentrations of ammonium acetate.

Exchangeable Al and H. Exchangeable H and exchangeable Al were determined using the method of Yuan as described hy the Soil Survey Staff (75)., The extracting agent in this procedure is IN KCl. This determination was made on all horizons having pH less than 7.0 in 1:1 soil:water suspension.

Extractable acidity BaClZ-TEA. The extractable acidity at pH 8.0 was determined by the method described by ~eech (1965). A 1:10 soil:BaC1

2-TEA sus

pension is prepared and allowed to stand overnight (the initial BaCr -TEA solution is buffered at pH 8.0). The suspension i~ then filtered an~ residue washed with an equal volume of the BaC1 2-TEA reagent. The filtrate is then titrated with 0.500N HCl to determine the change in the buffer capacity of the BaC1 2-TEA solution. Extractable acidity is determined by difference between buffer strength of the leachate and an equal volume of unused BaC1

2-TEA reagent.

29

30

Cation exchange capacity:

Effective CEC = exchangeable (AI + H) in IN KClextract + exchangeable (Ca + Mg + K + Na) measured in neutral normal NH

40Ac soil leachate.

Sununation of

Saturation

cations CEC = exchangeable (Ca + Mg + K + Na) determined by the NHHOAcmethod + extractable acidity determined by the BaCI

2-TEA procedure.

Soil used forexchangeableCa, Mg, K, and Na measurements is washed free of excess NH with ethyl

. alcohol. Sorbed NH4 is then displace~ by leaching with acidified 10% NaCI solution. The leachate is made alkaline with O.lN NaOH and the NH4 distilled into a 2% boric acid trap. The trapped ammonia is titrated with standard acid and CEC calculated on basis of acid required in the titration.

% Al saturation exchangeable Al x 100 effective CEC

% H saturati.on = exchangeableH x 100 effective CEe:;

% base saturation = exchangeable (Ca + Mg + K + Na) x 100 sum of cations CEC

Total carbonate as percent CaC03 • Samples having a soil suspension pH (in water) of 7.0 or greater were analyzed for total carbonates as CaC03 equivalent by the HCl digestion method described by the Soil Survey Staff (1972).

Free Fe. Free iron determinations were made according to the method described by Kilmer. In this method a sodium dithionite extraction is made on the whole soil. Reduction to ferrous iron is accomplished with stannous chloride. Solution concentration of Fe is determined by Atomic Absorption spectrophotometry.

Phosphorus. Phosphorus was determined by the Bray II method as outlined by Brupbacher, et al. (1968). The Bray II extracting solution is O.lN HCI and 0.03N NH4F.

SITE 1

This stop is located approximately 0.8 ~u. east northeast of the Slee represented by the morphological description and supporting data. The original site is now beneath the new Agronomy Department Building .on campus. In comparison, this alternate site does not overlook the escarpment from the loess mantled Prairie Terrace to the Mississippi River floodplain, is about 1 meter lower in elevation, and internal soil drainage is more restricted in and below the lower solum.

The Prairie Terrace is the most extensive and best preserved of the Pleistocene age terraces in Louisiana (Fisk and McFarlan, 1955). It lies about 7 meters above the adjacent Mississippi River Floodplain. Local relief in areas away from the escarpment is commonly less than 3 meters and regional slope is to the south at about 1 foot per mile (Kupfer, 1964). Streams draining the terrace flow into Lakes Maurepas and Pontchartrain, rather than the adjacent Mississippi River. Post-depositional erosion of the surface has been minimal and relict geomorphic features reflecting its origin are well preserved and not entirely masked by the loess mantle on its surface. Locally such features include abandoned channels of an ancestral Mississippi and associated natural levees and backswamp areas (Durham. 1964, Durham, 1967).

Most workers consider the Prairie Terrace a Sangamon interglacial stage deposit subsequently exposed during advancing Altonian glaciation (Saucier, 1974. 1976).' This places it at an appropriate age and time of subareal exposure to have received Roxana loess deposits which have not been definitely identified on its surface. Existing information indicates a marked thinning of the. Roxana loess in the Lower Mississippi Valley south of Crowley's Ridge in Arkansas. Further research is needed to determine if a small increment of this loess is present, but incorporated into the basal mixed zone of the Peoria 10esj4~ Som~ workers ha~e reco~:red or~anics at ~epth from ~ts section to old for L. datJ.ng (Otvos, 1980, A.L:t;ord and Kolb, 1983). Other's have considered the Prairie Terrace younger, Altonian through Farmdalian. Indicators supporting interpretations of a post-Sangamon age interpretation include: the high degree of preservation of depositional geomorphic features, moderate development of the buried soils it contains, high base status of modern soils developed in its surface. and recovery of datable 14C material from upper parts of the section by some investigators (Alford and Kolb, 1983). In addition, the surface mapped as a fluvial Prairie Terrace by Fisk (1938) has been identified as T2 by Delcort and Delcort (1977). Otvos (1980), and Alford and Kolb (1983) •

Cores taken at the site indicate a Memphis soil (Typic Hapludalf) with more restricted internal drainage than modal for the series. The local occurence of the Memphis soil is restrictred almost entirely to small, generally elongqte areas a fe~" yar~s wide adjacent to and paralleling the natural drainage ways or the escarpment to the lower Mississippi River alluvial plain. Their local occurence is one illustration of the "brown edge" effect that results from the improved internal drainage associated with these local differences in relief. Loring and Olivier soils (Typic and Aquic Fragiudalfs. respectively) occur locally at the site in areas that are wetter for longer periods and at shallower depths. Olivier and Calhoun (a Typic Glossaqualf) are the predominant soils developed in loess in the general area. Other associated soils developed in thick loess deposits include Deerford (Albic Glossic Natraqual£). Jeaneret,te (Typic Argioquoll). and Verdun and Bonn (Glossic Natraqualfs). The Dexter (Ultic Hapludalf) and Providence (Typic Fragiudalf) soils occur in areas where thin loess deposits contain an admixture of the underlying material throughout.

31

32

SITE 1

Prairie Terrace

Memphis Soil (fine-silty, mixed, thermic Typic Hapludalf)

Location: Baton Rouge, Louisiana on Louisiana State University Campus 90 meters South Southwest of junction of Highland Road and Tower Drive (elevation: approximately 12.5 meters).

The Memphis series is comprised of well-drained, moderately. permeable soils formed in Peoria loess deposits greater than approximately 1.25 meters thick.

Formation Soil

Horizon

Ap

Btl

Bt2

Bt3

Bt4

Depth (meters)

0.00-0.18

0.18-0.25

0 .• 25-0.51

0.51-0.91

0.91-1.32

Morphology

Brown (10YR 5/3)· silt; weak, fine and medium granular structure; friable; many medium and fine roots; many fine pores; slightly acid; abrupt smooth boundary.

Yellowish brown (10YR 5/4) silt loam; weak, fine and medium subangular blocky structure; friable; clay films on some peds and in pores; many fine roots; many medium and fine pores; medium acid; clear smooth boundary.

Dark brown (7.5YR 4/4) silt loam; moderate, medium and . fine subangular blocky structure; firm; slightly sticky, plastic;. many fine roots; many fine to medium pores; continuous clay films (10YR 4/3) on peds; strongly acid; gradual smooth boundary.

Dark brown (7.5YR 4/4) silt loam; moderate, medium subangular structure; friable; slightly slightly plastic; common fine thin discontinuous clay films surfaces; very strongly acid; smooth bound~ry.

blocky sticky; roots;

on ped gradual

Dark brown (7.5YR 4/4) silt loam; weak, medium subangular blocky structure; friable; slightly sticky; slightly plastic; few fine roots ; common medium and fine pores; thin discontinuous clay films on some peds; common, light gray

Bw 1. 32-1. 60

C1 1. 60-2.62

C2 2.62-3.38

C3 3.38-4.17

2Bt1b 4.17-4.42

2Bt2b 4.42-4.90

(10YR 7/2) silt coatings on many vertical ped faces; strongly acid; clear smooth boundary.

Dark brown (7.5YR 4/4) silt loam; weak, medium and coarse, sub angular blocky structure; friable; few fine roots; few medium and fine pores; few thin discontinuous clay films on some peds. Common light gray (10YR 7/2) silt coatings on many vertical ped faces; strongly acid; gradual smooth boundary.

Yellowish brown (10YR 5/4) silt; weak, coarse, subangu1ar blocky to prismatic structure; friable; common medium and fine pores; light gray (10YR 7/2) silt coatings on vertical faces of some peds; strongly acid; diffuse smooth boundary.

Yellowish brown (10YR 5/4) silt loam to 2.87 meters; silt below 2.87 meters; weak, coarse, sub angular blocky to prismatic structure; friable; common medium and fine pores; common light yellowish brown (10YR 6/4) silt loam bodies; clay content increases slightly with depth in lower one-half; strongly acid gradual smooth boundary.

Pale brown (10YR 6/3) silt loam; common, medium and fine, brownish yellow (lOYR 6/6) mottles. Weak to moderate. coarse subangu1ar blocky structure; friable; common medium and fine pores; strongly acid; clear smooth boundary.

Pale brown (10YR 6/3) silt loam; many, coarse, medium and fine brownish yellow (lOYR 6/6) mottles; weak to moderate, medium subangular blocky structure,. friable; common medium and fine pores; strongly acid; clear smooth boundary.

Pale brown (10YR 6/3) and brownish yellow (10YR 6/6) silty clay loam; moderate medium sub angular blocky structure; firm; sticky; plastic; common medium and fine pores; strongly acid.

33

34 SITE 1

Depth (meters) I

0.00-0. 18.-----/ I

0.51-0.91

1013

1m 1. 32-1. 60

sa

70

60 -

0) sa

.-ttl u 413

V')

~ 3:11

221

ud -B-1

Horizon ____ AP

-_Btl

--Bt2

--Bt3

~--BW

'----- Cl

Formation

I ~

'r-o Vl

I:: sO)

"'0 o E 0) I:: ..... I:: 'r-ttl ...., I:: o U

Vl Vl 0) o

ttl 'r-so 0)

0---

-0 0)

<1).,.-u s,.. ttl ::::::r ~..C! ~ <1)0)

1-1:: 'r- r-

0)1::0 or- or- U1 S-ttlO ''- ...., <1) n:! t::.-S-Ottl

0... U 0...

Figure 9' Clay-free particle size distribution (Coulter Counter and sieve) in a Memphis soil and underlying Paleosol on the Prairie Terrace in East Baton Rouge Parish, Louisiana.

o. O. O. O. O. 1. 1. 1. 2. 2. 2. 2. 3. 3. 3. 4. 4. 4.

Table 7~ Particle size distribution in a Memphis soil and underlying paleosol on the Prairie Terrace in East Baton Rouge Parish, Louisiana.

L Size Class and Particle Diameter (mm) Depth Horizonf Total Sand -

I I I Silt Sand Silt I Very Sand

(2.0- I i Clay Coarse Coarse Medium Fine Very fine

Tex-tural

(meters 0.05) 'I (0.05-

0.002) 1«0.002) 2.0-LO) (1.0-0.5) (0.5-0.25) (0.25-0.1 ) (0.1-0.05 ) class

00-0.18 liP I 6.7 I

84.5 1

8.8 18-0.25 Btl ! 4.8 79.1 16.1 ,

i 25-0. 51 1 Bt2 I 4.6 68.6 26.8 51-0.91 Bt3 : 4.6 70.6 I 24.8 , ! 91-1.32 Bt4 , 6.3 73.9 19.8 I 32-1. 60 Bw

, 8.2 78.4 13.4

60-1. 85 Cl 6.6 81.4 12.0 85-2.11 8.0 80.3 11.7 11-2.36 6.1 84.7 9.2 36-2.62 5.8 83.3 10.9 I 62-2.87 : C2 6.9 80.8 12.3 i 87-3.12! 6.0 I 83.6 10.4 12-3.38 : 5.6 I 83.0 11.4 I 38-3.66 C3 5.6 81.9 12.5 66-4.17 13.3 66.1 20.6 17-4.42 2Btlb 12.7 61.4 25.9 42-4.67 2Bt2b 14.0 57.5

I 28.5

67-4.90 1'1.2 53.8 31.0

I I

I I I I I

I

I j

Pet. of "- 2 ,~

I 0.1 0.3 0.5 0.0 0.1 0.2 , 0.1 0.1 0.1 I 0.0 0.1 0.1 I 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.1 0.1 0.0 0.1 0.1 0.0 0.0 0.1 0.0 0.1 0.1 0.1 0.1 0.1 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.1 0.1 0.5 0.3 0.1 0.1 0.2 0.1 0.1 0.2 0.1 0.0 0.1 0.1

I

0.4 5.4 0.3 4.3 0.3 4.1 0.4 4.2 0.1 6.1 0.1 8.1 0.1 6.4 0.2 7.8 0.1 6.0 0.1 5.6 0.2 6.6 0.1 5.7 0.1 5.4 0.5 5.0 3.2 9.1 3.4 8.9 3.9 9.7 4.6 10.5

,

\ I

i I

I I i I

12.6 16.5 14.9 15.3 11. 7

9.6 12.3 10.0 13.9 14.4 11. 7 13.9 14.8 14.6 5.0 4.8 4.1 3.5

w V1

36

Table 8. Profile distribution trends of Phyllosilicates in the clay-size fraction of a Memphis soil and underlying paleosol on the Prairie Terrace in East Baton Rouge Parish, Louisiana.

Mineral ComEonent Inter-

stratified Depth Soil Vermiculite and

(meters) Horizon Kaolinite Micaceous Smectite (Eedogenic) inter layered

0.00-0.18 Ap XXXXXXy xxxx: Xy'" .- xxx xxx 0.18-0.25 Btl 0.25-0.51 Bt2 xxxxxx xxxx. XXXYX xx xxx 0.51-0.91 Bt3 xxxxxx xxx' xXXxxxx x xxx 0.91-1.32 Bt4 xxxxxx xxxx XXXXxxx x xx 1.32-1.60 Cl xxxxxx xxxx XXXXxx~: x xx 1.60-1.85 xxxxxx xxxx xxXxxxx x xx 1.85-2.11 xxxxx xxxx' xXXXxxxx x xx 2.11-2.36 xxxxx xxxx xxxXxxxx x xx 2.36-2.62 xxxxx xxxx. xXXXXXXx x xx 2.62-2.81 C2 xxxxx xxxxx XXXXXlcc: xx 2.81-3.12 xxxxx xxxxx: XXXXXXxx xx 3.12-3.38 xxxxx xxxxx. xxxx:x:xxx xx 3.38-3.66 C3 ·xxxxx XXXX xxxxx:lO{xx xx 3.66-4.17 xxxx xxx;><:: xxxxxxxxxxx xx 4.17-4.42 2Btlb xxxx xxx: xxxxxxxxxx xxx 4.42-4.67 2Bt2b xxxx xxx xxxxxxxxxx xxx 4.67-4.90 xxxx xx xxxxxxxxxxx xxx'

Depth

(meters)

0.00-0.18 0.18-0.25 0.25-0.51 0.51-0.91 0.91-1. 32 1. 32-1. 60 1.60-1.85 1. 85-2.11 2.11-2.36 2.36-2.62 2.62-2.87 2.87-3.12 3.12-3.38 3.38-3.66 3.66-4.17 4.17-4.42 4.42-4.67 1.67-4.90

Horizon

Ap Btl Bt2 Bt3 Bt4 Bw C1

C2

C3

2Btlb 2Bt2b

pH In 1:1

su.~en8ion

H20 ~aC12 ll.NKCl

6.4 5.9 5.5 5.0 5.1 5.2 5.2 5.2 5.2 5.2 5.3 5.3 5.4 5.5 5.4 5.3 5.3 5.2

5.8 5.6 5.1 4.5 4.6 4.6 4.6 4.6 4.6 4.6 4.8 4.9 5.0 5.1 5.0 4.9 4.9 4.9

5.2 5.0 4.4 3.9 3.9 4.0 4,,0 4.0 4.0 4,.0 4.1 4.1 4.2 4.2 4.2 4.1 4.1 4.1

Ca

Table 9 Selected chemical characteristics of a Memphis soil and underlyin9 Paleosol on the Prairie Terrace in East Baton Rouge Parlsh, Louisiana

Exchangeable Mg I KINa Al H

I I I

Extract": able

acidity ca DaC1 2- effec- urn of TEA Itive ations

Saturation

Ai IH Fases

·-------:---milliequivalents!lOO grarn9----------,

---7.--

3.4

6.1 6.2 5.5 4.3 4.5 4.7 3.8 4.8 4.8 4.7 4.9 5.4 6.8 9.8

10.1 12.2

0.8

2.8 2.6 2.2 1.8 1.8 2.0 1.6 2.0 2.2 2.0 2.2 2.2 3.1 3.8 3.8 4.4

0.4

1.0 0.4 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.2 0.2 0.2 0.2 0.2

1),11 0.0 0.0

0.2 0.2 0.2 1.0 0.4 0.8 0.4 0.6 0.4 0.6 0.4. 0.6 1.2 0.4 1.1 0.2 1.0 0.0 1.2 0.0 0.9 0.0 0.5 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.3 0.0

0.2 0.2 0.2 0.3 0.1 0.2 0.1 0.2 0.2 0.2 0.2 O. :2 0.2 0.2 O '~ .<-

0.2 0.2 O 'I .f-

2.1

7.1 7.1 7.2 6.1 4.1 3.6 3.1 3.1 3.6 3.1 6.7 2.1 2.5 3.6 3.1 3.6

4.9

10.5 10.7 9.2 7.4 7.5 8.0 7.3 8.4 8.3 8.2 8.4 8.5

10.5 14.2 15.5 17.3

5.81

11.7 11.6 10.4 8.2 8.3 8.2 7.7 7.8 8.1 7.6 8.4 9.4

13.2 14.6 17.0 18.8

6.9

17.2 16.5 15.5 12.7 10.9 10.8 9.8

11.1 11.7 11.1 14.9 10.4 12.8 17.6 18.4 20.7

o o 2 2 9 3 8 1 8 2 8 1 7 2 5 2 2 2 o 2 o 2 o 2 o 2 o 1 o 1 o 1 o 1

68

58 56 53 51 62 66 68 72 69 72 55 79 80 79 83 82

I

I Ca/Nf, _ '[,tr. :(Exchan!;e- Organic tre~s free ,-i able) C COl Fe ·(!lr.,·.1 i

4.2

2.2 2.3 2.5 2.3 2.5 2.3 2.3 2.4 2.1 2.3 2.2 2.4 2.1 2.5 2.6 2.7

---_ .. _---

0.41

i 1. 23 I,

1. 42 '1.68 0.96 . 1.00 0.87 O~ 98 ' 0.76 ' 0.79 0.75 '

'0.76 . 0.76 '

iO.34 0.40 I

0 .. 39 0.30

222 170 130 132 185 265 292 300 295 282 290 315 294 320 100 85 47 40

LV -...J

Table 10. Whole-soil composition of nine elements and Ti/Zr ratio in a Memphis soil and underlying paleosols on the Prairie terrace in East Baton Rouge Parish, Louisiana.

I ,.

Depth Element Ratio (meters) Horizon Ca I Mg I K] Al L Fe.1 Si P ----J------~pm----- Ti Izr rri/Zr

I --------------------%------ ------------- --.. ----,.---

0.00-0.18 AP 0,,10 ! 0.01 I 1.21 2.44 0.95 27.96 802 2484 388 6.40 0.18-0.25 Btl 0.25-0.51 Bt2 0,,07 0.07 1.53 4.52 2.76 26.76 1186 3127 534 5.86 0.51-0.91 B"t3 0.08 0.08 1.44 4.25 2.69 24.43 1180 2789 556 5.02 0.91-1.32 B;t4 0.10 0.03 1.38 4.04 2.28 25.26 864 2672 365 7.32 1. 32-1.60 Bw 0.33 0.29 1.60 4.70 2.47 29.81 1042 2885 374 7.71 1.60-1.85 Cl 0.35 0.34 1.57 I 4.53 2.35 29.55 1038 2883 396 7.28 1. 85-2.11 0.40 0.32 1.56 I 4.59 2.28 29.40 945 3032 399 7.60 2.11-2.36 0.42 0.32 1.54 4.45 2.32 29.08 1000 2960 428 6.92 2.36-2.62 0.40 0.31 1.65 4.63 2".40 29.86 970 3145 429 7.33 2.62-2.87 C2 0 .. 52 0.38 1.64 4.68 2.26 28.97 917 ~975 422 7.05 2.87-3.12 0.09 0.02 1.34 3.14 1.82 24.59 717 2406 342 7.03 3.12-3.38 0.08 0.01 1.39 3.30 1. 76 24.36 659 ~280 . 331 6.89 3.38-3.66 C3 0.07 0.01 1.40 3.42 1.90 25.97 738 ~385 377 6.32 3.66-4.17 , 0.11 0.01 0.77 3.00 1.48 27.09 321 ~561 342 7.49 4.17-4.42 2Bt1b 0.15 0.01 0.57 3.47 1.61 27.84 242 n55 309 8.92 4.42-4.67 2Bt2b 0 .. 13 10.01 0.33 3.63 1.80 29.20 293 3161 311 0.16 4.67-4.90 0.25 I 10.11 0.54 4.77 2.10 35.44 317 3775 322 1.72

I

I ! I

I I I

I I I

I I I i , i

i I

I i

\

w 00

SITE 2

This stop is approximately 50 meters from the site represented by the accompanying morphological description and supporting data. The site is on the Intermediate Terraces of Snead and McCulloh (1984). Its surfa~e is about 10 meters higher than that of the Prairie Terrace, visible to the south from the site. Local relief is greater than on the Prairie Terrace and regional slope is to the south at about 5 feet per mile (Kupfer, 1964). Locally, most of the drainage from its surface is to the Mississippi River by way. ot the south~est trending Bayou Baton Rouge and Cooper Bayou. Cypress Bayou to the east drains parts of the area into Lake Maurepas.

The Intermediate Terrace (Snead and McCulloh, 1984) identification is preceded by Irene (Durham et al., 1967), Montgomery (Russell and Morgan, 1964; Fisk, 1940). Oberlin (Doering, 1956) and Second Terrace (Fisk et al.,1938). The Yarmouth interglacial is the time of deposition most frequently indicated for the terrace. Saucier (1974) discussed regional distribution and characteristics of the Montgomery Terrace and considered it to be Yarmouth in age. He recognized the apparent inconsistency between the degree of preservation of the surface and the long time period since its presumed deposition. Fisk and McFar1an (1955) considered it to be a Sangamon age deposit. Discussionqby Durham (1967) and Rosen (1969) emphasize the importance of faulting in landform development. Structural movement along faults in the area and the effect on erosion and deposition may have influenced its position and landscape on the terrace.

Peoria and Pre-Peoria loess, each burying identifiable paleosols, occur on the terrace surface. Thus, it has been subareally exposed longer than the Prairie Terrace which only has the Peoria loess. The Pre-Peoria loess was deposited on a surface containing distinct soil profiles. The time of depositidn of the Pre-Peoria loess has not yet been established.

Major soils on the terrace are Olivier and Loring (Fragiudalfs) , Calhoun and Frost (Glossaqualfs) and Deerford and Verdun (Natraqualfs). Olivier is by far the predominate soil near the site. The better drained Loring soils occupy relatively small areas on the highest, convex and best drained sites. Calhoun and Zachary (Typic Albaqualf) soils are on the larger flats and in slightly depressional areas.

Buntley et al. (1977) indicated that fragipans form at the Roxana-Peoria loess contact zone in soils developed in thick loess deposits in West Tennessee. In Arkansas, West.et al. (1977) described similar fragipans in soils developed entirely in Peoria loess. In Louisiana, soils formed in thick loess deposits and having fragipans appear to have developed in a single loess deposits. However, they also form at many loess-loess and loess-nonloess contact zones in thinner loess deposits. Fragipan formation in deposits lacking loess is also common.

The fragipan in the Olivier soil has cross sectional area and dimensions of the brown brittle bodies that are near the minimum allowed by definition. This is believed to reflect on advanced rather than incipient stage in frag:i,pan development.

39

40

SITE 2.

Irene -Terrace

Olivier Soil (fine-silty, mixed, thermic Aquic Fragiuda1f)

Location: East Baton Rouge Parish, Louisiana; East of highway 61 and south of Barnett Road in SW!t;, SW!t;, NE!t;, Survey No. 79; T5S; R1W (elevation: approximately 26.8 meters).

The Olivier series is comprised of somewhat poorly drained, slowly permeable soils formed in Peoria loess deposits more than approximately 1.25 meters thick or where Peoria loess deposits overlie older (Roxana?) loess deposits at depths within the modern soil solum.

Formation

r-I • ,-j

a rn

Soil Horizon

Ap

E

Btl

Bt2

Depth (meters)

0.00-0.20

0.20-0.38

0.38-0.58

0.58-0.81

Morphology

Grayish brown (10YR 5/2) silt; weak medium granular structure to structure1ess; friable; common medium and· fine roots; common med ium and fine black and brown concretions; slightly acid; abrupt smooth boundary •

Pale brown (10YR 6/3) silty loam; few fine faint yellowish brown (10YR 5/4) and grayish brown (10YR 5/2) mottles; weak mediumsubangu1ar blocky structure; friable; common fine roots; coronion fine and medium pores; few medium and fine black and brown concretions; very strongly acid; clear smooth boundary.

Yellowish brown (10YR 5/4) silt loam; moderate medium subandu1ar blocky -structure; friable; few fine roots; common fine and medium pores; some pores coated with clay films, some with black stains; thin discontinuous clay films on ped~; black coatings on some ped faces; thin discontinuous silt coatings on some ped faces; fe\y medium and fine black, brown. and yellowish red concretions; very strongly acid; clear wavy boundary.

Yellowish brown (10YR 5/6) silt loam; few to common medium and fine distinct yel19wish red (5YR 4/6). grayish brown (10YR 5/2), and brown (10YR 4/3) mottles; moderate medium subangu1ar blocky structure; firm; few fine roots; common fine and medium pores coated with

0.81-1.07

Bx2 1.07-1.42

Bx3 1.42-1.91

Bw1 1.91-2.41

thin clay films and black stains; thin discontinuous clay films and black stains on peds; thin silt coatings on many peds; common medium and fine black, brown and yellowish red concretions; very strongly acid; clear wavy boundary.

Yellowish brown (iOYR 5/4) silt loam; common fine and medium faint grayish brown and brown mottles; moderate medium and coarse subangular blocky structure; Bx portion is firm and brittle; E' portion is friable; few fine roots along Bx ped faces; common fine and medium pores coated with clay films and black stains in Bx part; thin discontinuous clay films and black stains on ped faces; common medium faint light brownish gray (lOYR 6/2) silty seams; few medium and . fine black. brown and yellowish red concretions; very strongly acid; clear irregular boundary. .

Yellowish brown (10YR 5/4) silt loam; common fine distinct grayish brown and light gray mottles; moderate coarse subangular blocky structure; very firm and brittle in about 75 percent of the horizontal cross section, remainder is friable; few fine roots between prisms; common fine and medium pores in peds coated with clay films and black stains; thin discontinuous clay films and black stains on peds; thin discontinuous silt coats. and (lOYR 6/2)

thick light silty clay

brownish gray loam vertical

seams between prisms; common medium black and brown concretions; very strongly acid; diffuse irregular boundary.

Yellowish brown (10YR 5/6) silt loam; common medium distinct gray (5Y 6/1) silty clay loam vertical seams between peds; weak very coarse subangular blocky structure; firm; common fine pores coated with light gray clay films; few medium black concretions; strongly acid; gradual wavy boundary.

Light yellowish brown (10YR 6/4) silt loam few fine faint yellowish brown (lORY 5/8) and light brownish gray (10YR 6/2) mottles; weak coarse subangular

41

42

Bw2

2Bt1b

2Bt2b

2Bt3b

2Bwb

2.41-2.90

2.90-3.38

3.38-4.17

4.17-5.03

5.03-6.15

blocky structure; friable; common vertical light brownish gray (10YR 6/2) silt seams; common medium and fine black and brown concretions; strongly acid; diffuse wavy boundary.

Yellowish brown (10YR 5/6) silt loam; otherwise same as Bw1 at 1.90-2.41 meters.

Brownish yellow (10YR 6/6) silty clay loam; moderate medium sub angular blocky structure; firm; peds coated with yellowish brown (10YR 5/6) clay films; few fine and medium distinct strong brown (7.5YR 5/6) mottles; few thin light brownish gray (10YR 6/2) vertical, gray silt seams; strongly acid; gradual smooth boundary.

Brownish yellow (lOYR 6/6) silty clay loam to 3.63 meters; silt loam below 3.63 meters; moderate medium subangular blocky structure; firm, reddish yellow (7.5YR 6/6) clay films on many ped suri'aces and in pores; common distin~t medium light brownish gray (lOYR 6/2) and few fine and medium prominant red (2~5YR 4/6) mottles; few fine and medium black and brown concretions; strongly acid; gradual smooth boundary.

Light brownish gray (10YR 6/2) and brownish yellow (10YR 6/6) ~;lt loam;. moderate to weak medium sub angular blocky structure; firm; thin discontinuous reddish yellow (7.5YR 6/6) clay films on peds and in pores; common distinct strong brown (7.5YR 5/8) mottles; strongly acid; gradual smooth boundary.

Brownish yellow (10YR 6/6) to reddish yellow (7.5YR 6/6) silty clay loam; moderate to weak medium subangular blocky structure; firm; common medium and fine light brownish gray (10YR 7/1) mottles; thin discontinuous clay films on some peds and in pores; black coatings on some peds; few small and medium black and brown concretions; strongly acid; clear smooth boundary.

3Btb 6.15-6.80 Light bro'Ymish gray (lOYR 6/2 to 2. 5Y 6/2) silty clqy loam; common, medium and fine strong brown (7.5YR 5/6) mottles; moderate, medium sub angular blocky structure; very firm; strongly acid.

43

44

1l1li

911

l1li

78

£III Q) r-

~J rc! U

V)

~

I; J .1

SITE 2·

0.38-0.

0.81-1.07

1. 42-1. 73

1.91-2.16

2.41-2.64

2. 90-3.1~5 -./

6. 15-6.~

6.45-6.'"'-'--___

tl t2

X/E'

X2

X3

wl

2Bt 1 b

3Btb

Formation

s::: S-Q)

""C 0 E

0'> s:::

'r-s:::

'0-

ttl +-> s::: 0 u VI VI Q) 0

ttl 'r- • s...-o .... Q)O

0... VI

c-o VI o Q)

ftl 0...

-0 VI Q) Vl·'-Q) S-0:::1 r- ..0

ttl 0'> 'r- s::: s-.r-os::: W'r

n.- fO I +'

(1)1::: $..0

0.. U

'r-s...

(1):::1 U ..0 ttl S-O'> S- I::: • QJ -..- r--

----' I- s::: 0 ',- VI

(I) ttl 0 s::: +-> (I) (l)S:::.S-Oftl

...... U 0..

Figure ]0 Cldy-free particle size distribution (Coulter Counter and sieve) in an Olivier soil and underlying Paleosols on the Irene Terrace in East Baton Rouqe Parish. Louisiana

Table 11. Particle size distribution in an Olivier soil ,,'-TId underlying paleosols on the Irene Terrace in East Baton Rouge Parish, Louisiana.

Depth )H~rizon~ 1 !

(meters

o . 00-0.201' 0.20-0.38 0.38-0.581 0.58-0.81,1 0.81-1.07 1.07-1. 42 1 1.42-1. 73' 1. 73-1. 91 1.91-2.16 2.16-2.L,l

I 2.41-2.64·· 2.64-2.90 2.90-3.15 3.15-3.38 3.38-3.63 3.63-3.89 3.89-4.17 4.17-4.47 4.47-4.78 4.78-5.03 5.03-5.28 5.28-5. 54 1

5.54-5.84\ 5.84-6.15 I 6.15-6. 45 1 6.45-6.81

I

AP E Btl Bt2 Bx/Eli

; I Bx2 . Bx3 I

Bw1 I Bw2

2Btlb

l""

2Bt2b ,

2Bt3b

2Bwb I

3Btb I

Sand C2.0-0.05)

10.2 4.1 3.2 3.5 4.4 4.2 4 ..., • I

4.3 6.9 5.8 5.3 3.8 2.4 3.0 2.9 3.0 3.0 5.5 4.9 5.8 5.0 5.2 4.6 6.2 8.5 6.9

ToEa1 I I I I

Silt (0.05- I Clay I

10.002) I «0.002) I I r

i I I 83.4 I 6.4

74.6 i 21.3

I 70.2 26.6 76.5 20.0

I 74.5 21.1 76.8 19.0 76.1 19.2 80.2 I 15.5

I 76.1 17.0

I 75.8 18.4 I 76.5 18.2

75.5 21.7 66.7 30.9 67.8 29.2 69.9

I 27 .2

72.1 24.9 72.9 I 24.1 72.1 I 22.4 71.0 24.1 70.0 24.2 76.3 29.7 65.8 29.0 i 64.7 30.7 6.0.7 I 33.1 58.0

! 33.5

55.9 37.2

I I j

I

Size Class and Particle Diameter (rom) Sand ,

I I

Silt I Sand Very Tex-

Coarse Coarse Medium Fine Very fine I tural :2.0-l.0)I O .O- O,5) (0.5-0.25) (0.25-0.1) (0.1-0.05 ) class

Pct. of "- 2 lULU

0.4 0.6 1.8 1.4 6.0 8.2 s; 0.1 0.1 0.1 0.2 3.7 18.2 s;1 0.0 0.0 0.1 0.1 3.1 21. 9 s;l 0.0 0.1 0.1 0.2 3.2 21.8 s i 1 0.0 0.2 0.2 0.2 3.8 16.9 sil 0.0 0.1 0.2 0.2 3.7 18.3 sil 0.0 0.1 0.2 0.2 4.2 16.2 sil 0.0 0.1 0.2 0.3 3.7 18.6 sil 0.7 0.5 0.5 0.6 4.6 11.0 sil 0.6 0.6 0.5 0.6 3.5 13.1 sil 0.3 0.4 0.4 0.6 3.6 14.4 5;1 0.1 0.1 0.2 0.5 3.0 19.9 s i1 0.0 0.0 0.1 0.3 2.0 27.8 si cl 0.0 0.0 0.1 0.2 2.7 22.6 sicl 0.0 0.1 0.1 0.2 2.6 I 24.0 si cl 0.0 0.1 0.1 0.2 2.7 I 24.0 sil 0.0 0.1 0.1 0.2 2.8 24.3 sil 0.0 0.1 0.1 0.4 5.0 13.1 sil 0.0 0.1 0.1 0.3 4.6 14.5 sil 0.1 0.1 0.1 0.3 5.3 \12.1 si1 0.0 0.0 0.1 0.2 4.8 13.1 sicl 0.0 0.0 0.1 0.3 4.9 12.6 sicl 0.0 0.0 0.1 0.2 4.4 14.1 S i cl 0.0 0.0 0.1 0.3 5.9 9.8 s; cl 0.0 0.1 0.1 0.4 8.1 6.8 s; cl 0.0 0.0 0.1 0.4 6.5 8.1 sicl

I I

.,[:'-

I \.Jl

Table 12. Profile distribution trends of Phyllosilicates in an Olivier soil and underlying Paleosols on the Irene Terrace in East Baton Rouge Parish, Louisiana.

Mineral ComEonent Interstratified

Depth Soil Vermiculite and (meters) Horizon Kaolinite Micaceous Smectite (Eedogenic) interlayered

0.00-0.20 Ap xxxxxxxx xxx: xx xx xxxxx 0.20-0.38 E xxxxxxxx xxxx. xx x xxxxx 0.38-0.58 Btl xxxxxxx xxxx. xxx x xxxxx 0.58-0.81 Bt2 xxxxx xxxxxx: xxxx x xxxx 0.81-1.07 Bx/E' xxxxx xxxxxx xxxxx xxxx 1.07-1.42 Bx2 xxxx xxxxx xxxxxxx xxxx 1.42-1.73 Bx3 xxxxx xxxx· xxxxxxxx xxx 1.73-1.91 xxxxx xxxx: xxxxxxxx xxx 1.91-2.16 Bw1 xxxxx xxxx xxxxxxxx. xxx 2.16-2.41 xxxxxxxx xx xxxxxxx xxx 2.41-2.64 Bw2 xxxxxxxxxxx x xxxxx xxx 2.64-2.90 xxxxxxxxxxxx tr xxxxx xxx 2.90-3.15 2Bt1b xxxxxxxxxxxx tr xxxx xxxx 3.15-3.38 xxxxxxxxxxxxx tr xxx xxxx 3.38-3.63 2Bt2b xxxxxxxxxxx tr xxxxx xxxx 3.63-3.89 xxxxxxxxxx tr xxxxxx xxxx 3.89-4.17 xxxxxxxxxxx xxxxx xxxx 4.17-4.47 2Bt3b xxxxxxxxxx xxxx xxxx 4.47-4.78 xxxxxxxxxxxx xxxx xxxx 4.78-5.03 xxxxxxxxxxxxx xxx xxxx 5.03-5.28 2Bwb xxxxxxxxxxx tr xxxxx xxxx 5.28-5.54 xxxxxxxxx· tr xxxxxxx xxxx 5.54-5.84 xxxxxxxx tr xxxxxxxx xxxx 5.84-6.15 xxxxxxx x xxxxxxxx xxxx 6.15-6.45 3Btb xxxxx xx xxxxxxxxx xxxx 6.45-6.81 xxxxxx ·xx xxxxxxxx xxxx

-+'(J\

o o o o o 1 1 1 1 2 2 2 Z 3 3 3 :3 4 4 4 5 5 5 5 6 6

Depth

;) -

O' 8 8 :1 7 2 3 1 6 1 4 a 5 8 3 9 7 7 8 3 8 4 4 5 5 1

Horizon pH In 1:1

suspension H2 O f-aC1 2 NKC.l I

AP 6.3 5.8 5.1 E 14.9 4.4 3.9 Btl 4.9 4.2 3 -r .1

Bt2 1 I 4.9 4.2 3 -r .1 Bx/E 5 .. 0 4.3 3 -r .1 Bx2 5.0 4.3 3.6 Bx3 5.1 4.5 3 -r .1

5.2 4.6 3.8 BWl 5.3 4.8 3.9

5.4 4.8 4.0 8W2 5.3 4.8 4.0

5.3 4.8 4.1 2Btlb 5 1 . .- 5.0 4.1

5.4 5.0 4.2 2Bt2b 5.3 4.9 4.2

5.2 4.9 4.1 5.2 4.9 4·.2

2Bt3b 5.2 4.9 4 ., .<-5.3 5.0 4.3 5.3 5.0 4.2

2Bwb 5.3 5.0 4.2 5.5 5.2 4.1 5.2 5.1 4 ') .<-

5.4 5.2 4.3 3Btb 5.3 5.3 4.4

5.4 5.3 4. :~

Table 13 Selected chemical characteristics of an Oliver Soil and the underlying Palesols on the Irene Terrace in East Baton Rouge Parish, Louisiana

j'Extract Cation exchange

E;{changeable

I Mg I KINa I Al I H

I able

acidity I ~-r~-~~J 3aC11- c< , ._. C I TEA Itive

Saturation um of- I I

Cain,; '" ExCr.

(Exchange-IOrganlc I Fre'i's 'hQf'! i'-Ca

2 .. 0 0.8 1.8 2.1 1.2 3.1 La 3.0 LO 3.0 1.1 4.0 3 .. 2 4.5 3.4 4.1 3.9 4.2 3.1 3.3 3.8 3.8 4.4 3.8 5.2 4.1 6.8 5.1 6.0 4.6 5.8 4.5 5.3 4.0 4.1 3.2 5.4 4.0 4.7 3.4 6.0 4.6 6.5 4.8 7.1 5.4 8.2 5.6 8.7 6.2

11.9 8.0

I I

milliequivalents, /100 gramg---0.1 0.1 0.1 0.2 0.2 0.3 0.2 0.3 0.1 0.3 0.2 0.4 0.1 0.5 0.1 0.9 0.1 0.4 0.1 0.3 0.1 0.4 0.1 0.4 0.1 0.4 0.1 0.7 0.1 0.4 0.1 0.5 0.1 0.4 0.1 0.4 0.1 0 .. 4 0.1 0 .. 5 0.1 0 .. 5 0.1 0,.4 0.1 0 .. 5 0.1 0 .. 4 0.1 0..4 0.2 0 .. 6

I

0.0 0.2 1.8 0.3 4.2 0.4 3.5 0.0 2.7 0.3 2.0 0.2 0.8 0.3 0.2 0.4 0.2 0.3 0.0 0.4 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.7 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.2 0.0 0.2

I 3.1 5.1 9.7 8.2 7.2 6.7 5.1 2.5 1.0 1.5 1.5 1.5 1.5 1.5 1.5 2.5 2.0 1.5 1.0 1.5 2.5 2.5 3.1 3.6 3.1 4.1

3.1 6.3 9.4 8.0 7.4 7.9 6.2 9.1 9.1 7.2 8.3 8.9

10.0 12.9 11. 3 11.1 10.0 8.0

10.1 8.9

11.4 12.0 13.3 14.5 15.6 20.9

ations Al H

i. 5.0 6.0 0 6 8.3 9.3 29 5

11.6 15.5 45 4 9.7 12.7 44 0

10.1 11. 6 36 4 9.8 12.4 25 3

11.0 13.4 8 5 10.3 11.0 2 4 9.9 9.6 2 3 9.4 8.3 0 6 9.5 9.6 a 2 9.4 10.2 0 2

11.5 11.3 0 2 12.0 14.2 0 2 12.4 12.6 0 2 11.8 13.4 0 2 9.6 ll.8 0 2 9.6 9.3 0 2

10.2 10.9 a 2 9.9 10.2 0 2

. 13.9 13.7 0 2 I 13.8 14.3 0 2

15.4 16.2 0 1 18.4 17.9 0 18.8 18.5 0 1 20.8 24.8 0 I 1

48 45 31 35 38 46 62 77 90 82 84 85 87 89 88 81 83 84 91 85 82 82 81 80 83 84

able) C ICO l 'Fe '(l1ril',ll', i I

2.5 0.9 0.4 0.3 0.3 0.3 0.7 0.8 0.9 0.9 1.0 1.2 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.4 1.3 1.4 1.3 1.5 1.4 1.5

-------~ I r;o"

0.22, 9 , 0.65 . 2 '0.78' 20 '0.81118 ,0.80' 2 i 0.69 I 10 0.62: 31

iO.42; 42 0.21 28

:0.28: 16 iO.30, 15 '0.41110 0.62 I 2

; 0.68 I

0.42 ; 0.21 : 0.44 I '

[' 0.38' ,0.49 I : 0.48 I : 0.221 4 . 0.22 I 4 0.12 ! 1\

i 0.24 I 5

I 0.19 i 6 0.10 I 3

.p'-l

Table 14. Whole-soil composltion of nine elements and Ti/Zr ratio in an Olivier soil and underlying paleosols on the Irene Terrace in East Baton Rouge Parish~ Louisiana.

Depth r ---1 ,

Element Ratio (meters) Horizo

I -----------------K I Al L Fe I, Si -~--J-----l-----bpm----- I--~=--l~~ tri/Zr ---%------ ------~------I --T---~-

, !

0.00-0.20 I lAP 0.11 0.08: 1 0.20-0.38 E 0.09 0.22 1 0.38-0.58 I Btl 0.05 0.27 1 0.58-0.81 I Bt20.06 0.19 1 0.81-1.07: Bx/E' 0.11 0.33 1 1.07-1.42 I Bx2 0.14 0.21 1 1.42-1.73 Bx3 0.16 0.17 1 1.73-1.91 0.30 0.271 1 1.91-2.16 Bw} 0.19 0.17 0 2.16-2.41 0.13 0.10 0 2.41-2.64 Bw2 0.07 0.07 0 2.64-2.90 0.04 0.05 0 2.90-3.15 2Bt1b 0.03 0.05 I 0 3.15-3.38 0.02 0.03 I 0 3.38-3.63 2Bt2b 0.04 0.03 0 3.63-3.89 0.10 0.10 0 3.89-4.17 0.02 0.02 0 4.14-4.47 2Bt3b 0.01 0.01 I 0 4.47-4.78 0.01 0.01 I 0 4.78-5.03 0.01 0.01 0 5.03-5.28 2Bwb 0.00 0.00 I 0 5.28-5.54 0.01 0.08 0 5.54-5.84 0.17 0.191 0 5.84-6.15 0.12 0.12 0 6.15-6.45 3Btb 0.18 0.20 " 0 6.45-6.81 0.26 0.35 0

I

I I

,06 I 2.59 0.95 32.53 150' ; 2473 503 4.9 29 i 4.10 2.06 29.65 264 ; 2888 584 4.9 , 30 4.80 2.80 27.19 467 : i 3071 623 4.9 55 4.97 2.82 30.65 461 ! 3197 651 4.9 Lf7 4.81 2.69 38.25 370 j 3106 655 4.7 32 4.43 I 2.31 26.13 398 ! : 2928 673 4.4 ~}O 4.22 2.20 37.46 490 I 2956 791 3.7 I 31 4.22 1.85 29.71 342 i 3024 814 3.7 76 3.35 1.53 31.52 213 I 3295 787 4.2 59 3.22 1.38 31.65 184 ! 3158 747 4.2 37 2.86 1.38 30.11 i

3584 807 4.4 181 I 18 3.03 1.59 30.64 182 I i 3746 820 4.6 10 3.62 2.13 28.18 184 I 3905 810 4.8 12 3.64 2.00 27.65 145 : 3899 758 5.1 28 3.23 1.68 27.52 H2 i 3464 736 4.7 26 3.40 1.37 30.30 125 i 3908 779 5.0 06 2.69 1.57 26.70 101 1 2975 593 5.0 00 2.29 1.28 27.01 67 I ' 2955 569 5.2 00 3.03 1.60 26.97 104 3202 595 5.4 I

1.61 27.59 128 2965 576 02 I 2.65 5.1 00 I 2.84 1.48 24.42 63 2939 492 6.0 02 I 3.43 1.33 28.43 123 3597 627 5.7 14 3.98 1.49 28.78 148 3836 677 5.7 19 \ 4.23 1.91 30.23 115 4044 697 5.8 27 ' 4.44 1.99 31:18 145 4024 605 6.7 52 5.23 2.07 28.15 214 3627 483 7.5

I I

l

I 1

I ,

~ 00

SITE 3

This stop is located approximately 15 Km north of the site represented by the accompanying morphological description and supporting data. The original site in Lafayette Louisiana is now a housing development area. Both sites are situated on the eastern edge of the Prairie Terrace and overlook the escarpment to the lower loess-covered surface and alluvial plain. The loess on the lower surface will be observed at site 4. In comparsion, the alternate site 1s on a more sloping landscape than the original (1 to 5 versus les~ than 1 percent). These sites are otherwise quite similar.

The loess-covered part of the Prairie Terrace west of the Mississippi River can be subdivided into two zones (Bernard et al., 1965; Howe et al., 1933; Saucier, 1974). The area at the sit~ is underlain by an upper deltaic plaJn or lower alluvial plain of the Mississippi River. This zone corresponds approximately to the region east of the Vermil ion River and Louisiana highway 182. The region described is characterized by a distinctive north-south trending meander belt topography in which a number of Prairie age Mississippi River courses are apparant. West of this area is a reI ict deltaic plain of the Red River characterized by many segments of southwest trending meander belts, extraordinarily flat topography, and predominately clayey deposits. The relationship between thickness of the loe~s on the Terrace and distance from the floodplain along one nearby transect is shown in Figure 11. Important relationships between loess thickness and some of the modern soils on the Terrace are illustrated in Figure 12.

The Memph is soi I (Typ i c Hap I uda I f) compr i ses a I arger port i on of the Pra i r i e Terrace surface than a II other so i I s comb i ned in an area of severa I Km 2

in t~e vicinity of the site. This area is unique'in that the Memphis soil occupies extensive areas having 0 - 1 percent slopes in soil bodies that may be several Km2 in size. Frost soils (Typic Glossaqualfs) occur in the wetter areas in association with Coteau (Glossaquic Hapludalf) in this same landscape.

Major soil association patterns in the area reflect the loes~ thickness and distribution. For example, from east to west on the Terrace (in the direction of thinning loess-Lafayette to Crowley, La.) one crosses five major soil association areas that occur as relatively narrow elongate north-south trending bands and enters a sixth and more extensive soil association. These are identified, from east to west, as Memphis - Frost, Coteau - Frost, Patoutville - Frost, Patoutville -Jeanerette, Jeanerette - Patoutville, associations developed in loess and the Crowley - Midland association developed in the Prairie formation.

Soils containing fragipans are not mapped in the Peoria loess deposits on the P~airie Terrace west of the Mississippi River. Small areas within bodies of the Coteau soil may, in places, have horizons that meet the criteria for fragipans. The Patoutville soil may also have a thin horizon that, although not a fragipan, has some of the 'brittleness ' characteristic associated with fragipans. Definitive for the Coteau series in the presence of "Fragipan - like" bodies completely surrounded by E horizon material and overlying a 8t horizon.

The Jeanerette soils are quite similar In appearance to Tjplc Argiaquolls developed in parts of the midwestern United States; Depths to secondary carbonates range from about 30 to 50 cm. Thickness of the zone containing carbonates is typically about 40 cmo These soils occupy low and/or broad flat landscape positions. The secondary carbonates form in the zone of fluctuation of the top of a seasonal water table present from late November or early December through April in most years (Qualls, 1984).

figure 11. Loess thickness and diistribution observed in an East-West transect in Lafayette Pa ris h, Louis iana.

Loess

Mixed / Loess -non loess

--, . _ ...

"..

.;'

." .. . ' , , " I

1 I

I 8

~ FF' r- F , rr-i j i ,

50 20 10.0 5.0

./

~ /

~I'

, , 1'0' • · 'u's 2.0

Distance in miles from 'Bluff' (log scalel

4

3 I

V) ~

CD --CD

S V) V)

CD 2 c: ~

~ .r=.

~ l-V) V)

CD 0 --'

~l

~O

V1 o

Figure 12. Schematic of relationships between modern soils and loess thickness on the Prairie Terrace in the Lafayette-Crowley area in Louisiana.

Note: (1) Base of reference is apparent contact between loess and more clayey Prairie Terrace formation.

(2) Loess thicknesses greater than 1 meter are based on data from transects; thickness at lesser depths are extrapolations.

(3) Not shown is the small effect the admixed zone has in increasing the apparent depth to the contact with the underlying material.

'4.0

III I-<

Memphis, Coteau, Acy, etc., soils developed in thick loess deposits .3.0 ~

Cro"l11ley, Mowat a , etc., soils deve loped in Prairie Terrac,s formation

Jeanerette, Patoutville, etc., soils developed in mixed loess-Prairie Terracel deposits I

f

-. ........... . ..............

........... .., ........... . ............... .. "' ........... . 'Oo.... ~ ................. .. ................ ................... '. . ................ .. .. "' ........... . .. 0 ........... .. .............. ............. ~~~~s~:~~

.0

<u ~

I: .... .D III <u a ~ {J ..... ~ ~

III ID <u

LO ;3

... -.::.'::.-: : ;;;;;,-,-;;:-, •. :.-.... -; .• -;-::-,~-: ;'-.~~ .. -:'~_._.~::_~_.~.~ ~_:_.~:.~~._._:_::._._._;XC~i.G~.~;:~.:):::;~;~:::~.=:~~~~;~;~(~:;~(:.::<~:;.i:~)~i:;~i:;>rO. 0

90~0 45 ~:D"I 315 36 T 2~ -10 15 fo 5

Distance in Kilometers from 'nluff'

;~ ~

~ ,_i-

~

VI f-'

52

SITE 3

Loess-Covered Prairie Terrace

Memphis soil (fine-silty, mixed, thermic Typic Hapludalfs)

Location: Lafayette Parish, Louisiana; SW!t;. NE!t;, NW!t;, NW!t; of E~ of W~ of Survey No. III,T9S., R 5E.; in city of Lafayette, La. (elevation: approximately 13 meters).

The Memphis series is comprised of well drained, moderately permeable soils formed in Peoria loess deposits greater than approximately 1.25 meters thick.

Formation

rl 'M 0 Ul

I::l H (])

'"d 0 13 OJ) I::l

'M I::l

'M til

.1-1 I::l 0 C)

(I)

Ul (]) 0 rl

til • .-1 H 0 (])

P-t

Soil Horizon

Ap

Btl

Bt2

Bt3

Bt4

Depth (meters)

0.00-0.17

0.17-0.30

0.30-0.48

0.48-0.81

0.81-1.42

Morphology

Dark grayish brown (10YR 4/2) silt; weak, fine granular structure; friable many medium and fine roots; many fine pores; common, brown to black concretions; strongly acid; abrupt smooth boundary.

Brown (7.5YR 5/4) silt loam; moderate, medium subangular blocky structure; firm; common fine roots; common fine· pores; continuous clay films on most ped surfaces; very strongly acid; clear smooth boundary.

Dark brown (7.5YR 4/4) silty clay loam; moderate, medium sub angular blocky structure; firm; continuous clay films on peds and in pores; common fine roots; common fine pores; very strongly acid; gradual smooth boundary.

Dark brown (7.5YR 4/4) silt loam; moderate, medium subangular blocky structure; firm; thin clay films on most peds; few fine roots; common fine pores; very strongly acid; gradual smooth boundary.

Brown (7.5YR 5/4) silt loam; weak. medium to coarse, subangular blocky structure; friable; thin, discontinuous clay films 9n peds; few fine roots; common fine pores; strongly acid; diffuse smooth boundary.

Bw

C1 2.03-3.55

C2 3.55-4.16

2Bt1b 4.16-4.47

2Bt2b 4.47-5.20

Brown (7.5YR 5/4) silt loam; weak, coarse subangular blocky structure; friable; common fine pores; strongly acid; diffuse smooth boundary.

Yellowish brown (10YR 5/4) silt loam; structureless; massive; friable.; common fine pores; strongly acid; gradual smooth boundary.

Pale brown (10YR 6/3) silt loam; con~on, medium, faint light brownish gray (10YR 6/2) and yellowish brown (10YR 5/4) mottles; structureless; massive; friable; common fine pores; medium acid; clear smooth boundary.

Light brownish gray (10YR 6/2) silty clay loam; common, medium and fine strong brown (7.5YR 5/6) mottles; moderate, medium angular and subangular blocky structure; very firm; common fine pores; clay films on peds; medium acid; gradual smooth boundary.

Light brownish gray (10YR 6/2) silty clay loam; few, medium and fine, strong brown (7.5YR 5/6) mottles; moderate medium subangular blocky structure; very firm; common fine pores; clay films on ped surfaces and in pores; medium acid.

53

54

H30

9'a

sa

70

tm

ID 50 ..- • I'Cl U V) 40 ~

33

.. ::!

SITE 3

Depth (meters) Horizon

0.00-0.17 AP

Bt 1

Bt2

Bt3

0.81-1.11 Bt4

1. 42-1. 72 BW

2.03-2.33

I ------- Cl I

~ 2.6~ I~

I I ~

~ "/!, -. 3.2~ :~

-~ C2 3.86~ :~

~~~ 2Btlb

4.47-4.77 :~2Bt2b

~--..... 4.77-~ : ~ ..

PARTICLE SIZE (microns)

Figure 13 Cl(ty-free particle size distributi·on (Coulter Counter and sieve) in a Memphis soil and underlying Paleosol on the Prairie Terrace in Lafayette Parish, Louisiana.

Formation

.,... o I/)

s::: sID

"0 o E

Ol s:::

'r-s::: I'Cl

oj..J

s::: o u I/) I/)

ID o

I'Cl 'r-so ID a..

"0 ID

Q) • ..-us-1'Cl;:' s-.o s-Q) Ol I-S:::

.,.... r-

IDCO e,.- e,.- V)

S-I'ClO 'r- oj..J Q) n::s c,-s.:.OI'Cl a.. u a..

Table 15. Particle size distribution in a Memphis soil and underlying paleosol on the Prairie Terrace in Lafayette Parish, Louisiana.

Depth I Size Class and Particle Diameter (mm)

Horizonr Total =! Sand Silt

Sand Silt I Very Sand (2.0- (0.05- Clay Coarse I Coarse I Med

(IDeters~ .0.05) 0.002) «0.002) :2.0-1.0)1 (1.0-0.5) (0.5-Fine Very fine

(0.25-0.1) (0 .1-0.05 )

-Pct. of "" 2 mm----------------------------~ 1 16.1 0.00-0.17 0.17-0.30

. 0.30-0.48 0.48-0.81 0.81-1.11 1.11-1.4,2 1.42-1.72 1

1. 72-2.03 2.03-2.33 2.33-2.641 2.64-2.94 1 2.94-3.25 I

3.25-3.55 : 3.55-3.86 : 3.86-4.16 4.16-4.4,7 4.47-4.77 4.77-5.20

AP Btl Bt2 Bt3 Bt4

Bw

C1

C2

2Bt1b 2Bt2b

5.2 83.8 4.6 73.7 1.9 710.5 1.8 n.LI

2.0 81. 2 2.1 78.6 2.4 80.1 2.9 81. 9 2.2 81.5 2.2 82.2 2.9 82.7 2.5 82.2 0.9 83.8 1.1 81. 9 2.7 76.0 6.3 64.8 7.6 58.6 7.5 58.1

11.10 0.6 21.6 0.3 27.6 0.1 25.8 0.0 16.8 0.0 19.3 0.0 17.5 0.0 15.2 0.0 16.3 0.1 15.6 0.0 14.,4 0.0 15.3 0.0 15.3 0.0 17.0 0.0 21.3 0.2 28.9 0.4 33.8 0.5 34.,4 0.4

1.2 1.2 0.1 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.1 0.3 0.3 0.3 0.4

0.7 0.1 7.4 a a a a a a a a a o a a a

16.0 37.1 40.2 40.6 37.4 33.3 28.2 37.4 37.4 28.5 32.9 93.1 74.4 28.1 10.3

7.7 7.7

Tex-tural class

si sil sic sil sil sil sil sil sil sil sil sil sil sil sil sic sic sic

U1 U1

56

Table 16. Profile distribution trends of Phyllosilicates in the clay-size fraction of a Memphis soil and underlying Paleosol on the Prairie Terrace in Lafayette Parish, Louisiana.


stratified Depth Soil Vermiculite and

(meters) Horizon Kaolinite Micaceous Smectite (Eedogenic) interlayered

0.00-0.17 Ap xxx xxx xxxxxx xxx xx xxx 0.17-0.30 Btl xxxxxx xxxxxx xxx xx xxx 0.30-0.48 Bt2 xxxxxx xxxxxx xxxx xx xx 0.48-0.81 Bt3 xxxxx xxxxx xxxxxxx x xx 0.81-1.11 Bt4 xxxxx xxxxxx xxxxxxxx tr xx 1.11-1.42 xxxxx xxxxxx xxxxxxxx tr x 1.42-1. 72 Bw xxxxx xxxxxx xxxxxxxx tr x 1. 72-2.03 xxxxx xxxxx xxxxxxxxx x 2.03-2.33 C1 xxxx xxxxx xxxxxxxxxx x 2.33-2.64 xxx xxxxxx xxxxxxxxxxx tr 2.64-2.94 xxx xxxxx xxxxxxxxxxxx tr 2.94-3.25 xxxx xxxxx xxxxxxxxxxx tr 3.25-3.55 xxx xxxxxx xxxxxxxxxxx tr 3.55-3.86 C2 xxx xxxxx xxxxxxxxxxxx tr 3.86-4.16 xxxx xxx xxxxxxxxxxxxx tr 4.16-4.47 xxxxxx xxx xxxxxxxxxxx tr 4.47-4.77 2Bt1b xxxxxxx xxx xxxxxxxxxx tr 4.77-5.20 2Bt2b xxxxxx xx xxxxxxxxxxxx tr

Depth Horizon pH In 1:1

9u~en8ion

H20 /:aC1 z n.NKC1

Tab'le 17. Selected chemical characteristics of a Memphis soil and underlying Paleosol on the Prairie Terrace in Lafayette Parish, Louisiana

Extractl able Cation exchange

acidity cap_ilcit.1.. Saturation Cahl!; , Ex:r. Exch.1ngeable I BaCI2- effec- Nfl.,- 'urn of I I I i(Exch<ln;:e- Organle',re;S Fr"" ;',

Ca Mg K Na Al H TEA tive OAe ations i Al liH !Bases il able) ceo" F~ (flr.,':11 I I [ ,

I 1.1 I I I I [ , I (meters). .•.. .;.. ----milliequivalents/100 grarn~ Ii., ~

o 00-0 17 AP • I [ " 5.1 4.6 4.2 1.7 0.5 0.1 0.10.4 0.4 7.2 3.1 2.8 9.5 I 13 8 24 3.4 I 0.51 40

0.17-0.30 Btl 4.8 4.3 3.9 2.7 1.1 0.1 D.l 2.00.1 7.2 6.1 2.8 11.2 33 2 36 2.4' '0.65, 15 0.30-0.48 Bt2 4.9 4.3 3.8 4.4 2.2 0.1 0.1 2.6 0.2 8.7 9.6 5.0 15.5 27 2 44 2.0 i i 0.74 I 31 0.48-0.81 Bt3 5.0 4.4 3.8 4.6 3.1 0.2 0.1 2.2 0.2 9.2 10.4 7.6 17.2 I 21 2 46 1.5 I '1.08, 69 0.81-1.11 Bt4 5.0 4.6 3.9 4.8 3.6 0.2 0.1 1.3 0.4 6.1 10.4 5.5 14.8 12 4 59 1.3 ,1.00 84 1.11-1.42 5.24.7 4.0 4.8 3.4 0.1 0.1 0.8 0.2 6.1 9.4 3.4 14.5 I' 8 2 58 1.4 [ [L09[ 116 1.42-1.72 BW 5.3 4.7 4.0 5.0 3.2 0.1 0.10.5 0.2 6.1 9.1 12.4 14.5 , 6 2 1 58 1.6! '1.12 219 1. 72-2.03 5.2 4.7 4.0 5.4 3.4 0.1 0.1 0.6 0.1 4.6 9.7 13.2 13.6 6 1 66 I 1.6 i : 1.04 I 276 2.03-2.33 Cl 5.5 5.0 4.3 6.2 3.6 0.2 0.1 0.2 0.2 4.6 10.5 12.7 13.7 2 2 66 1.7 i 1.18' 306 2.33-2.64 5.4 5.0 4.3 6.0 3.6 0.2 0.2 0.0 0.2 4.6 10.2 11.5 14.6 0 2 68 1. 7 1.06' 320 2.64-2.94 5.3 4.9 4.2 5.5 3.2 0.2 0.40.0 0.2 4.6 9.5 11.2 13.9 a 2 57 1.7! ,1.11 300 2.94-3.25 5.4 4.9 4.1 5.1 3.2 0.1 0.3 0.0 0.2 5.1 8.9 8.8 13.6 a 2 64 1.6 I 1.11 I 310 3.25-3.55 5.6 5.2 4.3 6.2 3.6 0.2 0.2 0.0 0.2 4.6 10.4 12.8 14.8 0 2 69 1.7 I i 1 .09' 288 3.55-3.86 C2 5.6 5.2 4.4 5.9 3.5 0.1 0.2 0.0 0.2 4.6 .10.0 12.2 14.4 0 2 68 1.7 i 0.99. 282 3.86-4~16 5.7 5.3 4.4 6.6 4.2 0.2 0.2 0.0 0.2 3.6 11.4 12.3 14.8 a 2 76 1.6 I iO.95 228 ~.16-4.47 2Bt1b 5.6 5.3 4.4 8.2 4.7 0.2 0.2 0.0 0.2 2.5 13.5 16.9 15.8 0 1 84 1.1 I ;0.88 112 4~47-4.77 2Bt2b 5.7 5.3 4.4 8.9 5.1 0.2 0.2 0.0 0.2 4.6 14.6 18.3 19.0 0 1 76 1.7 I ,0.91 69 4.77-5.20 5.6 I 5.6 4.4 8.3 4.8 0.2 0.2 0.0 0.2 0.5 13.7 17.0 14.0 I 0 1 96 1.7 " 0.89: 49 I I , •

, [

,

I [ I I I I I I I I I I i I I

[ I

I I I I iii !

Ln -....J

Table 18. Whole-soil composition of nine elements and Ti/Zr ratio in a Memphis soil and underlying paleosol on the Prairie Terrace in Lafayette Parish, Louisiana.

Depth I Element (meters) Horizol~ Ca I Hg I K J Al I Fe J Si p

-----L-----tpm----- --:= __ l~~ , --------------------%------~------r------i

0.00-0.17 AP 0.05 0.06 0.20 2.57 1. 32 26.87 537 2312 397 0.17-0.30 Bt2 0.04 0.07 0.04 3.38 1.72 23.44 368 2459 413 0.30-0.48 Bt2 0.07 0.10 0.04 3R98 2.36 22.00 449 2613 385 0.48-0.81 Bt3 0.19 0.17 0.07 4.31 2.50 22.63 579 2665 431 0.81-1.11 Bt4 0.15 0.37 0.08 4.59 2.53 24.27 678 2780 481 1..11-1. 42

I 0.24 0.13 0.08 3.86 2.31 23.36 692 2746 535

1..42-1. 72 Bw 0.26 0.25 0.08 4.24 2.47 25.31 825 2960 596 1.72-2.03 0.26 0.30 0.07 4.14 2.34 24.59 865 2767 529 2.03-2.33

I CI 0.24 0.22 0.11 3.74 2.23 22.87 834 j 2668 543

2.33-2.64 0.16 0.18 0.101 4.26 2.52 27.16 841 3132 496 2.64-2.94 0.17 0.12 0.09 3.68 2.20 23.79 685 2880 400 2.94-3.25 0.14 I 0.09 0.08 3.80 2.24 24.37 728 3161 415 3.25-3.55 0 .. 11 0.06 1.31 3.51 2.16 23.82 747 3090 667 3.55-3.86 C2 0.07 0.03 1.26 3.39 2.08 34.35 731 3145 679 3.86-4.16 0 .. 11 0.05 1.13 3.54 2.03 24.45 600 3248 713 4.16-4.47 2Bt1b 0 .. 07 0.04 0.85 3.42 2.15 22.77 533 3084 677 4.47-4.77 2Bt2b 0 .. 20 0.19 0.95 4.51 2.74 26.40 562 3293 746 4.77-5.20 0.34 0.35 1.12 5.50 2.80 29.74 434 3664 718

I I I : I I

I I

I I \

I \

I

\ I

Ratio [ri/Zr

5.82 5.95 6.79 6.18 5.78 5.13 4.97 5.23 4.91 6.31 7.20 7.62 4.6 4.6 4.6 4.6 4.4 5.1

VI (Xl

59 SITE 4

This stop is located within a few meters of the site represented by the accompanying morphological description and supporting data. It is on the Mississippi River Alluvial Plain near the southern edge of a salt dome (Anse La Butte) which forms a local topographic high lying north and east of the site. Locally, elevations range from a little less than 3 to about 7.5 meters. Directly west of the site, highest elevations on the Prairie Terrace are in excess of 14 meters. The area is drained by Bayou Vermilion immediately west of the site. Bayou Teche occupies a former Mississippi River Channel approximately 5 km to the east.

The Mississippi River, now flowing approximately 80 krn to the east, near Baton Rouge, abandoned the Teche-Mississippi Channel about ~OO BP (Kupfer, 1964). The Red River flowed in the Teche-Mississippi Channel for at least several hundred years following its abandonment by the Mississippi and partially filled the existing channel with sediment (Saucier, 1974; Frazier, 1967; Howe and Moresi, 1933). The reddish color of these sediments, restricted almost totally to the former Mississippi Channel, are a striking contrast to the surrounding Mississippi River alluvium.

Important relationships between the loess and overlying and. underlying deposits are shown in Figure 14. Daniels and Young (1968). studied the loess on the adjacent Prairie Terrace and indicated that it mantled the escarpment to the Mississippi River Alluvial Plain. They recognized the occurence of buried loess deposits on the alluvial plain and that soils developed in loess occupied areas not covered with alluvium. Subsequent investigations by the authors indicate that the loess buries a surface presumed to be a late-Prairie component of the Prairie Terrace or a Post-Prairie Terrace. The loess continues to thicken eastward in the areas investigated. Although its easternmost extent has not been determined~ it is presumed to be west of the former Mississippi River Channel now occupied by Bayou Teche. The alluvium overlying the loess becomes generally thinner to the north of the site and relatively large areas are at the surface in northern Lafayette and southern St. Landry Parishes, for example. To the south, the alluvium thickness and the southern extent of the buried loess has not been determined. Areas of loess exposed at the surface and surrounded by the IIlore recent alluvium represent high areas. such as Anse La Butte, on the former surface. The frequency of occurence of such areas decreases southward until they become absent entirely.

Soils developed in the Mississippi River alluvium in the area are mostly Iberia (Vertic HaplQquall) and Baldwin (Vertic Ochraqualf) with small amounts of Dundee (Aerie Ochraqualf) on the highest positions of the Bayou Teche natural levees. These soils have developed in sediments deposited in conjunction with a Mississippi River belt formed approximately 3,800 to 2,800 years ,BP (Kupfer, 1964). Soils developed in loess in areas where it has not been covered by more recent alluvium are predominantly Acy (Aeric Ochraqualf), Coteau (Glossaquic Hapludalf), Frost (Typic Glossaqualf), Jeanerette (Typic Argiaquoll) and Patoutville (Aerie Ochraqualf)~ These soils are mrirphologically indistinguishable from soils in the same series developed in the loess deposits on the higher Prairie Terrace to the west. The limited existing data suggest that soils on the lower position may have less total clay, higher base status and greater smectite content in the clay-size fraction compared to those on the higher terrace. The absence, in this position, of soils developed in the thick loess deposits having well drained sola, such as the Memphis, is considered a result of the longer periods of saturation at shallower depths compared to soils developed in similar deposits on the higher Prairie Terrace.

Figure lQ, Alluvium - loess - terrace fo~ation relationships in the vicinity of LafayetteJ Louisiana,

.. ~ Holocene Mississippi River alluvium [illlioess [Ell Prairie (?) or Post-Prairie (?) Terrace ~ Prairie Terrace

.. Observation point

it

4

12

10

~ Q)

8(i) ~ c:

~~~6§

J@iiillllil!W;.I'%:~ll%l.t"t : ~ Vermi 11 ion Bayou

4 Distance in Kilometers·

o -1

0\ o

II

SITE 4-

Mississippi River Alluvial Plain (backswamp)

Inclusion (fine-silty, mixed, thermic Vertic Ochraqualf?) in Baldwin soil (fine, montmorillinitic, thermic Vertic Ochraqualf) area.

Location: Lafayette Parish, La. approximately 70 meters N of Lafayette-St. Martin Parish line in SW corner of that part of survey section 60 that lie's within Lafayette Parish (elevation: approximately 4.5 meters),

The Baldwin series is comprised of poorly drained, slm-1ly permeable soils developed in recent, clayey Mississippi River alluvium that is more than about one meter thick.

Formation

bD P

"Fi P

".-1 (1j .w p 0.-1 (j 0

[f] [f] 0 [f] Q) Q).-I o (1j

.-Ip.,

(1j'"'(j ".-1 Q) H ".-1 o H Q) ;::! p.,..o

Soil Horizon

Ap

Btl

2Btlb

2Bt2b

Depth (meters)

0.00-0.27

0.27-0.58

0.58-1. 27

1.27-1.60

Morphology

Very dark grayish brown (10YR 3/2) silty clay; strong, medium, fine and very fine blocky and subangular blocky structure; extremely firm, many fine roots; neutral; clear smooth boundary.

Mottled grayish borwn (lOYR 5/2) and yellowish brown (lOYR 5/4-5/6) silty clay loam; exteriors of most peds are very dark grayish bro,"1ll (lOYR 3/2); Clay films and/or pressure faces on many ped surfaces; strong, medium angular and subangular blocky structure; very firm; common fine roots, few. medium black concretions. neutral gradual smooth boundary.

Mottled grayish brown (lOYR 5/2) and yellowish brown (lOYR 5/4-5/6) silty clay loam; dark grayish brown (lOYR 4/2) clay films; moderate, medium, subangular blocky ,structure. firm; few fine roots; common, medium. black concretions; neutral; diffuse smooth boundary.

Mottled, light brownish gray (lOYR 6/2) and brownish yellow (lOYR 6/6-6/8) silt loam; weak to moderate, subangular blocky structure, firm; clay films on ped faces and lining pores are mostly dark grayish brown (lOYR 4/2) or grayish brown (lOYR 5/2); few, fine, black concretions; slightly acid; diffuse irregular boundary.

61

62

2Bt3b

2C1b

2C2b

2C3b

3bwb

1.60-2.51

2.51-3.45

3.45-4.36

4.36-4.97

4.97-5.23

Mottled, grayish brown (10YR 5/2) and yellowish brown (lOYR 5/4-5/8) silt loam; weak, coarse sub angular blocky structure; friable; dark grayish brown clay films on some ped faces and in pores; common, fine black concretions; neutral in upper part becoming moderately alkaline in lower part.

Yellowish brown (10YR 5/6) to brownish yellow (10YR 6/6) silt loam; many, medium, light brownish gray (10YR 6/2) mottles; massive; friable; few, fine, black concretions; neutral in upper part; mildly alkaline in lower part; diffuse. smooth boundary.

Yellowish brown (10YR 5/4) silt loam; massive; friable; moderately alkaline; gradual smooth boundary.

Brown (10YR 5/3) silt loam; common, fine. light brownish gray (10YR 6/2) and yellowish brown (10YR 5/4) mottles; massive; friable; mildly alkaline; clear smooth boundary.

Strong brown (7.5YR 5/6) silty clay; few, fine and medium reddish brown (5YR 4/4-5/4) and yellowish brown (10YR 5/6) mottles; strong. medium, angular and subangular blocky structure. neutral.

1~~

Ba

8\:1

70

6a

I.tJ ~B .-

ttl U

V')

49 ~

ala

20

11:1

\:l

Depth (meters)

SITE 4

Horizon

......... ------AP

----... __ - Bt 1

'--_______ 2Bt 1 b

___________ 2B t2b

. ~ ~ '-------2Bt3b

1.90-2.;~ ~ ~ ~ ~ ~-

-------2Clb

-:------

____ - ___ 2C2b

3.75-4.06 ~

/:~ --~~ j ................ _------

4.36-4.67 '-------

I

~.23r_ I A .........." ~~Bwb

PARTICLE SJZE (microns)

63

Formation

E ~

Vl > .Vl =:l C .,....

C C oL Vl

It; C .j..J .,.... C C $., It sill <1J.j..J <1J U > c v ill ..... C C

0::: 0::: U E

I

~

o Vl o ill r-<tl

0..

..... s=:l .0 .

en C ..... C 'r-rtI

.j..J I:: o U

V)

U1 ill o

<U 'r-so I.tJ n.

I ~ I <1J .....

U s<U =:l s-.o s-ill en 1-1:: ..... ,.....

-I.;::.;:: ;;; s-<uo

..... .j..J ill mCrs- 0 m

0.. un.

Figure 15 Clay-free particle size distribution (Coulter Counter and sieve) in a Baldwin soil unit inclusion on the Holocene ~lississippi River all'uvial plain in Lafayette Parish, Louisiana.'

o.

Table 19. Particle size distribution in a Baldwin soil unit inclusion and underlying paleosols on the Holocene Mississippi River alluvial plain in Lafayette Parish, Louisiana.

Size Class and Particle Diameter (rom) - Total Sand Depth Horizon , Silt Sand Silt Very Sand

(2.0- (0.05- Clay Coarse Coarse Medium Fine Very fine (meters' 0.05) 0.002) «0.002) 2.0-1.0) (1.0-0.5) (0,5-0.25) (0.25-0.1) (0.1-0.05)

,!

Pct. of"'- 2 wur

AP I

1.9 57.2 40.9 0.1 0.2 0.2 0.3

Cf\ .p..

Tex-tural class

1 I I I I 1 1 1.2 30.1 sic 1:1 ... 1 I 1 I. t:.c: -, ')') n A , A , ~ " - -O.~, ...., ....... I VJo/ J ..... ;7 V...L v • .L U.l. U • .L 1.3 46.9 s~cl

0.58-0.96 2Btlbl 2.4 68.7 28.9 0.3 0.4 0.2 0.1 1.3 28.6 slcl I

0.96-1.27 : 2.5 70.6 26.9 0.4 0.4 0.2 0.2 1.3 28.2 sicl 1 1"\-,> ..... "P'Io ..... , !

1. 1 2. 2. 2. 3. 3. 3. 4. 4 4 4.

Table 20. Profile distribution trends of Phyllosilicates in the clay-size fraction of a Baldwin soil unit inclusion and underlying paleosol on the Holocene Mississippi River Alluvial Plain in Lafayette Parish, Louisiana.

Mineral Com:eonent Inter-

stratified Depth Soil and

(meters) Horizon Kaolinite Micaceous Smectite Interlayered

0.00-0.27 Ap xxxx xxxx xxxxxxxxxxxx tr 0.27-0.58 Btl xxxx xxxx xxxxxxxxxxxx tr 0.58-0.96 2Bt1b xxxx xxxxx xxxxxxxxxxx tr 0.96-1. 27 xxxx xxxxxx xxxxxxxxxx tr 1. 27 -1. 60 2Bt2b xxx xxxxxx xxxxxxxxxxx tr 1.60-1.90 2Bt3b xxx xxxxxx xxxxxxxxxxx tr 1. 90-2 .20 xxx xxxxxxx xxxxxxxxxx tr 2.20-2.51 xxx xxxxxx xxxxxxxxxxx tr 2.51-2.84 2C1b xxx xxx xxx xxxxxxxxxxx tr 2.84-3.14 xxx xxxxxx xxxxxxxxxxx tr 3.14-3.45 xxx xxxxxx xxxxxxxxxxx tr 3.45-3.75 2C2b xxx xxxxxx xxxxxxxxxxx tr 3.75-4.06 xxxx xxxxx xxxxxxxxxxx tr 4.06-4.36 2C3b xxxx xxxxx xxxxxxxxxxx tr 4.36-4.67 xxxxxx xxxxx xxxxxxxxx tr 4.67-4.97 xxxxxxxx xxx xxx xxxxxx tr 4.97-5.23 3Bwb xxxxxxx xxxxx xxxxxxxx tr

65

Depth

(meters) O.OO-O.ll 0.27-0.58 0.58-0.96 0.96-1. 27 1.27-1.60 1.60-190 1. 90-2.20 2.20-2.51 2.51-2.84 2.84-3.14 3.14-3.45 3.45-3.75 3.75-4.06 4.06-4.36 4.36-4.67 4.67-4.97 '4.97-5.23

Horizon

~IP .Btl 2Bt1b

2Bt2b 2Bt3b

2Clb

2C2b

2C3b

3Bb

pH In 1:1

suspension H20 "faC12 n.NKCl

7.0 6.7 6.0 6.8 6.5 5.5 6.8 6.5 5.5 6.7 6.4 5.4 6.5 q.1 5.1 6.7 .6.3 5.3 7.6 . 7.3 6.9 7.9 7.6 7.1 7.7 7.5 7.0 6.7 6.4 5.4 7.6 7.4 6.8 7.8 7.6 7.1 7.8 7.5 7.1 7.8 7.4 7.0 7.8 7.4 7.0 7.4 7.1 6.3 7.2 7.0 6.1

0\ 0\

Table 21~ Selected chemical characteristics of a Baldwin soil unit inclusion and underlyin9 Paleosols c'n the Holocene Mississippi River Alluvial Plain in Lafayette Parish, Louisiana

Exchangeable Ca Mg I KINa Al

I

H

Extract able

acidity ~~~~~~ ____ ~ BaClz- purn of TEA tive cations

--.-:.-----rnrn illi e q u iva 1 en t s /100 g ram 9-----:" .

4.20.3 0.1 0.0 0.2 5.1 23.9 29.1\ 28.8 19.1 15.5 10.6 11.2 9.1 7.6 I

10.1 10.4 10.4 11.0 14.3 15.4 15.6 14.4 14.3 10.3 16.0

4.9 0.2 0.1 0.0 0.2 4.1 20.9 22.8 25.8 4,0 0.1 0.1 0.0 0.2 3.6 15.0 17.0 18.4 4.3 0.2 0.1 0.0 0.2 3.1 15.9 16.6 18.8 4.0 0.2 0.1 0.0 0.2 3.1 13.6 16.4 16.5 3.9 0.2 0.2 0.0 0.2 2.5 12.1 14.5 14.4 3.9 0.2 0.1 0.0 0.2 0.5 14.5 12.2 14.8 6.8 0.2 0.1 0.0 0.2 0.5 17.6 13.0 17.9 4.9 0.3 0.1 0.0 0.2 0.5 15.9 13.6 16.2 5.4 0.2 0.1 0.0, 0.2 1.5 16.9 11.9 18.2 4.2 0.2 0;1 0.0 0.2 0.5 19.0 12.2 19.3 3.6 0.2 0.1 0.0 0.2 I 1.0 19.5 12.2 20.3 3.6 0.2 0.1 0.0 0.2.1 1.0 19.7 11.1 20.5 3.9 0.2 0.1 0.0 0.2 0.5 18.8 11.1 18.8 4.0 0.2 0.1 0.0 0.2 0.5 18.8 11.5 19.1 4.8 0.2 0.1 0.0 0.2 1.0 15.6 13.4 16.4 7.2 0.3 0.1 0.0 0.2 2.1 23.8 21.4 25.7

Al

.1 ,

Saturation \ Cah\g: : : E,,~r. 1 !(Exchange-!organic 'fre~S 'free ;'- .

H liBaseS!able) C .CO) IF":' (I1r"'.'11 ,I -- ~

7. :;; ___ ;':'-

4.5 , 0.50 30 o 1 80 3.2 ' 0.34 40 o 1 80 2.6 : 0.94; o 1 83 2.6 ;0.50, 74 o 1 81 2.3 ,0.96 244 o 2 83 1.9 . 0.98 280 o 1 97 2.6 ,0.84' 277 o 1 97 1.5 'o.n' .121 o 1 97 2.1 : 0.71 212 o 1 92 2.0 0.78' 340 o 1 97 3.4 '0.78' 305 o 1 95 4.3 0.69 202 o 1 95 4.3 0.64, 148 o 1 97 3.7 '0.75 260 o 1 97 .3.6 0.79' 182 o 1 94 2.1 0.5237 o 1 92 2.2 0.56 30

Table 22. iNhole-soil composltlon of nine elements and Ti/Zr ratio in a Baldwin soil unit inclusion and underlying Paleosols on the Holocene Mississippi River Alluvial Plain in Lafayette Parish, Louisiana.

Depth (welers)

0.00-0.27 0.27-0.58 0.58-0.96 0.96-1. 27 1.27-1.60 1. 60-1. 90 1. 90-2.20 2.20-2.51 2.51-2.84 2.84-3.14 3.14-3.45 3.45-3.75 3.75-4.06 4.06-4.36 4.36-4.67 4.67-4.97 4~97-5.23

r-

HorizClil

AP Btl Bt2b

Bt2b Bt3b

2c2b , ,

2c2b

I

2c3b

3Bwb

Element Ratio

--:~ __ ! ___ ~: __ l ___ ~ __ ~ __ ~: __ L_~~ __ l __ == __ 1 -~-J-----L----JDm----J-_== __ L~~ Ii/ Z r 0.10 0.14 I 1.35 4.76 2.82 ' 25.95 837

14990 8051 6.19

0.02 0.03 1.36 4.28 2.08 26.58 571 4251 682 6 ;23 0.03 0.02 1.44 4.57 2.85 27.66 494 4410 650 6.78 0.26 0.31 1.55 5.30 2.69 28.38 805 4033 554 7.27 0.03 0.05 1.35 3.46 2.42

I

5.46 22.68 '1123 3604 659 0.08 0.02 1.44 3.91 2.62 25.42 1074 3500 497 7.04 0.32 0.15 1.44 3.50 2.22 25.40 1014 3511 ·479 I 7.32 0.24 I 0.07 1.08 1.07 1.60 19.77 813 2785 416 6.69 0.10 0.05 1.22 2.31 2.01 23.34 910 3191 486 6.56· 0.07 0.04 1.52 4.07 2.57 27.47 11022

1

3713 487 7.62 0.15 0.04 1. 34 3.15 2.21 24.68 888 2843 386 7.36 0.32 0.04 1.37 2.78 2.26 25.53 938 ,

1

3122 441 7.07 I 0.52 0.07 1.37 2.69 2.14 25.25 890 I 3045 453 6.72 I 0.05 0.10 1. 22 2.56 1.86 22.16 890 i

12773 437 6.25

0.06 0.03 1. 37 3~54 2.17 25.48 778 i 3186 469 6.79

0.12 0.03 1.30 4.17 2.20 26.66 660

I ! 3258 498 I 6.54

0.25 0.05 1.62 6.57 3.69 29.30 745 ! 4243 . 529 I 8~02

I I I I l

i I i

i 1 r ,.

1 ~ '--l

68 S!TE 5

This stop is within a few meters of the site represented by the accompanying morphological description and supporting data. A site where Touchet and Daniels (1970) described 3.35 meters of pre-Prairie post-Montgomery loess is about 6.5 Km south southwest of this location near Turkey Creek, Louisiana.

The site is on the Intermediate Terraces (Snead and Mc Culloh, 1984). Our designation as Montgomery is for convenience and consistence with our data files and previous use (1982). It also coincides with the Terraces most common identification since Fisk's 1938 and 1940 works. Other selected identifying names used in the past are given in the discussion for Site 2.

Southwestern Louisiana is the principal area of occurrence of the Terrace. Saucier (1974) indicates that it represents ' •.• remnants of the alluvial valley fill and coastal plain that deve)oped during the Yarmouth Interglacial Stage ... I. Other workers have indicated that it was deposited during the'Sangamon Interglacial Stage (see discussion Site 2).

The gently sloping areas of the loess-covered Montgomery Terrace are about 12 meters above the nearly level Prairie Terrace to the south and 25 to 30 meters above the wide alluvial plain to the east. The escarpment to the alluvial plain is steep and highly dissected. The escarpment to the Prairie Terrace is gently sloping with little dissection. Elevations of the loess-covered part of the Terrace range from 43 meters near the valley wall in the northeastern part to about 20 meters in the southwestern part.

Maximum thickness of the loess has not been determined but exceeds 9 meters in areas near its southeastern I imits of occurrence at the surface. Thickness and distrubution patterns of the Peoria loess (Figures 2 - 4) indicate that a small increment may have been deposited on the pre-Peoria loess in areas near its eastern edge.

A number of modern soils developed in the pre-Peoria loess are identified In Louisiana (see Tables 4 and 5) G Differences in many characteristics between them and soils developed in Peoria loess are compared qualitatively in Table 6. In the West Central Louisiana area soils developed in the pre-Peoria loess are Calhoun (Typic Glossaqualf), Dossman (Ultic Hapludalf). Duralde (Fragic Glossudalf) •

. Evangel ine (Haplic Glossudalf), and Tenot (Aeric Albaqualf). Bartelli (1973) has discussed genetic processes in soils developed in loesses in the area and considers Ferrolysis to be a major process in formation of soi Is such as the Duralde which he considers developed from a former Fragiudalf. A number of soils developed in pre-Peoria loess in the area form a possible chronosequence with soils developed in Peoria loess where both have analogous landscape positions and drainage characteristics. Examples include Memphis - Dossman, Duralde - Grenada, Calhoun -Calhoun (taxadjunct).

SITE 5

Montgomery Terrace

Duralde Soil taxadjunct (fine-silty, siliceous, thermic Fragic Glossudalf?)

Location: Evangeline Parish,Louisiana. NE~, SE~, sec. 29, T.1S, R1E. (elevation: approximately 3S.5 meters).

The Duralde series is comprised of somewhat poorly drained, slowly permeable soils formed in areas where a pre-Peoria-Post-Montgomery loess mantle more than about one and one-half meters thick has not been covered by more recent deposits.

Formation

M 'M a (JJ

Soil Horizon

A

Bw

B/E

Btl

Depth (meters)

O.OO-O.OS

0.OS-0.23

0.23-0.38

0.3S-0.69

Morphology

Dark grayish brown (10YR 4/2) silt; few. fine, faint gray (10YR 6/1) mottles; weak, fine, granular structure; friable; many fine and medium roots; common, medium and fine brown concretions; very strongly acid; clear wavy boundary.

Pale brown (10YR 6/3) silt; common, medium, faint light gray (10YR 7/2) mottles, few, medium. faint brown (7.5YR 5/4) mottles; weak, medium, subangular blocky structure; friable, few fine and medium roots; very thin silt coatings lining some pores and on some ped faces; thin discontinuous clay films lining some pores. Many, fine brown to black concretions; very strongly acid; clear irregular boundary.

Estimated 60 percent is like underlying horizon and remaining 40 percent like overlying horizon except light gray (lOYR 7/2); very strongly acid; clear wavy boundary.

Grayish brown (10YR 5/2) to brown (10YR 5/3) silt loam; common, medium, distinct yellowish brown (lOYR 5/6) to red (2.5 YR 4/6) mottles; moderate, medium and fine, sub angular blocky structure; firm; common fine pores; continuous clay films on peds; few medium and fine brown to black concretions; very strongly acid; clear smooth boundary.

69

70

Bt2 '

Bt3 1.73-2.46

Bw 2.46-2.97

Cl 2.97-4.11

C2 4.11-4.57

Pale brown (lOYR 6/3) silt loam; common, medium, faint. light gray (lOYR 6/2) and few medium faint, yellowish brown (lOYR 5/4) mottles; moderate, medium, subangu1ar blocky structure; firm; many fine pores; thin continuous clay films on many ped surfaces; thin coatings of silt on some ped surfaces; common, medium and fine brown to black concretions; very strongly acid in upper part becoming less acid with depth; neutral in lower part; gradual wavy boundary.

Brown (7.5YR 4/4) silt loam; common, medium and fine light gray (lOYR 7/2) mottles; moderate to weak, medium subangu1ar blocky structure; firm; thin, nec1r1y continuous clay films on most ped surfaces; clay films in pores; thin gray silt coatings on many vertical ped faces; common, medium and fine, brown to black concretions; neutral; gradual wavy boundary.

Brown (7.5YR 5/4) silt loam; few, fine, light gray (lOYR 7/2) and few, fine, faint strong brown (7.5YR 5/6) mottles. Weak, medium sub angular blocky structure; friable; thin clay films on some ped surfaces and lining some pores; thin gray silt coatings on some peds; common, medium and fine, black to brown concretions; boundary.

ntlll1t'r!l1 III ... .L __ ............. ~, gradual wavy

Strong brown (7.5YR 5/6) silt loam; weak, medium sub angular blocky structure; friable; clay films on some ped faces and in pores; black stains common on many ped faces; few fine black concretions; gray silt coatings on many vertical ped 'faces; neutral; gradual smooth boundary.

Light yellowish brown (lOYR 6/4) silt loam; few, fine and medium, faint light gray (lOYR 7/2-7/3) mottles; few, fine, faint strong brown (7.5YR 5/6) mottles; thin discontinuous clay films on some ped faces and in pores; gray coatings and gray seams along some vertical ped faces. Common, fine black concretions; neutral; gradual smooth boundary.

bO ~

'M ~

'M cO .j...J

~ o (j

aJ (j

cO H.-l H 0 aJ (fJ

H 0 aJ

:>-'.-l H cO aJ Ii< S 0"0 bOaJ

.j...J 'M ~ H o ::1 ~,o

2Btb 4.57-5.21 Yellowish brown (10YR 5/4) silty clay loam; common, medium and coarse distinct light gray (10YR 7/2) mottles and few to common, fine and medium, prominant red (2.5YR 4/6) mottles; moderate, medium, subangular blocky structure; firm; clay films on ped surfaces and in pores; few fine brown to black concretions; neutral.

71

SITE 5 72

Depth (meters) Horizon Formation

(1) ..-rt3 U

Vi

0.00- A

BW

B/E Btl

0.53-0.69

Bt2 0.94-1. 19

1. 45-1. 73 - ___ Bt3

79

BB -------BW - I

~ I

~B '" 7" 2 9"7 -~-c. •• ~' ~

3\l - I

211

111

I _____ Cl

: 2 tl ?7-4 tl? -~....... _/\ '.~/~ ; ~ '----

I

4.57-4.72 ~ ~ ~; " '--28tb

- . PARTICLE SIZE (microns)

Figure IS. (lay-free particle size distribution (Coulter Counter and sieve) in a Duralde soil taxadjunct and underlying Paleosol on the Montgomery Terrace in Evangeline Parish, Louisiana.

.r-o III

c s(1) -0 o E

01 e

.r-e

.r-rt3 +I C o U

III In

-(1)

I C .,.... ttl +I e

o

ttl .r-so (1) a..

I QJ s

a..

>,0"0 S-U(1) W dr= r= E(1)S-O OU:::I1Il 01tt1-00 +IS- (1) C s- 01..o(1)Crt3 ::E I- ..... a..

o. O. O. O. O. O. O. 1. 1. 1. 1. 2. 2. 2. 2. 2. 3. 3. 3. 4. 4. 4. 4. 4. 4.

Table 23. Particle size distribution in a Dura1de soil taxadjunct and underlying paleosol on the Montgomery Terrace in Evangeline Parish. Louisia.na.

L ----1- Size Class and Particle Diameter (mm) Total Sand -

I , Silt Sand Silt Very I Sand Tex-,

(2.0- (0.05- Clay Coarse Coarse Medium Fine Very fine I

tura1 (meters 0.05) 0.002) «0.002) :2.0-1. 0) 0,0-0.5) (0.5-0.25) (0.25-0.1) (0.1-0.05 ) class

, -Pet. of "- 2 mur

00-0.08 A 7.7 83.4 8.9 1.0 1.2 1.2 1.2 3.2 10.8 S1 08-0.23 Bw 5.6 83.1 11.3 2.0 1.0 0.3 0.6 1.7 14.8 si 23-0.38 B/E 4.7 77 .1 18.2 1.0 0.8 0.5 0.5 1.9 16.4 sil 38-0.53 Btl 2.7 71.4 25.9 0.3 0.3 0.2 0.4 1.5 26.4 si 1 53-0.69 2.9 73.9 23.2 0.4 0.3 0.3 0.4 1.5

I 25.5 sil

69-0.94 Bt2 3.6 75.0 21.4 1.1 0.5 0.2 0.3 1.5 20.8 s i 1 94-1.19 2.4 78.5 19.1 0.2 0.2 0.1 0.3 1.5

I 32.7 sil

19-1.45 2.6 80.2 17.2 0.1 0.2 0.2 0.4 1.7 30.8 sil 45-1. 73 Bt3 2.0 77 .4 20.6 0.1 0.1 0.1 0.2 1.5 I 38.7 sil 73-1. 90 2.1 76.5 21.4 0.2 0.2 0.1 0.2 1.4

I 36. Lf s i 1

90-2.06 . 2.2 80.8 17.0 0.1 0.1 0.1 0.3 1.7 36.7 sil :)6-2.21: I

54.2 sil 1.5 81.3 17.2 0.1 0.1 0.1 0.1 1.3

:

21-2.46 ' Bw 2.1 77 .6 20.3 0.1 0.1 0.1 0.1 1.9 37.0 sil !j.6-2.72 ; 2.7 76.1 21.2 0.1 0.1 0.1 0.1 2.2 28.2 sil 72-2.97 : 2.8 76.5 20.7 0.1 0.1 0.1 0.1 2.5 I 27.3 sil 97-3.23 C1 3.0 76.8 20.2 0.1 0.1 0.1 0.2 2.7 I 25.6 sil 23-3.53 4.0 77 .1

I 18.9 0.1 0.1 0.2 0.2 3.5 I 19.3 5il

53-3.81 6.3 76.4 17.3 0.1 0.1 0.1 0.4 5.8 12.1 sil 31-4.11 10.0 71. 7 I 18.3 0.1 0.1 0.1 0.4 9.2 7.2 s1l Ll-4.27 C2 11.6 66.4 22.0 0.1 0.1 0.1 0.4 11.1 5.7 sil 27-4.42 10.8 65.6 23.6 0.1 0.1 0.1 0.3 10.3 I 6.1 s11 +2-4.57 9.5 64.4 26.1 0.1 0.1 0.1 0.2 9.1 i 6.8 sil 57-4.72 2Btb 9.0 61.1 29.9 - 0.1 0.1 0.1 0.2 8.7 6.8 sic 72-4.98 8.9 56.8 34.3 0.1 0.1 0.1 0.2 8.6 6.4 sic :18-5.21 11.2 55.0 33.8 0.1 0.1 0.1 0.2 11.0 4.9 sic

I i

I '-J W

Table 24. Profile distribution trends of Phyllosilicates in the clay-size fraction of a Duralde soil taxadjunct and underlying paleosol on the Hontgomery Terrace in Evangeline Parish, Louisiana.

Mineral ComEonent Interstratified

Depth Soil Chlorotized and (meters) Horizon Kaolinite Micaceous Smectite Vermiculite interlayered

0.00-0.08 A xxxxxxxxxx tr x xxxxx xxxxx ·0.08-0.23 Bw xxxxxxxxxx tr xx xxx xxxxx 0.23-0.38 B/E xxxxxxxxXx tr xxxx: xx xxxx 0.38-0.S3 Btl XXXXXXXXx x xxxxxx x xxx 0.S3-0.69 XXXXXXXx XX xxxxxx x xxx 0.69-0.94 Bt2 xxxxxxxx XX xxxxxxx. tr xx 0.94-1.19 xxxxxxxx XX xxxxxxxx xx 1.19-1.45 }:xxxxxxx XX xxxxxxxx~ xx 1.45-1.73 Bt3 XXXXlOCX xxx xxxxxxxx. xx 1. 73-1. 90 XXXXlOCX xxxx xxxxxxxxx xx 1. 90-2.06 xxxx xxxx. xxxxxxxxxx xx 2.06-2.21 xxxx xxxxx xxxxxxxxxx xx 2.21-2.46 Bw xxxx xxxxx xxxxxxxxxx xx 2.46-2.72 xxxx xxxxx xxxxxxxxxxx x 2.72-2.97 xxxx: xxxx xxxxxxxxxxxx x 2.97-3.23 C1 xxxx: xxx xxxxxxxxxxxx x 3.23-3!S3 xxxx xxx xxxxxxxxxxx x 3.81-4.11 xxxxxx x xxxxxxxxxx xx 4.11-4.27 C2 XXXXX:KX tr xxxxxxxxxx xxx 4.27-4.42 xxxxxxxx tr xxxxxxxx xxxx 4.42-4.S7 xxxxxxxxx tr xxxxxxx xxxx 4.S7-4.72 2Btb xxxxxxxxxxx tr xxxxx xxxx 4.72-4.98 xxxxxxxxxxx tr xxxxx xxxx 4.98-S.21 xxxxxxxxxxx tr xxxxx xxxx

'-l ~

Depth

(meters}

0.00-0.08 0.08-0.23 0.23-0.38 0.38-0.53 0.53-0.69 0.69-0.94 0.94-1.19 1.19-1. 45 1.45-1. 73 11.73-1. 90 1. 90-2.06 2.06-2.21 2.21-2.46 2.46-2.72 2.72-2.97 2.97-3.23 3.23-3.53 3.53-3.81 3!.81-4.1l 4.11-4.27 4'.27-4.42 4.42-4:57 4l57-4.72 4.72-4.98 4,98-5.21

Horizon

A Bw 8,1 Btl

Bt2

Bt3

Bw

C1

C2

2Btb

pH In 1:1

Table 25. Selected chemical characteristics of a Dura1de soil taxadjunct and underlying Paleosol on the Montgomery Terrace in Evangeline Parish, Louisiana.

Extrllct I ! able Cation exchange I :

acidity capacity : Saturation : Cah!b 9uspension Exchangeable BlIC1 2- cffee- 1'11.- "urn of I I I(Exch~nge- :Oq::a:;1c 'F!"P;S ,rrp,",

H2 0 faCl! ~NKCl Ca J Mg I K Na Al H TEA tive OAe ations I Al H ~ases i able) C CO J r"

5.0 4.3 3.6 4.8 4.2 3.4 4.8 4.1 3.3 4.8 4.2 3.2 4.9 4.3 3.4 5.0 4.5 3.4 5.4 5.0 3.8 6.1 5.7 4.7 6.7 6.1 5.2 6.7 6.4 5.4 7.0 6.5 5.4 7.2 6.5 5.6 7.2 6.7 5.7 7.1 6.2 5.6 7.1 6.4 5.7 7.2 6.6 5.7 7.2 6.6 5.7 7.1 6.6 5.6 7.2 6.5 5.8 7.1 6.6 5.8 7.0 6.6 5.8 6.9 6.5 5.7 6.9 6.6 5.8 7.0 6.6 5.7 6.8 6.5 5,.7

0.6 0.8 1.6 ,3.1 3.8 4.6 4.6 5.4 6.2 7.0 5.9 5.0 6.8 6.2 6.6 6.4 6.1 5.6 4.4 5.7 4.8 6.0 6.6 7.8 6.5

J 1.1 I ' mHliequiva1ents/100 gram9--- ,7.! ;:: __ _

1.0 1.4 2.2 3.6 3.8 4.4 4.0 4.2 5.0 5.3 4.4 3.8 5.4 4.8 5.1 4.7 4.4 4.3 3.6 4.7 4.0 5.0 5.6 6.6 5.6

I ' j 0.1 0.1 2.2 0.3 6.7 4.1 7.8 8.3 54 7 19, 0.6 0.10.13.30.3 5.1 5.9 6.8 7.4 56 5 31 i 0.6 0.10.25.40.1 9.2 9.6 10.4 13.3 56 1 31 I 0.7 0.1 0.4 6.4 0.0 9.7 13.6 13.1 16.9 47 0 43 i 0.9 0.1 0.6 4.4 0.2 8.2 12.9 12.8 16.5 34 2 50 I 1.0 0.1 0.8 2.2 0.4 6.6 12.5 10.8 16.5, 18 3 60 I 1.0 0.1 0.8 0.3 0.3 3.2 10.0 8.3 12.6 3 3 75 I 1.2 0.1 0.8 0.1 0.1 1.0 10.7 8.1 11.5 1 1 91 1.3 0.1 1.1 0.0 0.1 0.5 12.5 9.8 12.9 O· 1 96 1.2 0.1 1.2 0.0 0.1 1.5 13.7 14.0 14.1 0 1 89 1.3 0.1 1.1 0.0 0.2 2.5 11.7 10.0 14.0 0 2 78 1.3 0.1 1.0 0.0 0.2 0.5 10.1 10.2 10.4 0 2 95 1.3 0.1 1.5 0.0 0.1 1.0 13.9 13.0 14.8 0 1 93 1.3 0.1 1.3 0.0 0.1 2.0 12.5 12.8 14.4 0 1 86 1.3 0.1 1.4 0.0 0.1 2.0 13.3 10.8 15.2 0 1 87 1.3 0.1 1.4 0.0 0.1 2.1 12.7 11.6 14.7 0 1 86 1.4 0.1 1.4 0.0 0.1 1.5 12.1 11.9 13.5 0 1 89 1.4 0.1 1.2 0.0 0.1 0.5 11.3 9.2 11.7 0 1 96 1.3 0.1 0.9 0.0 0.1 1.0 9.1 8.9 10.0 0 1 90 1.2 0.1 1.7 0.0 0.1 1.5 12.3 13.3 13.7 0 1 89 1.2 0.1 1.0 0.0 0.1 1.0 10.0 0.9 10.9 0 1 i 91 ~ 1.2 0.1 1.1 0.0 0.2 2.0 12.4 1.8 14.2 0 2 I 86 I 1.2 0.1 1.3 0.0 0.2 2.0 13.8 3.1 115.6 I 0 2 87 1.2 0.1 1.4 0.0 0.1 4.1 16.0 2.6 20.0 0 1 I 80 1.2 0.1 1.1 0.0 0.2 0.5 I 13.5 3.9 13.8 0 1 96 1.2

I

, 0.44 0.48 0.44 0.56

I 0.43 0.46 0.45 0.45 0.46 l.04 0.84 0.71: 0.74

, 0.B3 0.84 0.90 0.86 0.59

i 0.62' 0.69

, 0.64 , 0.74,

0.78' 1l.{)11

1.33'

L'lr.

(fl c ,,', :

10 8

10 10 10 8 8 7 9

11 20 21 33 40 62 70

104 54 36 50 30 30 26 20 10

-....J In

Table 26. Whole-soil composition of nine elements and Ti/2r ratio in a Dura1de soil and underlying paleosol on the Montgomery Terrace in Evangeline Parish, Louisiana.

·Depth 1 I Element (meters) I Horizon . Ca I Hg I K J/ Al I Fe .l Si . P r -'- I 1 Ti I Zr I

--------------------k------~------r------ ----------------ppm---------------1 I I I

0.00-0.08 A 0.04 0.04 0.30 11.83 11.94 I 28.22 210 2959 531 0.08-:0.23 I Bw 0.02 0.03 10.28 11.96 0.85 27.71 176 3011 522 0.23-0.38 B/E 0.03 0.03 0.31 2.46 ,1.58 25.96 231 2925 529 0.38-0.53 Btl 0.03 0.03 0.34 3~07 11.42 24.39. 269 2935 507 0.53-0.69 0.05 0.03 0.42 3.18 .1.58 26.18 ·236 3113 538 0.69-0.94 Bt2 0.06 I 0.02 0.50 2.90 1.51 26.00 111 3063 412 0.94-1.19 0.09 0.04 0.52 2.56 1.25 24.23 125 2823 427 1.19-1.45 0.10 0.03 0.55 2.56 1.22 26.89 171 3565 563 1. 45-1. 73 Bt3 0.10 0.03 0.59 2.83 1.30 24.85 165 2844 488 1. 73-1. 90 0.17 0.07 1.00 3.48 2.19 23.16 254 2468 446 1. 90-2.06 0.06 1.11 2.96 1. 75 21.35 320. 2283 488 2.06-2.21

I 0.09 0.02 1.16 3.25 1.66 24.38 343 2579 570

2.21-2.46 Bw 0.05 0.03 1.20 3.32 1.93 23.49 361 2893 599 2.46-2.72 0.09 0.04 1.19 3.44 2.01 23.47 409 2883 544 2.72-2.97 0.06 0.03 1.16 3.30 1.77 22.67 389 2796 550 2.97-3.23 C1 0.10 0.04 1.20 3.58 2.03 25.05 490 3051 543 3.23-3.53 0.14 0.12 1.11 3.52 1.85 24.58 474 3086 550 3.53-3.81 0.12 I 0.06 0.87 2.95 1.48 25.82 359 2825 454 3.81-Lf.11 0.11 0.09 O. L~5 2.60 1.32 26.86 341 2823 539 4.11-Lf.27 C2 0.08 I 0.10 0.25 2.68 1.45 27.48 488 2709 591 4.27-4.42 0.03 0.02

1

0.07 2.48 1. 36 27.53 211 2731 353

4.42-4.57 0.04 0.03 0.()6 2.85 1.63 26.63 171 2737 278 4.57-~ •. 72 2Btb 0.04 0.03 0.05 3.08 1.62 25.75 191 3038 311 4. 72-~ .. 98 0.09 0.13 0.08 3.98 2.26 27.13 313 3153 423 4.98-5.21 0.02 0.02 0.09 3.21 2.35 24.19 257 3014 402

I

I : !

, ,

lRatio tri/Zr

5.57 5.76 5.52 5.79 5.78 7.43 6.61 6.33 5.82 5.53 4.67 4.52 4.82 5.29 5.08 5.25 5.61 6.22 5.24 4.58 7.71 9.84 9.77 7.45 7.50

-....I 0\

I I

SITE 6

This ~top is about 1150 meters north northeast of the site represented by the actompanying morphological description and supporting data. Both are within the same Dexter soil body. The original site was in a churchyard with a s~tting almost identical to the alternate.

77

The Macon Ridge is an elongate north-south trending sandy braided-stream terrace of the Arkansas River extending from near Chi cot in southeastern Arkansas to the Sicily Island Hills area in Louisiana (Saucier, 1974). According to Saucier (1974) it was deposited about 40,000 to 30,000 years BP when the Arkansas River drained areas of Cordilleran glaciation in the Rocky Mountains. He identifies four terrace sublevels with the highest near the eastern edge and progressively lower units to the west. The Arkansas River flowed west of the Macon Ridge until ~bout 3,000 years BP when it broke through the Ridge and entered the Mississippi River further north in Arkansas. Streams now occupying the area west of the Ridge in Louisiana include the Ouachita and Boeuf Rivers and Bayous Bartholomew and Lafourche. Saucier's maps of the Ridge in Louisiana show a small 9rea of Prairie Terrace which includes the highest elevations on the Ridge (32 -41 m.). Eleva-tion maxima on surrounding interfluves are at about 27 - 29 meters. .

bur investigations show that several events following deposition of the sands are. recorded in the near-surface materials and. are determining with respect to the kinds and distribution of soils (figure 17 - 21). Deposit of the sands was followed by a period during which w~ll developed soils formed in the sandy sediments comprisirilg the higher parts of the la.ndscapes. Simultaneously abandoned stream channels and cithe~ low areas received outwash from the ~urrounding area. This more clayey and less sandy material accumulated as a more clayey 'plug' burying soils with minimal development or, in some locals, burying stratified sandy deposits. The presumed slow, long-term accumulation of sediment in the low areas together with the wetter Pedogenic environment in these areas resulted in their having sol Is that are less developed than those on the adjacent higher landscapes. The described landscape was later buried by the late-Pleistocene (Peori~) loess deposits originating in the Mississippi River alluvial plain to the east. The braided~stream morphology is preserved in the loess mantle but becomes more distinct in the direction of thinning loess (east to west). Since loess deposition there has not been extensive erosion of the Ridge and loess stili covers essentially the entire area where it was deposited. The lness deposits form the channel wal Is of most streams draining the area.

The Dexter soil, (Ultic Hapludalf) has formed in high areas'on the preloess landscape near the western margin of the loess where the deposits are thin and contain an admixture of the sandy underlying material throughout. Major characteristics of the Dexter soil are quite analogous to characteristics of the basal mi~ed zone beneath thicker loess deposits overlying the buried sandy soils on the Ridge. Other relationships among the soils are out! ined in the comments pretaining to site 8.

24

23 1./"1 s.... Cl)

+"" Cl)

:2: 22 c:

c 0

~ 21 > Q)

w

20

19

Figure 17. Some relationships between sedim~ntsJ landscapesJ and modern soils in areas with thick loess deposits on the Macon Ridge in Louisiana.

Memphis and Loring soils Calhoun and

soils

V{{{:~q loess

rnm.~ ::::::::::::::

clayey sediments I

sandy braided-stream I I

terrace deposits

I I ,

O.D 0.1 0.2 OJ 0:4 Distance in Kilometers

-....J (Xl

""1 3-QJ -QJ

:2: e22 e 0 --~ t·:':·,·--·· :> CD 21

4.1

20

Figure 18. Some relationships between sediments~ landscapes J and modern soJ!s in areas with moderately thick loess deposits on the Macon Ridge in Louisiana.

lEEE] loess

clayey' alluvium

~} sandy braided-stream terrace deposits

I I I Gigger and I I Necessity soils I ,

I I I i I I I

• . I I I

=-~Lttt]??D~ ~

0.4

Gilbert and Deerford soils


Gigger and Necessity soils

1:6 '-l \.0

en !.... Q)

22

21

~ 20 ...-"'-

c

§ 19 ..-. +-J a > ~ 18 w

Figure 19, Some r~lationshins between sediments, landscapes, and modern soils 'in areas with thin silty deposits on the Macon Ridge in Louisiana.

Foley soils

Dexter soils

tti ~ Loess with ad~ixture of rJ /' underlying sediments

~ Clayey sediments

Im~J Sandy sed'iments

Foley soils

17~

16 · m~~~11i~iiiiii!iiiiiiiliiiiiiiiill~illilllilililllii!iiillililliiliiiiilmlilll!liiiiiiiiiiiiiiiillliiiiiiliiIliiiiiiillimiiiill!lliiiiil!lliilii!lllliiml!llmilli!ii!i!!!11111iillm;;, '" .... I~} ,J! ;;;;;;;;;;;;;;;';":';':';~:':;;;:;;;;;;;;;;;;;;;;;;;;;l;;;;;;;:~ ...................................................... ..•••••••.•••.••••..••••..•••••••.••••••.••••••..•••••••.•••..••••.••••••••••••••.••••••

o 0,1 0.2 0.3 Distance in Kilometers

Eas

00 o

0.4

1

I"

Figure 20 0 Some relationships between sedimentsJ landscapesJ and soils in areas locking identifiable loess deposits on the Macon Ridqe in Louisiana.

rna Si 1 ty alluvium

~ Clayey se(jiments

Iillrnl Sandy sed iments

I I :>. I >. .1 ~--' I I ~ I ~""(/)I I U) <:f) ....... U) ...-. I :i5 0 I Foley soi Is 'I ~ 0 I Liddievi lIe soils U(/) UU)I

Liddieville soils -~ I I (J.) I

~ ll1lli1!!I,I,I!I'IIIIIII'!'i,II,'li"llIlIiltll.,! .. r:.j,~~IIII,jll'I,I'i'I'IIII'III,lllijiIIJf C .....jmmmmmmmmmmmmmmmmmllgggmmgglmll1lmmmmmmmm::::. ..:::::mmmm~mmmmmmgmmmmmmmmmmmm::::~mmr :.

~ 1 J~ i!~~~mJlllllllltllllllllllllll"IIIIIIIIIIIIIIII~llIlllllllllj:!1l1l11IIIIIIIillltlllllllllllllll~lIllmlllm~ll~j~Lll~~l~~mmmllllllllllll1IIIIIlllllllllllllllllllllllllilllllillillllllllllllllllllllllllllm!!llIIIIII!! ~ mHHHmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmHmmmmmmmmmmmm~mmmf~_.

or-( :::::::::::::::::::::::::::!::::::::::::::::::::::::::::::::::::::::::!!:!::::::::::::::::::::::::::::::::::::::!!::::::::::::::::::::::::!:::::::H::::::::::::::::::::::::::::::::::::::::::::::::::::;:::::::::::::::::::::::::::::::=:= w 1 ;:::::::::::::::::::::::::::::::::::::::::::::::::::::::::liE:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::l::::::::::::::::::::::::::::::::::::::::::;:::':::::::::::::::::

............... <> ........ ,. ..... "' .... <> •• " .... "2-D ......................... ~ ••••• ~ ... .,.DO .... D .. " ............................................... ......... " .......... " .................... o ................... c-o ................................ "' ................ " .................................... •••••••• ~." ............. _

................. ., ......................... ~ ......................................... " ...................................................... • ". 0 ....................... 0 ................................. D ................ D." ..... "' ........................ 0 ........................ " ..... 0 .... " .... o."" .................. " .......... '0.,.

gg~g~gggggggggggggggggg~ggHgg;ggggg~gggggggggggggggggggggggggggggggggggggg~~gggg;ggggggg;g~gggggg;ggg~ggggggg;gggggggggggg::::::

l~[I!~I~'ill!!I,ll,jl!llillllllll,'J.!.I',I',,,.II.!II ... 1.11!!lllllililill!!l '!,lll!ll!!II,I'llllllllllilll 1I!lI!III~~iliill~l!ii~i~lil!lililillili'III~"I'lj'liiIli!I~lllli!~!l!~

.......

a 0,4 0.8 1.2 1.6 Distance in Kilometers 00

i-'

0; .:= = c .g ,.. :>

" U

" .~

'" u

'"

LEGEND

Rc,enl alluvium of the Arkansas or Mississippi River

[:::tU Pleistocene ~ge loess

k»>l Plciuocene lfgC braided-wearn alluvium

I 5 miles (Approx.)

We>! Eas.!

110

70

60

50

40

.>< .. ~ u

.:.< .. ~ u

Figure 21. Distribution of loess and other sediments on an east-west traverse across the Macon Ridge from Louisiana Highway 4 bridge at the Beouf River to Vicinity of old church in Franklin Parish, Louisiana.

80

00 N

SITE 6

Macon Ridge Terrace

Dexter Soil (fine-silty, mixed, thermic Ultic Hapludalf)

Location: Two miles northwest of Winnsboro, Louisiana, 310 feet west of highway 869 and 42 feet north of church in SE~, SE~, sec. 8, T.14N., R.7E. (elevation: approximately 22.2 meters)

The Dexter series is comprised of well-drained, moderately permeable soils formed where a thin mantle of Peoria loess contains an admixture of underlying sandy braided-stream deposits.

Formation Soil

Horizon

Ap

Bw

Btl

Bt3

Depth (meters)

0.00-0.10

0.10-0.2S

0.2S-0.61

0.61-0.81

0.81-1.02

Morphology

Brown (lOYR 4/3) silt loam; weak, fine granular structure; friable; many fine roots; medium a~id; clear smooth boundary.

Dark brown (7.SYR 4/4) silt loam; weak, medium sub angular blocky structure; friable; few fine roots; few fine pores; strongly acid; clear smooth boundary.

Yellowish red (SYR S/6) clay loam; surfaces of peds are reddish brown (SYR, 4/4); moderate, medium subangular blocky structure; firm, common fine roots; few fine pores; nearly continuous clay films on faces of peds; few fine black stains on peds; very strongly acid; gradual smooth boundary.

Yellowish red (SYR S/6) clay loam; surfaces of peds are reddish brown (5YR 4/4); moderate. medium subangular blocky structure; firm; few fine pores; thin patchy clay films on faces of peds; common medium black stains on faces of peds; very strongly acid; clear smooth boundary.

Dark brown (7.SYR 4/4) loam; surfaces of peds are reddish brown (SYR4/4); moderate, medium subangular blocky structure; firm; few fine pores; thin patchy clay films on faces of peds; common medium black stains on faces of peds; very strongly acid; clear smooth boundary.

83

84

2Bt4

2Cl

2C2

3C3

1.02-1.32

1.32-1.65

1. 65-2 .03

2.03-2.50

Dark brown (7.5YR 4/4); sandy loam, weak, medium subangular blocky structure; friable; few fine pores; thin patchy clay films on faces of peds; few medium black stains on faces of peds; strongly acid; gradual smooth boundary.

Brown (7.5YR 4/4) fine sandy loam; weak, coarse subangular blocky structure; very friable; few fine black stains on faces of peds; strongly acid; gradual smooth boundary.

Light yellowish brown (lOYR 6/4) loamy fine sand; single grained; very friable; strongly acid.

Stratified braided-stream deposits; predominantly sands and loamy sands that contain some more clayey strata.

85

SITE f} Horizon

Depth Formation (meters)

p

\BW en

+..:> -.-1 en 0 0.. Q)

'0

am 0.25-0.61 E t1- ~

Q)

J...l

93 +..:> en '0 Q)

se '0 -.-1

Bt2 ~ J...l

70 ,0

~ '0

1=1

62.1 ~ Q) en rl

'0 ~ C,) Bt3 1=1

r:n 52.1 cd

~ en [jJ

42.1 Q)

0 rl

1. 02-1. 32 2Bt4 ~

30 -.-1 J...l 0 Q)

20 t P-i

'"d

I: i Q)

:x: 1. 32~1. 65 -.-1 ..,.. - -- 2Cl """

\ 1. 65-2.03 \ 2C2

I =t I I I I I I " CD "'<t e>l (Q CD ts:I N ts:I N CD ts:I "'<t N ts:I ts:I CD ts:I -N ts:I en l'Sl l'Sl e>l 10 ...... ts:I ts:I (T) ts:I 6 . • . to . ts1

ts:I ts:I ts:I ts:I ts:I . N . . ui <d • l'Sl N CD ts:I N ts:I If) ts:I ts:I ts:I N (11 "'<t CD ...... ...... ...... N N (11 "<t ..... N 10 ..... N

PARTICLE SIZE (m i crans)

Figure 22. Clay-free particle size distribution (Coulter Counter and sieve) in a Dexter soil- on the Macon Ridge in Franklin Parish, Louisiana.

Table 27. Particle size distribution in a Dexter soil on the Macon Ridge in Franklin Parish, Louisiana.

Size Class and Particle Diameter (mm) Depth IHorizon~ Total Sand

Silt Very Sand

(2.0- (0.05- Clay Coarse Coarse Medium Fine Very fine :12)

Sand Silt 1 (meters:j Cl.05) 0.002) «0.00 2.0-1.0) (1.0-0.5) (0.5-0.25) (0.25-0.1) (0.1-0.05 )

0.00-0.10 0.10-0.25 0.25-0.61 0.61-0.81 0.81-1.02 1.02-1.32 1. 32-1. 65 1. 65-2. 03

AP 34.8 Bw 23.9 Btl 17.9 Bt2 26.2 Bt3 40.9 2BtLf 59.1 2Cl 73.5 2C2 85.0

54.7 62.5 35.6 39.3 32.8 23.8 15.1 5.7

10.5 13.6 35.6 34.5 26.3 17.1 11.4 9.3

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Pct. of "'·2 mUl

0.0 6.2 , 20.0 8.6 1.6

0.0 3.9 14.2 5.8 2.6 0.0 2.5 10.4 5.0 2.0 0.1 3.5 15.8 6.8 1.5 0.1 5.2 26.1 9.5 0.8 0.0 7.0 37.1 15.0 0.4 0.0 7.1 47.1 19.3 0.2 0.0 8.5 54.7 21.8 0.1

Table 28. Profile distribution trends of Phyllosilicates in the clay-size fraction of a Dexter soil on the Macon Ridge i:n Framkli.n Parish, Louisiana.

Mineral Component Regular inter- Inter-

Chlorotized stratified stratified Depth Soil Vermiculite (Smectite- and

(meters) Horizon Kaolinite Micaceous Smectite (Pedogenic) chlorite?) interlayered

0.00-0.10 Ap xxxxxxx xxxxxx tr xx tr xxxxx 0.10-0.25 Bw xxxxxxx xxxxxx tr xx x xxxxx 0.25-0.61 Btl xxxxxxx xxxxxxx tr x x xxxx 0.61-0.81 Bt2 xxxxxxx xxxxxxx tr x x xxxx 0.81-1.02 Bt3 xxxxxx xxxxxxx x x x xxxx 1.02-1.32 IIBt4 xxxxxx xxxxxxx x x x xxxx 1.32-1.65 nel xxxxxxx xxxxxxx x x x xxx 1. 65-2.03 IIC2 xx.xxxxx xxxxxxx x x x xxx

ex> 0\ .•

Tex-tura1 class

5; 1 5;1 cl cl 1 51 51 15

Depth

Table 29. Selected chemical characteristics of a Dexter soil on the Macon Ridge in Franklin Parish, Louisiana.

Extract able I

acidity I cap .. ___ y Exchangeable DaC12-effec- INH .. - Sum of

Saturation

ations I Ai IH I I Ca ~I K i:-1a I Ai I H TEA tive

;meters)..! ." 1 I I ' rnUliequivaients/100 grarn9- i. .

0.00-0.10 I AP 15.7 I 5.0 4.6 2.0 1.0, 0.5 0.1 0.0 0.3 6.2 3.9 5.8 9.8 0 8 37 0.10-0.251 Bw 16.015.4 4.9 2.2 ! ].0 10.1 0.2 0.0 0.3 5.6 3.8 4.6 9.1 {) 8 38 0.25-0.61 Btl 5.6 4.9 4.3 4.2 1.9 1 0.2 0.1 0.2 0.4 7.5 7.0 9.6 13.9 3 6 46 0.61-0.81 Bt2 15.3 4.5 3.8 2.2 3.7 0.1 0.2 1.8 0.6 10.6 8.6 9.9 16.8 21 7 37 0.81-1.02 Bt3 15.314.4 3.9 1.5 i 3,.1 0.1 0.2 1.5 0.3 8.5 6.7 7.6 13.4 '23 4 37 1.02-1.32 2Bt4 15.4 4.4 3.9 1.0 2.2 0.1 0.1 1.2 D.O 5.4 4.6 5.4 1 8.8 26 0 39 1.32-1.65 2Cl 5.5 '14.5 14.0 0.6 1.3 10.1 0.1 0.3 0.3 4.2 2.6 3.6 6.2 11 12 32 1.55-2.03 2C2 5.5 4.6 14.1 0.7 1.3 0.1 0.1 0.3 0.3 3.9 2.7 3.4 6.0 11 11 35

Cahl£ ' " E~cr. (Exchange- :Organlc i rree

S 'Free i'-

able) , e leo)' 'Fe '(ilr.I·:11

2.0 10.42 12 2 . 2 . , 0 . 54: 6 2.2 11.35

12

0.61.31 12 0.5 '0.90, 16 0.4 ,0.68 14 0.5 ,0.48 I 15 0.5 \0.40: 22

1

Table 30. Whole-soil composition of nine elements and Ti/Zr ratio in a Dexter soil on the Macon Ridge in Franklin Parish, Louisiana.

Depth Element (meters) Horizon Ca I Mg I K I A1 .L. Fe .1 Si P

--------------------%------ ------r------1

0.00-0.10 AP 0.08 0.04 1.27 2.24 1.02 30.09 333 , 0.10-0.25 Bw 0.14 0.09 1.47 2.80 1.21 31.87 399 0.25-0.61 Btl 0.09 0.21 1.39 4.55 2.63 27.32 . 473 0.61-0.81 Bt2 0.11 0.22 1.57 5.11 2.87 30.77 534 0.81-1.02 Bt3 0.08 0.15 1.42 4.11 2.18 28.39 436 1. 02-1. 32 2Bt4 0.07 0.06 1 .. 48 I 3.50 1.64 31. 73 219 1.32-1.65 2C1 0.17 0.l3 I 1.. 94 3.85 1.30 40.99 93 1. 65-2.03 2C2 0.18 0.11 1 .. 81 I 3.55 1.17 39.51 75

1

I I I ! I I i , , , ...

----J------~pm----- ---:=--' ~~ 3213 815 3771 1018 3933 879 3897 887 3126 707 2413 463 2165 517 1596 363

---~-- .----~~-,--

Ratio 'l-i/Zr

3.9 3.5 4.5 4.4 4.4 5.2 4.2 4.4

I 1 .L - ---_.

00 o..-J

88

SITE 7

This stop is at the site originally sampled and represented by the accompanying morphological description and supporting data. Some slumping has occurred since the site was sampled. The Sicily Island Hills have recently been dedicated as a State Wildlife Management area. Before that, private ownership of the .extensive mInIng operations limited acces to other areas. Numerous excellent exposures of the two loesses and underlying gravel are scattered throughout the area.

Some relationships among the geologic materials forming the Sicily Island Hills and surrounding area are illustrated in Figure 23. Chawner (1936) described the Hills as an eastward continuation of the uplands to the west. These hills form the western edge of the narrowest portion of the Lower Mississippi alluvial valley. They are seperated from the hills to the west by the Oucachita River and its alluvial plain. The area is more or less circular in form with maximum elevations of ~bout 80 meters, nearly 60 meters above the Macon Ridge to the east. The hi.lls are capped by two loesses having a combined thickness in excess of 10 meters in places. Citronelle gravels and sands, now removed from much of the area by mining operations, occur immediately below the loess. The Citronelle formation is in turn underlain by the Catahoula formation, a late Oligocene and/or' early Miocene deposit (Snead and McCulloh, 1984).

We ideAtify two loesses at the site. The uppermost 3.8 meters is comprised of the Peoria loess containing an eroded Memphis soil profile. The underlying pre-Peoria loess is about 6.4 meters thick ond contains a paleosol similar in many respects to the Memphis soil above. Beneath the loess is awell expressed paleosol developed in the Citronelle formation. The pre-Peoria 10ess~Citronelle gravels contact zone is an excellent place to observe the basal mixed zone that extends upward into the loess abo~e the 'contact l

•

Below about 7 meters, the pre-Peoria loess is calcareous throughout the matrix and contains gastropod shells. A single 14c date of 27,500 ! 1,200 years BP has been obtained from shell taken from the lower 4art of this zone. Other shell has been extracted for verification dating by 1 C and amino acid techniques.

The soils developed in loess on the Sicily Island Hi lIs are mostly in the Hemphis series (Typic Hapiudaif). The gently sloping topography and more restricted internal soil drainage conditions under which most other soils (except the Natchez) are developed in Peoria loess in the Lower Mississippi Valley are lacking. The Peoria loess is leached free of carbonates throughout and soils having the high base status of the Natchez series (Typic Eutrochrept) have not been observed.

In I.-m ...... m :E c

c o

-+-' ('0 > W

1..ii.J

W > ...... ro CI,)

~

Figure 23, General relationships among geologic materials in the Sicily Island Hills area in Louisiana

50

40

30li

20

10

o o

E ::J ....... > ::J ....... ~

10

L (])

> .~ ... CY-:

10 +-J • r-<

.c u ::J

0

j

L (])

> . ...... ~

10 +-oJ .~ ..

') ~.

Peoria loess) .::~O;:::::::::::::::::::::::::::::\:::::::}Th

I; .... - .... v . "-~---'... _ .. ... .. 6 41G•• C •• .... • ... • 4I .. • .... • • • 9 •• 9 •••• 4" •• 9. 6'. a',

a ... 4 41& j~ .. p .......... • ....... ..

•••• 0 •• ~9 .". a·v .-. a'v .' ell.'" 46~ .6 41. ,. "Oo • .... <CIa. • ... ., ••

' .... " .. &4".'" e ll." .. 9 do 44' ••• 6.' .. "0 4 .. ',,9,6 "".' 6\ 4.".'. - - aT ! cT •• '. .9, t"

I~illllll"., loess

(?) formation

jTertiary deposits ::: ::';:::i::::! :·:;:;::·:·:··.:·x··:····::·:;~:: ::!;::':":.;:.:',-,,: t/V (M 1 oc ene)

, ........ ',' ..... ; ... ; .. , ... " .......................... ~~ ..

'~t~1!~!)~~(~;~i'ihl\fU~~)JI~it{g~W.~~~~~ 4 6 8 10 12


en en Q) o .--.

o ....... L o Q) a..

J

14

Q) u o L L Q) I-

E o Q) L +-J en I

"0 Q) -"0 Q)

...... 0: 0"0 L ...... ..a 0:::

... >. '0 c o U)

c o u o

::F.: ........

E :::J ....... > :::J

........ ....... 10

1-IV > ., .....

0::::

.~

0. 0. .~

(n (/) ...... (/) (/) ...... :E

J

16 00 \0

90

SITE 7'

Loess covered early Pleistocene Terrace (Sicily Island, La.)

Memphis Soil (fine-silty, mixed, thermic Typic Hapludalf)

Location: Catahou1a Parish, Louisiana: abandoned gravel pit in SW~, SE~, SE~, sec. 11, T10N., R7E. (elevation: approximately 73 meters).

The Memphis series is comp~ised of well-drained, moderately permeable soils developed in Peoria loess deposits more than approximately 1.25 meters thick.

Formation Soil

Horizon

A

Btl

. Bt2

Bt3

Bt4

Depth (meters)

0.00-0.07

0.07-0.38

0.38-0.76

0.76-1.14

1.14-2.13

Morphology

Brown, (10YR 4/3) silt loam; weak, medium and fine, angular blocky and granular structure; friable; many fine roots; slightly acid; abrupt smooth boundary.

Strong brown (7.5YR 5/6) silt loam; moderate, medium sub angular . blocky structure; firm; clay films on ped surfaces and in pores; common fine

. roots; strongly acid; clear smooth boundary.

Dark brown (7.5YR 4/4) silt loam; moderate to weak, medium sub angular blocky structure; firm; thin clay films on ped surfaces and in pores; few fine

med1um gradual smooth boundary.

Dark brown (7.5YR 4/4) silt loam; weak, medium and coarse sub angular blocky structure; firm; thin discontinuous clay films on some ped surfaces; thin gray silt coats on some vertical . ped surfaces; mildly alkaline; gradual smooth boundary.

Dark brown (7.5YR 4/4) silt loam; weak, coarse subangular blocky structure to massive; friable; thin discontinuous clay films on some peds; thin gray silt coatings on some vertical ped faces; mildly alkaline; diffuse smooth boundary,

C1 2.13-3.34

C2 3.34-3.80

2Bt1b 3.80-4.40

2Bt2b 4.40-5.02

2Bwb 5.02-5.33

2C1b 5.33-7.01

2C2b 7.01-9.75

2C3b 9.75-10.21

Dark brown (7.5YR 4/4) silt loam; structureless; massive; friable; moderately alkaline in upper part; mildly alkaline in upper part; diffuse smooth boundary.

Dark brown (7.5YR 4/4) to brown (10YR 4/4) silt loam; structureless; massive; mildly alkaline; gradual smooth boundary.

Strong brown (7.5YR 5/6) silty clay loam; moderate, medium subangular blocky structure; very firm; continuous clay films on ped surfaces and in pores; neutral; gradual smooth boundary.

Strong brown (7.5YR 5/6) silt loam; moderate, medium sub angular blocky structure; firm; clay films on ped surfaces and in pores; neutral in upper part to mildly alkaline in lower part; gradual smooth boundary.

Strong brown (7.5YR 5/6) silt loam; weak, coarse sub angular blocky structure; friable; mildly alkaline; gradual smooth boundary.

Brown (7.5YR 5/4) silt loam; structureless; massive; very friable; mildly alkaline in upper part; calcareous; contains gastropod shells; moderately alkaline in lower part; diffuse smooth boundary.

Brown (7.5YR 5/4) silt; structureless massive; very friable; calcareous; contains gastropod shells; strongly alkaline; diffuse smooth boundary.

Brown (7.5YR 5/4) gravelly silt loam; structureless; massive; friable; moderately alkaline; gradual smooth boundary.

'91

92

3A1b

3A2b

3Btb

10.21-10.66 Yellowish brown (10YR 5/4) gravelly sand; structureless; massive; loose; calcareous; mildly alkaline; diffuse smooth boundary.

10.66-11.27 Light yellowish brown (10YR 6/4) gravelly sand; structureless;' massive; loose; calcareous; mildly alkaline; clear smooth boundary.

11.27-11.58 Red (2.5YR 4/8) gravelly sandy loam; moderate, medium and coarse, subangular blocky structure; very firm; seams of material from overlying horizons extend through horizon along some peds. Calcareous on some ped faces; mildly alkaline.

OJ r-n:l U

V')

~

IC2

9\1

e2

72

59

511

40

32

2i

111

SITE 'f


0.00-" 0."'-' /~ ~ --+-~---A

I

0.38- 0.76 8tl

8t2

'------8t3 ~~ ___ 8t4

'-------- C 1

-------C2 '------___ 28t 1 b

'-----___ 2BC 2b "

2Bwb '-'-___ 2C 1 b

,--~ __ 2C2b

!! 8. 38- 8.83 I _

~~ o ')0 () ,r: "~ J''-~ : "'---

~ ~'JC")b ~ :~ Lv I '-"

10.21-10.66 : - fi ; - 3Alb

10.66-10.97

10.97-11.27

11.27-11.58

I I )

.--"""

PARTICLE SIZE (micro~s)

3A2b

Formation

..... e

or-

III III OJ o

n:l ..... . s.....-0''''''' OJ 0 CLIIl

'r-e .,.... n:l

.f.J t: o U

VI III OJ o

n:l 'r- ~

1--j'==" o 0 OJ III

CL 0 ! Q)

OJ r-s... n:l

CL CL

I r::

"ri 10

r--. ~ ",. r:: '-' 0

u (I) 'C rl P (I) •

rl 0 °0 I rl <LI"riHO P ~ ::l Ul o m.o 0 H S <LI ~ H b1)rl "riO&::m U 4-1 .,,: ~

Figure 24.C1ay-free particle size distribution (Coulter Counter and sieve) in a Memphis soil and underlying Paleosols on Sicily Island in Catahoula Parish, Louisiana.

93

Table 31. Particle size cj.istribution in a Hemphis soil and underlying paleosols on Sicily Island in Catahou1a Parish, Louisiana.

~ ~

Depth Horizon, Total

Sand Silt I (2.0- (0.05- Clay

(meters 0.05) 0.002) «0.002)

00-0.07 A 2.9 79.2

I 17.9

07-0.38 Btl 1.7 75.8 22.5 38-0.76 Bt2 1.5 77 .2 21.3 76-1.14 Bt3 ! 0.9 82.2 16.8 14-1.52 Bt4 i 1.3 80.6 18.1 52-2.13

, 1.3 79.1 19.6

13-2. 73 1 C1 1.3 79.0 19.7 73-3.34 1.6 76.5 22.0 34-3.80 I C2 2.0 74.6 23.4 80-4.10 2Bt1b 1.1 69.9 29.0 10-4.40 i 0.8 70.4 28.9 40-4.72; 2Bt2b 0.7

I 86.2 13.1

72-5.02 i 0.6 86.1 13.3 02-5.33 i 2Bwb 0.9 83.7 15.3 33-6.09: 2C1b 1.3 Sl.8 16.S 09-7.011 1.8 85.3 12.9 01-7. 92 1 2C2b 4.8 85.2 10.0 92-8.38 5.9 86.3 7.7 38-8.83 7.7 86.2

I 6.1

83-9.29 7.9 84.5 7.6 29-9.75 9.4 81.5

I 9.1

75-10.2 2C3b 18.5 73.1 8.4 21-10.6E 55.2 37.5 I 7.3 66-10.91 3A1b 89.7 7.1 I 3.2 97-11. 2 3A2b 94.6 2.8 2.7 27-11. Sf 3Btb 82.0 1.2

[ 16.8

I

I I I I -

Size Class and Particle Diameter (mm) Sand ,

Very Coarse Coarse Medium Fine 2.0-1.0) 0,0-0.5) (0.5-0.25) (0.25-0.1 )

Pct. of '" 2 llllU

0.0 0.3 0.7 0.6 0.0 0.1 0.1 0.2 0.0 0.1 0.2 0.2 0.0 0.0 0.0 0.1 0.0 0.1 0.1 0.2 0.0 0.1 0.1 0.1 0.0 0.0 0.1 0.1 0.0 0.1 0.1 0.2 0.0 0.1 0.1 0.2 0.0 0.2 0.4 0.2 0.0 0.1 0.2 0.1 0.0 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.0 0.1 0.1 0.1 0.0 0.1 0.1 0.4 0.8 1.2 0.6 0.6 0.7 1.3 1.1 1.2 1.2 2.9 1.3 1.1 1.8 2.2 1.3 1.1 2.4 2.2 2.0 1.4 3.6 5.4 5.9 2.2

16.7 13.6 18.5 4.2 18.4 30.7· 33.8 5.3

4.8 36.1 48.1 4.4 11.6 42.6 26.4 1.1

Very fine (0.1-0.05 )

1.3 1.4 1.1 0.9 1.0 1.0 1.1 1.2 1.6 0.4 0.4 0.6 0.5 0.9 1.2 1.3 1.6 1.6 1.3 1.5 1.5 1.4 2.2

I 1.5 1.1 i

t 0.4 I , ,

I

I I i I I

I I

Silt Sand

27.3 44.6 51.5 91.3 62.0 60.8 60.7 47.8 37.3 63.5 88.0

123.1 143.5

93.0 62.9 47 .. 4 17.7 14.6 11.2 10.7 8.7 4.0 0.7 0.1 0.1 0.1

Tex-tura1 class

sil s;1 s i1 sil sil sil sil sil sil sic sic sil sil sil s;l s i 1 si s; s; si si sil 1 s s s1

1 1

Table 32. Profile distribution trends of Phyllosilicates in the clay-size fraction of a Memphis soil and underlying paleosol on Sicily Island in Catahou1a Parish, Louisiana.



(meters) Horizon Kaolinite Micaceous Smectite Inter1ayered

0.00-0.07 A xxxxxxxx xxxxx xxxxxx x 0.07-0.38 Btl xxxxxx xxxxxx xxxxxxx x 0.38-0.76 Bt2 xxxxx xxxxxxx xxxxxxx x 0.76-1.14 Bt3 xxxxx xxxxxxx xxxxxxx x 1.14-1.52 Bt4 xxxxx xxxxxxx xxxxxxxx tr 1.52-2.13 xxxxx xxxxxxx xxxxxxxx tr 2.13-2.73 C1 xxxxx xxxxxxx xxxxxxxx tr 2.73-3.34 xxxxx xxxxxxx xxxxxxxx tr 3.34-3.80 C2 xxxxxx xxxxxxx xxxxxxx tr 3.80-4.10 2Btlb xxxxxxxx xxxxx xxxxx xx 4.10-4.40 xxxxxxx xxxxxx xxxxx xx 4.40-4.72 2Bt2b xxxxx xxxxxx xxxxxxxx x 4.72-5.02 xxx xxxxx xxxxxxxxxxx x 5.02-5.33 2Bwb xxx xxxxx xxxxxxxxxxxx tr 5.33-6.09 2C1b xxx xxxxx xxxxxxxxxxxx tr 6.09-7.01 xxx xxxxx xxxxxxxxxxxx tr 7,01-7.92 2C2b xxx xxxxx xxxxxxxxxxxx tr 7.92-8.38 xxx xxxxx xxxxxxxxxxxx tr 8,38-8.83 xxx xxxxx xxxxxxxxxxxx tr 8.83-9.29 xxxx xxxxx xxxxxxxxxxxx tr 9.29-9.75 xxxxx xxxx xxxxxxxxxxx tr 9.75-10.21 2C3b xxxxxxx xxx xxxxxxxxxx tr 10.21-10.66 10.66-10.97 10.97-11. 27 11.27-11.58

95

1 Depth Horizon pH In 1:1 I

i suspension

H2O aGb NKGi Ga

(meter 51 I " . - I ).00-0.07; A 6.2 5.2 4.4 7.7

I ).07-0.38: Btl 5.3 5.6 4.8 6.6 ).38-0.76 I 8t2 6.0 6.8 6.0 6.5 ).76-1.14 i Bt3 i 7.6 7.4 6.8 5.9 1.14-1. 52 i Bt4 I l.52-2.13: 18.2 7.8 7.0 7.9

8.3 7.8 7.0 6.9 I

1.13-2.73 : C1 8.2 7.7 6.8 6.3 I U3-3.34 7.4 7.5 6.6 I 6. 9 I I 1.34-3.80 i C2 7.6 7.4 6.2 15.5

I 1.80-4.10; 28tlb 7.1 7.2 6.3 1 8.7 1.10-4.40 : 7.0 7.2 5.8 9.6 I L 40-4.72 : 2Bt2b 7.4 7.2 ' 5.7 6.3 I , I. 72-5.02 i 7.5 7.2 5.9 6.1 I i.02-5.33 ! 2Bwb 7.6 7.2 5.9 6.2 i.33-6.09 ,2C1b 7.6 7.8 7.2 5.8

I I i.09-7.01 I 8.2 8.1 7.6 7.6 '.01-7.92 12C2b 8.6 8.2 7.8 11.6 '.92-8.38 I 8.6 8.2 7.9 15.6 1.38-8.83 i 8.6 8.2 7.9 15.4 1.83-9.29 : 8.5 8.1 7.8 13.9 1.29-9.75 ' 8.2 8.2 7.8 1 16.5 I~ 75-10.21 2C3b 8.4 8.1 7.6 i 15.3 0.21-10.6p 8.2 7.6 7.4 i 4.5 ,0.66-10.97 3A1b 7.8 7.2 7.2 ,0.5 0.97-11. 27 3A2b 7.4 6.9 6.6 I 0.3 1.27-11.5B 3Btb 7.7 7.1 6.7 i1. 8

I , I

I

Table 33. Selected chemical characteristics of a Memphis soil and underlyin~ Paleosols on Sicily Island in Catahoula Parlsh, Louisiana

Extract able Cation exchange

, ,

I

\0 (J'\

I

i 1 acidity capacity Saturation Cahlg I , Ex t r. I I

Exchangl~able llaC1 2 - effec- NH4- ~um of I(EXChange-iorganiC Fre~slFrep r-Mg K Na I Al I H TEA tive OAc )::ations Ai H Bases able) C ,eo) I Fe '(II'..-Jll)1 " ,

7. I : I I "1~"-' -milliequivalents/100 gram~ , I , % r t,·· ! I I

~ 0.60 : 3.4 0.5 0.1 0.0 0.1 5.0 Ill.8 11.8 16.7 1 70 2.3 I 4.4 0.3 0.3 0.2 0.6 4.3 12.4 12.4 15.9 2 5 73 1.5 I

I : 0.62 ' I , 4.8 0.2 0.4 0.0 0.1 1.0 12.0 12.0 12.9 1 92 1.4 , I : 0.60 I I

i ,

, 0.55 i 4.8 0.2 1.7 0.0 0.1 1.8 12.7 12.7 14.4 1 88

I

1.2 I : 0.1 312 , 5.3

1

0.2 2.1 0.0 0.1 0.7 15.6 15.6 16.2 1 96 1.5 , ' 0.1 ' 0.50 ' 332 I 5.2 0 .. 2 2.5 0.0 0.1 0.4 14.9 14.9 15.2 1 97 1.3 I 0.1 ,0.52 I 376 4.9 0 .. 2 2.4 0.0 0.1 0.4 13.9 13.9 14.2 1 97 1.3 ; 0.0 ; 0.55 354 ,

i 5.3 0 .. 2 2.7 0.0 0.1 0.8 15.2 15.2 15.9 1 95 1.3 i ' 0.1 ! 0.50 354 I 4.4 0 .. 2 2.8 0.0 0.1 1.4 23.0 23.0 24.3 1 94 3.5 , ! 0.0 ; 0.95 312 I : 6.5 0 .. 2 3.6 0.0 0.1 0.8 19.1 19.1 19.8 1 96 1.3 , 0.1 '0.80 I 270 6.8 0 .. 2 3.7 0.0 0.1 1.4 20.4 20.4 21.7 1 94 1.4 i 0.0 : 0.75 ' 312 4.6 0,,2 1.6 0.0 0.1 7.2 12.8 12.8 19.9 1 64 1.4 I ! 0.1 : 0.58 : 292 3.7 0,,1 1.4 0.0 0.1 1.1 11.4 11.4 12.4 1 91 1.6 I I 0.1 10•70 : 292 4.2 0,,2 2.1 0.0 0.1 0.8 12.8 12.8 13.5 1 94 1.5 , 0.1 ' 0.55 , 208 ;

4.8 0 .. 2 2.0 0.0 0.1 0.8 12.9 12.9 13.6 1 94 1.2 I i 0.4 10•50 168 ! , 5.7 0,,2 1.2 0.0 0.1 4.0 14.8 14.8 18.7 1 79 1.3 I , 1. 5 i 0.45 376 5.8 I 0,,2 1.6 0.0 0.1 3.8 19.3 19.3 23.0 1 83 2.0 I ! 6.0 \ 0.40 i 208 4.1 0,,1 1.7 0.0 0.1 3.8 21.6 21.6 25.3 1 85 3.8

I ;18.6 : 0 22 ' 292 ,

3.6 0,,1 1.8 0.0 0.1 3.8 21.0 21.0 24.7 1 85 4.3 24.2 i' I 314 i 1 10•22 i , 3.7 0,,1 1.5 0.0 0.1 4.8 19.3 19.3 24.0 1 75 3.8 I ~9.0 '0.25 I 230 : 4.5 0,,1 1.1 0.0 0.1 4.8 22.3 22.3 27.0 1 82 3.7 I i 9.8 : 0.25 I 252

4.5 0,,1 1.2 0.0 0.1 3.4 21.2 21.2 24.5 1 I 86 3.4 , j 4.0 0.32 250 ,

2.0 0 .. 1 0.4 0.0 0.0 0.0 7.0 7.0 7.0 0 100 2.2 I

10. 0 ,0.12 ' 96 i 1 0.6 0,,1 0.0 0.0 0.0 0.0 1.2 1.9 1.2 0 100 0.8 0.0 • 0.05 ' 120 i 0.3 0,,1 0.0 0.0 0.0 0.0 0.7 1.8 0.7 0 100 1.0 10.0 10.05 ,

I 2.6 0 .. 1 0.0 0.0 0.0 0.0 2.7 6.6 2.7 0 100 0.7 ! 0.0 : 0.45 : 320

I ' i i I : I I I i I

Table 34. Whole-soil composition of nine elements and Ti/Zr ratio in a Memphis soil and underlying paleosols on Sicily Island in Catahou1a Parish, Louisiana.

I Depth

en:", U:: rs) Horizon,

0.00-0.07 0.07-0.38 0.38-0.76 0.76-1.14 1.14·-1.52 1.52-2.l3 2.l3-2.73 2.73-3.34 3.34-3.80 3.80-4.10 4.10-4.40 4.40-4.72 I 4.72-5.02 5.02:"'5.33 5.33-6.09 6.09-7.01 7.01-7.92 7.92-8.38 8.38-8.83 8.83-9.29 9.29-9.75 I

9.75-10.21/ 10.21-10.66, 10.66-10.97) 10.97-11.27; 11. 27-11. 58 1

A Btl Bt2 Bt3 Bt4

C1

C2 2Bt1b

2Bt2b

2Bwb 2C1b

2C2b

2C3b

3A1b 3A2b 3Btb

Element Ca 1 ~'lg T K }, Al I Fe 1 Si

--------------------h------L-------------

0.49 0.46 0.53 0.55 0.58 0.56 0.49 0.40 0.42 0.23 0.23 0.52 0.18 0.23 0.29 0.34 1.72 3.41 1. 07 0.51 0.54 0.45 0.55 0.01 0.00 0.04

0.33 0.45 0.46 0.43 o .4l, 0.47 0.42 0.39 0.43 0.31 0.33 0.45 0.l3 0.32 0.48 0.36 0.79 1.02 0.09 0.06 0.09 0.06 0.25 0.03 0.01 0.05

1. 69 1. 74 1. 78 1.86 1. 76 1.77 1. 74 1.67 1.48 1.04 1.25 1.89 1. 69 1.55 1. 70 1.53 1.45 1.32 1.3Lf 1.3Lf 1.48 1.34 1.15 0,,37 0,,33 0 .. 27

i \

4.60 5.21 5.14 4.93 4.84 5.12 5.01 5.11 5.05 4.70 5.03 4.80 3.55 3.93 445 3.91 3.91 2.66 0.73 1.04 2.60 3.01 2.86 0.61 0.44 2.38 I

2.28 ' 2.69 . 2.58 : 2.35 I 2.29 . 2.43 2.42 2.38 2.32 i

2.37 2.79 2.37 2.12 2.04 2.14 2.05 2.01 1.65 1.23 1.41 2.02 1.68 1.22 0.32 0.18 0.83

32.06 30.61 30.59 30.75 29.68 31.28 33.88 34.01 31:28 31.51 30.48 31. 73 28.54 28.13 2953 27.48 26.12 24.53 24.07 24.34 i

27.19 27.33 34.15 40.35 40.85 34.70

_~ __ J ____ J _____ _ 655 612 564 552 610 542 540 477 461 475 400 492 364 484 520 713 735 663 437 443 586 449 382 119

90 171

---- - f

3401 3238 3360 3788 3792 3658 3403 3594 4168 3454 4033 3967 4251 3890 3719 3318 2970 3177 3591 3303 2671

679 431 529

1163 1057 1072 1030

958 110il 11031

983i 824 952

1129 11004 1109 ll30 1289 1029

902 961 777 763 983 928 645 155 199 132

3.1 3.2 3.2 3,,1 3 .. 5 3 .. 4 3.4' 3.7 4.1 3.8 3.7 3.4 3.6 3.5 3.3 3.8 4.1 3.5 3.8 4.2 3.7 3.6 4.1 4.4 2.2 4.0

I.D '-.J

98 SITE 8

The site represented by the accompanying morphological description and supporting data may not be used for logistical purposes if a more convenient alternate site can be located.

The discussion relating to Site 6 contains an overview of the Macon Ridge and events influencing the present distribution of soils on its surface. Some typical relationships between the modern soils and the different deposits are shown in Figures 17 through 21. The Memphis (Typic Hapludalf), Loring (Typic Fragiudalf), Calloway (Glossaquic Fragiudalf), and Calhoun (Typic Glossaqualf) soils formed in areas where the loess is greater than about 1.25 meters thick and does not contain an admixture of the underlying material throughout. The Memphis and Loring soils occupy higher positions than the Calloway and Calhoun and have developed in areas where the loess is directly underlain by the sandy braided-stream deposits or where the loess is more than 2.5 meters thick if it is underlain by more clayey materials. The Calloway and Calhoun soils developed in areas where the loes~ is underlain by more clayey materials above the sandy braided-stream deposits.

The Gigger (Typic Fragiudalf), Egypt (Aquic Glossudalfs), and Gilbert (Typic Glossaqualf) soils formed where the loess is thinner than about 1.25 meters and the apparant contact with the underlying sediment is within the solum. :he Gigger soils are· on the higher positions where the loess is directly underlain by the sandy braided-stream deposits. Egypt and Gilbert soils are on 10w:r positions where the more clayey deposits lie between the loess and the sandy sediments.

Dexter (Ultic Hapludalf) soils formed where thin loess depdsits are mixed throughout with the sandy underlying braided-stream materials. The Liddievil1e .. (Ultic Hapludalf) and Necessity (Glossaquic Fragiudalf) soils formed ~here there IS

little or no influence of loess because of either, or both, absence of loess deposition or erosion of any 10e~s deposited. Foley and Deerford soils (both Albic Glossic Natraqualfs) are in the lowest positions in these areas. They are only in places where the sandy braided-stream deposits are overlain by more clayey alluvium which in turn is overlain by the silty material. This silty material consists of a ioess-iike iocal alluvium that may have included some loess in places. Necessity soils are on intermediate positions in areas that are less sloping. They

. formed in thin loess or in silty alluvium that also may have included loess in places. The Forestdale soils formed in places where little or no loess or silty alluvium overlies the more clayey alluvium in the low areas on the Terrace.

The presence of high levels of exchangeable sodium in the Natraqualfs is associated with specific soil-parent material-geomorphic relationships. The high levels of exchangeable sodium are associated with the more clayey alluvium that accumulated in low or impounded areas on the braided-stream terrace before loess deposition. In the modern landscape, these are level or nearly level areas that are lower than the surrounding area. The Foley, Deerford, Egypt, and Gilbert soils all have high levels of exchangeable sodium with the solum. Foley and Deerford soils are the predominant soils with high levels of exchangeable sodium in areas of the thinnest loess deposits. They have a natric horizon beginning within 10 to 20 inches. In areas of somewhat thicker loess, Egypt and Gilbert soils have hig.h sodium level.s within the solum. They do not have natric horizons but have high sodium levels beginning within 24 to 50 inches, Soils developed in loess deposits greater thar about 4 feet thick do no have high levels of exchangeable sodium within the solum. However, high levels of sodium are present in the more clayey alluvium beneath the 10esso

" .

EIe~djon

(MSl)

f. ~

,/ ,/ ~~'/-~; 45 MI 7' :Ji-~~r<: ~

'e}slocen18 loamy (ll/utl/um from til, Duachlt(l RIII!!r

Pfelstoun, loamy andc;/aYIIY CoaHc;l Plain ,lui/menU

-ll Ptelstocen, loamy and clayey alluvium from lire Arltanuu Rill"

\ L __ Approximately 40 Km 1,.

NiulMnli ~.1I which in'll! mown blll4JaOcr to iho Iltirld Wrlll~l, Indlcats ithe kinds of soil in follows:

l. liuo lind Perry 1. Debuts lInd libuse 1l. BullSy 19. Perry 25. Forestd;alll 1. Hagerty II. Frluell and Guyton 14. Udalfs 20. Hebert and Portland 26. Idee 3. Groom !II. libuM 15. AllcmMlds 21. Rilla 27. Goodwill 4. Molllcy '10. Debute 16. Sterling ion and Gallion 22. Steriiniion 28. Dexter S. Wri,huvll~ and Groom 11. Guylon alld Cuclila 17. Mer Rouge and Glillion 23. Hebert and Portland 29. Yorktown 6. Late 12 Tiliou and Guyton 11. Heber! and Portland 24. Perry

Figure 25. Soil-Lanscape-Parent material relationships in Morehouse Parish, Louisiana.

WEST CARROLL PARISH

/

/ /

\0 \0

100

SITES

Macon Ridge Terrace

Memphis Soil (fine-silty, mixed, thermic Typic Hapludalf) (Glossic Hapludalf inclusion?)

Location: Franklin Parish, Louisiana in SE~, NE~, sec. 8, T15N" R9E. (elevation: approximately 37 meters)

The Memphis series is comprised of well~drained, moderately permeable soils formed in Peoria loess deposits greater than approximately 1.25 meters thick.

Formation Soil

Horizon

Ap

AB

Bw

Btl

Bt2

Bt3

Depth (meters)

0.00-0.10

0.10-0.23

0.23-0.38

0.38-0.76

0.76-1.37

1.37-1.96

Morphology

Dark brown (lOYR 4/3) silt; weak fine granular structure; friable; pH 5.7; clear smooth boundary.

Yellowish brown (lOYR 5/4) silt; common, fine distinct strong brown (7.5 YR 5/6) mottles; structureless, compact, brittle and firm plowpan; pH 6.6; abrupt smooth boundary.

Dark yellowish brown (lOYR 5/6) silt; common medium faint yellowish brown (lOYR 5/4) mottles; weak, medium subangular blocky structure; friable; few fine black stains on ped surfaces; pH 6.8; clear smooth boundary.

Yellowish brown nOYR 5/6) silt loam; moderate, medium subangular blocky structure; firm; pH 5.7; clear wavy boundary.

Strong brown (7.SYR 5/6) silty clay loam to 1.04 meters, silt loam below 1.04 meters. moderate, medium subangular blocky structure; firm, interior of peds somewhat brittle; few light brownish gray silt coats 2-3 mm thick between peds; pH range from 5.9 at top to 5.0 at bottom of horizon; clear irregular boundary.

Dark brown (7.5YR 4/4) silty clay loam to 1.73 meters; silt loam below 1.73 meters; common medium distinct light brownish gray mottles; moderate coarse prisms parting to moderate medium

,.-j o (jJ

·0 ~ Q) aj,..-i Q) aj HP-< +J Ul'O I Q)

'0 ·ri <lJ H '0 ;::! ·ri ...a aj H bl)

I:Q ~ ·ri

,---.~ ",. ·ri '-"aj

+J ()) ~ bOO aj tJ

Q) Q) • ..1 tJ H aj '..1 H aj H H Q) P-<H

Bt4

Bw

2Bb

2C1

1. 96-2.84

2.84-3.35

3.35-5.00

5.51-5.87

subangular blocky structure; firm; common fine black stains on ped surfaces; common thin light brownish gray silt coats between prisms and peds; pH 5.3; gradual irregular boundary.

Dark bro"m (7.5YR 4/4) silt loam; common medium distinct yellowish brown (10YR 5/4) mottles; moderate, coarse prisms parting to moderate, medium subangular blocky structure; firm; common black stains on ped surfaces; common thin pale brown silt coats between prisms and peds; pH ranges from 5.2 at top to 5.8 at bottom of horizon; gradual wavy boundary.

Dark brown (7.5YR 4/4) silt loam; few medium faint yellowish brown (lOYR 5/4) mottles; weak, medium subangular blocky structure; firm; few fine black stains on ped surfaces; few fine pockets of light gray silt; pH 6.2; gradual wavy boundary.

Dark brown (10YR 3/3) silt loam to 4.34 meters; loam below 4.34 meters; weak, coarse sub angular blocky structure; friable; . few fine black stains on ped surfaces; common fine pockets of light gray silt; pH ranges from 6.5 at top to 7.2 at bottom of horizon; gradual irregular boundary.

Stratified dark bro'Vm (7.5YR 4/4) clay loam to 5.51 meters; sandy loam below 5.51 meters; sand and sandy loam; friable; pH 7.4.

101

SITE 8 102

Depth (meters) Hori zon Formation

leo

I1Il

S9

79

60l 0) r-

~D ~

V> 49

C!-!1.

0.00-0.10

0.10-0.23

0.38:"0.76

1. 04-1. 37

3.,35-3.68

, -I I I I

''____.....--. __ AP

AB

BW

Btl

-Bt2

Bt3

Bt4

BW

5.51-5.87 I 2C2 , ,

Figure 26. ClaY-free particle size 'distribution (Coulter C6unter and sieve) in a Memphis soil and underlying Paleosol on the Macon Ridge in Franklin Parish, Louisiana.

0) I s:::

"C .,.... 0) s:::

"C 'r~r= rd ~+J s- b

...a 0

.,.... o Vl

s::: SO)

"C o E 0) s::: .,.... s:::

'r-~ +J s::: o u Vl Vl 0) o

.,... SO 0)

0...

U • 0) rOlQ)Q ~ U Vl

~ 0 ..--.. S- Q) ('-. S- r~ Q) fU

.j.J 0... 0)

'r- E "C S- ~ 0)

-,-- OJ -,.-I'tI S- SS- .j.J ::::I' o..!Il...a

o. O. O. O. O. 1. 1. 1. 1. 2. 2. 2. 3. 3. 3. 4. 4. 4. 5. 5. 5.

Table 35. Particle size distribution in a ME~phis soil and underlying paleosol on the Macon Ridge in Franklin Parish, Louisiana.

I ... ·-r

TT ! t - Total I

I Sand Silt I

(2. 0-. (0. 05- I (meters 0.05) 0.002)

00-0.10 AP I 7.1 I 82.7 1 10-0.23 AB 7.0

I

1 82.2

23-0.38 Bw I 3.8 85.9 38-0.76 Btl

I

1.3 80.7 , , 1

76-1.04 Bt2 I 3.0 70.0 )4-1. 37 5.3 72.2

I 37-1.73 Bt3 2.9 69.5 73-1. 96 2.8 71.4 ;}6-2.29 Bt4 .3.2 74.3 29-2.56 1.9 77.7 56-2.84 2.6 76.2 34-3.10 Bw 5.1 75.1 LO-3.35 10.8 70.4 35-3.68 2Bb 9.1 71.3 :;8-4. 01 17.0 63.2 )1-4.34

120

•2 62.6

~4-4. 67 36.4 48.1 )7-5.00 33.1 50.0 )0-5.26 2C1 34.0 46.1 ~6-5.s1 29.2 42.8 il-5.87 2C2 72.4 16.3

I I

I I.

j j

Size Class and Particle Diameter (mm) Sand

I

Very Clay l Coarse Coarse Medium Fine

«0.002) 2.0-1.0) 0.0-0.5) (0.5-0.25) (0.25-0.1 ) I

Pet. of'" 2 mm 10.2

I 0.2 1.8 1.6 2.3 10.8 0.2 1.2 1.7 2.7 10.3

I 0.2 0.5 1.1 1.5 0.0 18.0 0.1 0.3 0.6

27.0

I 0.1 0.7 0.8 0.9

22.5 0.4 1.0 1.4 1.6 27.6 0.2 0.6 0.6 0.9 25.8 0.1 0.5 0.7 0.9 22.5 0.3 0.5 0.7 1.0 20.,~ 0.1 0.1 0.2 0.9 21. 2 0.0 0.1 0.5 1.6 19.8 0.1 0.1 0.9 3.0 18.8 0.0 0.1 2.4 7.1 19.6 0.0 0.1 3.8 2.4 19.8 0.0 0.4 3.6 10.4 17.2 0.0 0.0 4.7 12.6 15.5 0.1 0.1 9.5 22.7 16.9 0.0 0.1 7.2 21.5 19.9 0.0 0.1 6.4 22.4 28.0 0.0 0.1 6.2 . 18.0 11. 3 0.0 0.2 10.6 46.4

I I

I Very fine (0.1-0. as )

1.2 1.2 0.8 0.3 0.5 0.9 0.6 0.6 0.7 0.6 0.4 1.0 1.2 2.8 2.6 2.9 4.0 4.3 5.1 4.9

15.2

Silt Sand

I

I 11. 6 11. 7 22.6 46.7 23.3

I 13.6 24.0

I 25.5 I 23.2 I

i 40.9 I 29_3 I 14.7 I 6.5

7.8 3.7

i 3.1 1.3

: 1.5 1.4 1.5 0 .. 2

i

I I I I ,

I I I I I

Tex-tura1 class

5i 5i 5i 5 i 1 5i( 5il 5 i ( 5il 5i-

5 i 1 5 i 1 5 i i 5 i ~ 5; -5 i-5 i-1 1 1 cl 51

.... o w

104

Table 36. Profile distribution trends of Phyllosilicates in the clay-size fraction of a Memphis soil and underlying paleosol on the Macon Ridge in Franklin Parish, Louisiana.



(meters) Horizon Kaolinite Micaceous Smectite Interlayered 0.00-0.10 Ap 0.10-0.23 AB xxxxxxx xxxxxx xx xxxxx 0.23-0.38 Bw xxxxxxxx xxxxx xxx xxxx 0.38-0.76 Btl xxxxxxx xxxxxx xxx xxxx 0.76-1.04 Bt2 xxxxxx xxxxxxx xxxx xxxx 1.04-1.37 xxxxxx xxxxxxx xxx xxxx 1.37-1.73 Bt3 xxxxxx xxxxxxx xxxx xxx 1. 73-1. 96 xxxxx xxxxxxx xxxxx xxx 1. 96-2.29 Bt4 xxxx xxxxxx xxxxxx xx 2.29-2.56 xxxx xxxxxxx xxxxxxxx x 2.56-2.84 xxx xxxxxxxx xxxxxxxxx tr 2.84-3.10 Bw 3.10-3.35 3.35-3.68 2Bb xxxxx xxxxxxxx xxxxxxx tr 3.68-4.01 xxxxx xxxxxxxx xxxxxxx tr 4.01:-4.34 xxxxx xxxx~xxx xxxxxxx tr 4.34-4.67 xxxxx xxxxxxxx xxxxxxx tr 4.67-5.00 xxxxx xxxxxxx xxx~xxxx tr 5.00-5.26 2Cl 5.26-5.51 xxxxx xxxx xxxxxxxxxx tr 5.51-5.87 2C2 xxxx xxxxxxx xxxx:xxxxx tr

Table 37. Selected chemical characteristics of a Memphis soil and underlying Paleosol on the Macon Ridge in Franklin Parish, Louisiana

Extract Depth Horizon pH able Cation exchange 1

(meters).. 0.00-0.10 0.10-0.23 0.23-0.38 0.38-0.76 0.76-1.04 1.04-1.37 1.37-1. 73 1. 73-1.96 1.96-2.29 2.29-2.56 2.56-2.84 2.84-3.10 3.10-3.35 3.35-3.68 3.68-4.01 fi.01-4.34 4.34-4.67 4.67-5.00 5.00-5.26 5.26-5.51 p.52-5.87

AP AB Bw Btl

. Bt2

Bt3

Bt4

Bw

2Bb

2C1

2C2

... ,

In 1:1 aCidity capacity : effee-suspension I EXCllngeable

H20 f aClz JNKCl -c-a-,

Hg K INa I Al ~

I I --mill

BaCI2- NH~- pum of

I _~ TEA tive OAe ations

lents/IOO gram~

5.71 5.0 4.6 6.6 6.1 5.1 6.8 6.1 5.4 5.7 4.6. 3.9 5.9 4.2 3.7 5.0 4.1 3.4 5.3 4.2 3.5 5.3 4.3 3.2 5.2 4.6 3.2 5.7 4.8 3.5 5.8 4.9 3.7 6.1 5.2 3.7 6.3 5.7 4.1 6.5 5.7 4.4 6.6 6.0 4.5 6.9 6.0 ,!t.8 7.1 6.0 5.0 7.2 6.4 5.0 7.3 6.4 5.1 7.1 6.6 4.9 7.4 6.6 5;3

4;2 4.7 3.2 2.5 1.6 1.4 2.4 4.0 3.2 5.3 5.'9 5.5 5.1 4.7 4.9 4.5 4.1 4.5 6.0 8.0 3.9

2.1 2.2 1.2 1.3 1.6 1.9 3.4 4.4 4.2' 4.6 4.5 4. 2~ 3.B 3.4 3A 3.1 2.6 2.9 3.6 4.4 2.6

0.1 0.71 0 0.4 0 O.:~ 0 0.: 0.21 0 O.:~ 0 O. :2 0.2 O. :2 0.7 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.1 I 0

I 7.4 0.0 0.2 5.6 8.21 12.8

0.0 0.2 3.0 8.1 7.6 10.9 0.0 0.2 3.0 5.5 6.2 8.3 0.7 0.5 4.6 5.6 6.4 9.0 3.9 0.6 8.6 8.3 8.1 12.4 4.1 0.5 9.6 8.5 8.1 13.5 4.8 0.7 11.1 12.3 13.4 17 ;9 3.6 0.7 10.1 14.2 13.1 20.0 1.9 0.8 8.1 12.4 13.9 16.9 0.1 0.8 6.6 12.9 14.1 18.3 0.2 0.6 5.6 12.9 11. 7 17.7 0.2 0.4 5.6 11.9 12.1 16.9 0.1 0.5 4.1 11.0 9.7 14.5 0.0 0.3 3.0 9.7 8.2 12.4 0.0 0.3 3.5 10.0 8.4 13.2 0.0 0.3 3.0 9.2 8.1 11.9 0.0 0.2 2.5 7.9 7.1 10.2 0.0 0.2 1.5 8.8 7.8 10.1 0.0 0.2 3.5 11. 2 10.4 14.5 0.0 0.2 4.6 14.5 12.9 18.9 0.0 0.2 2.0 . 7.7 6.4 9.5

I Saturation

Al I iH ~ases

I i. I

0.0 2.7 56 I 0.0 2.4 72

0.0 3.6 64 12.5 8.9 49 47.0 7.2 31 48.2 5.9 29 39.0 5.7 38 25.3 4.9 50 15.3 6.4 52 1.0 6.2 64 1.6 4.6 68 1.7 3.4 67 1.0 I 4.5 72

I 0.0 3.1 76

I 0.0 3.0 73 0.0 3.3 75 0.0 2.5 75 0.0 2.3 85 0.0 1.8 76 0.0 1.4 76 0.0 2.6 79

I I , !

I I

,

Calfi!; , [x t r .

,(Exchange-,Org"n\c Free (rC'C" ;'-I ' '5-i able) , C 'CO~ : F(' t

'\r.,:l1

\ I I ; , , "

I

2.0 ,

2.1 I

2.7 I 1.9 I

I i 1.0 ,

0.7 I 0.7

I

i ,

0.9 0.8 i 1.2 I

I 1.3 I 1.3 , 1.3 ,

i 1.4 I

I 1.4 I , 1.4 1.5 1.6 1.7 I

1.8 I

I 1.5

i : , I I ,

I I i

I ;

, I ,

I I

I !

I

,

0.5 0.7 0.71 0.8 1.1 1.0 1.2 1.2 1.0 1.2 1.1 1.0 0.9 0.7 0.5 0.5

0.0 0.5 , 0.0: 0.6 ' O.O~ 0.7 0.0 i 0.9! 0.0 0.5

I

I , I

!

i

1 i I I

, ,

290 200

33 32 44 50 44 44 56 86

103

114 114 168 135 168

116 116

1-' o \JI

Table 38. Whole-soil composition of nine elements and Ti/Zr ratio in a Memphis soil and underlying paleosol on the Macon Ridge in Franklin Parish, Louisiana.

Depth Element (meters) Horizonl Ca I Mg K. Al I Fe Si P Ti

--------------------%--------------------r

0.00-0.10 AP 0.21 I 0.14 I 3.34 1.34 31.41 677 2748 425 0.10-0.23 AB 0.20 0. 16 1 3.44 1.52 32.77 586 2970 384 0.23-0.38 Bw 0.12 0.08 I 2.89 1.09 30.91 355 2721 343 0.38-0.76 Btl 0.10 0.16 ! 1.23 3.69 1.61 31.56 473 3030 451 0.76-1.04 Bt2 0.09 0.29 I 1.37 , 5.05 2.39 31.07 587 3396 444 1.04-1.37 0.11 0.32 1.50 4.93 2.30 30.39 .472 3380 463 1.37-1. 73 Bt3 0.15 0.42 1.50 , 5.33 2.85 28.09 576 3296 458 1. 73-1. 96 0.21 0.42 1. 45 I 5.07 2.73 27.58 586 3105 449 1.96-2.29 . Bt4 ' 0.28 0.44 1.53 ' 5.17 2.81 28.77 640 3142 471 2.29-2.56 0.30 0.41 1.48 4.83 2.62 27.14 548 3149 420 2.56-2.84. 0.32 ·0.40 1.55 4.93 2.60 28.21 658 3210 509 2.84-3.io Bw 3.10-3.35 3.35-3.68 2Bb 0.36 0.30 1.68 4.36 2.00 30.10 532 2769 537 3.68-4.01 0.34 0.27 1.60 4.24 1.84 29.60 448 2614 470 4.01-4.34 0.29 0.22 1.54 3.90 1.66 28.64 453 2491 482 4.34-4.67 0.34 0.23l 1.71 4.04 1.66 31.33 478 2305 485 4.67-5.00 0.32 0.28 : 1.62 4.l3 1.89 30.05 501 2762 520 5.00-5.26 2C1 [

5.26-5.51 0.38 0.45 1. 73 5.24 2.59 28.21 491 2925 369 5.51-5.87 2C2 0.29 0.21 1.56 3.33 1.48 30.88 399 1581 242

atio i/Zr

6.46 7.73 7.93 6.72 7.65 7.30 7.20 6.92 6.67 7.50 6.31

5.16 5.56 5.17 4.75 5.31

7.93 6.53

I-' a 0'\

107

SITE 9

This stop is at the site originally sampled and represented by the accompanyingmorphological description and supporting data. It was sampled from a fresh roadcut when the southbound lanes of US 61 bypass were under construction. It is very near one of the sites included in Snowden's (1966) work and identified by Snowden and Priddy (1968) as the Standard Loess Section for Mississippi. It is our interpretation that their site was ~ast of the existing roadcut at about the position of the highway median strip. The position of 14C and TL dates (Fig. 27) are shown with respect to the present section and were plotted based on interpretation of narrative descd'ptions by the respective authors.

The information in Figures 8 and 27 indicates the loesses and/or their subunits identified at this site or nearby surrounding area. We id~ntify three loesses, Peoria, Pre-Peoria, and Loveland, each containing a basal mixed zone that is especially apparant in the chemical, physical, and mineralogical data. The' mixed zone at the base of the Peoria loess corresponds in position to the Roxana (West et ale 1980). Those workers identified thrcker (1.7 meters) Roxana loess deposits on Crowley·s Ridge i,n Arkansas. If Roxana loess is present at this or other sites observed locally or southward to the Gulf Coast, the amounts are too small to exceed the thickness of the basal mixed zone between the Peoria and Pre-Peoria loesses. The third loess (Loveland)' is almost 3 meters thick and lies about 1 meter below the level of the highway.

The deeply incised and steeply sloping "River Hills" areas having thick Peoria loess deposits are comprised mostly of soils in the Memphis (Typic Hapludalf) and Natchez (Typic Eutrochrept) series. At ~reater distances normal to the Mississippi River other soils become dominant as the loess mantle thins and topography is more gently sloping. Major soils in such an ideal toposequence normal to the river include Natchez - Memphis - Loring (Fragiudalf) - Grenada (Fragiudalf) - Calloway (Fragiudalf) - Calhoun (Glossaqualf).

The site and nearby roadcuts to the south afford excellent opportunities to observe the basal mixed zone o For example, at the site the zone immediately above the B horizon of, the soil developed in the Pre-Peoria loess contains visible fragments from the underlying B horizon at distances of more than 0.5 meter above the ·contact'. South of the site (.<.1 Km) Peoria loess directly overlies a buried soil developed in very sandy deposits containing a buried soil with an argill ic horizon comprised of distinct lamellae. There the admixture of sand extending some distance upward into the base of the loess is especially apparant.

The sandy and gravelly materials underlying the loess and containing a well expressed Paleosol is the Citronelle formation (Snowden, 1966). The Citronelle formation, named by Matson (1916) has been considered PI iocene in age by Berry (1916). However, most workers since Roy (1939) have considered it Pleistocene or PI iocene - Pleistocene in age (l,e, Fisk, 1949; Doering, 1958). According to Doering the sands and gravels in the vicinity of the site belong to the Lissie formation which he correlated with Fisk·s Bentley (Yarmouth Interglacial) or Montgomery (Sangamon Interglacial).

108

UJ H OJ ~ OJ •

::<::

~ 'r!

,.c: ~

~ ~

1

o~----------------------------------~ Peoria loess containing Memphis Soil.

2~-------------------

4.

8-

0

Peoria Loess

Snowden's (1966) date of 17~850 yr. (BP). (?) •

(Snowden's (1966) date of 19 ~ 200 yr. BJi,) • (?)

---~---~------------Basal Mixed Zone (22,600 BP ~?)

12 Snowden's (1966) dates (25~~OB)(?)

Pre-Peoria loess

~ ~75,000rto h95 ,000 yr·lBP '984(? L~at~~~Jo~~~~~~~~ __ ~

r()::Icl

base

I I Basal Mixed Zone . l~----~----~~----~~----------------~

Loveland (?) loess (120,000 to 135,000 yrs. BP dates of Johnson et a1., 1984 (~)

~-----------------1& Basal Mixed Zone

(?) , Early Pleistocene Terrace Citronelle (?) Formation

18-1---'--;c'Fo""""n~ L.. aF-L IF. n"'l~ l~""'nC7 g-~D~,TI u-.r--~. IF.. e"F-~ Q~.7'-S ;H'r 0' IF_+·_~. ~~-~-~-~--~-~

Figure 27. Mississippi Standard Loess Section showing approximatY4po~ition of material dated by C and TL methods.

(Note: Positions were plotted on basis of descriptive material in reference cited. Loesses and mix~d zones identified correspond to those of Miller et a1., 1982).

SITE 9

Mississippi Loess Standard Section

Memphis Soil (fine~silty, mixed. thermic Typic Hapludalf)

Location: Warren County, Mississippi; West side of u.S. Highway 61 bypass in north edge of city of Vicksburg; NW~, NE~. NE~. irregular sec. 9, ~16N, R4E. (elevation approximately 116 meters).

Formation

..-I OM o UJ

Soil Horizon

Ap

Bt

Bt2

Bw

C1

Depth (meters)

0.00-0.20

0.20-0.51

0.51-1.22

1. 22-1. 83

1.83-11.43

Morphology

Dark yellowish brown (10YR 4/4) silt loam; moderate fine and medium subangular blocky and granular structure; friable; consists of mixed A and Bt horizon material; strongly acid; abrupt smooth boundary.

Dark yellowish brown (10YR 4/4) silt loam ped exteriors and yellowish brown (10YR 5/4) ped interiors; moderate, fine and medium, subangular blocky structure; firm, continuous clay films on ped surfaces and in pores; many fine and medium pores; common, fine roots; strongly acid; gradual, smooth boundary.

Yellowish brown (10YR 5/4) silt loam with dark yellowish brown (10YR 4/4) clay films on many ped surfaces and in pores; continuity and thickness of clay films decrease ~·lith depth. Friable; common fine and medium roots; COW.!llan

fine and medium pores; medium acid; diffuse smooth boundary.

Yellowish brown (10YR 5/4) silt; weak, coarse, subangular blocky structure; friable; mildly alkaline; diffuse smooth boundary,

Yellowish brown (10YR 5/4) to light yellowish brown (10YR 6/4) silt; massive; friable; contains calcareous gastropod fossils; contains calcareous concretions; calcareous; neutral (pH 7.3) to moderately alkaline (pH 7.9) reaction in different subhorizons, gradual smooth boundary.

109

110

C2

2Bt1b

2Bt2b

2Bt3b

11.43-12.04 Pale brown (10YR 6/3) silt loam; otherwise like overlying material; clear. smooth boundary. Contains admixture from underlying 2Bt1b.

12.04-12.34 Brown (7.5YR 5/4) silty clay loam; moderate medium sub angular blocky structure; firm; continuous clay films on ped surfaces and in pores; neutral; calcareous in places on some ped . surfaces; clear smooth boundary.

12.34-12.95

12.95-13.51,

Brown (7.5YR 5/4) to yellowish brown (10YR 5/4) silt loam; moderate, medium, sub angular blocky structure in upper part grading to weak, medium and coarse, sub angular blocky structure in lower part. firm; clay films on ped surfaces and in pores decrease in thickneps and continuity with depth; calcareous; neutral in upper part; mildly alkaline in lower part; gradual smooth boundary.

Yellowish brown (10YR 5/4) silt loam; 'weak, coarse sub angular blocky structure to massive; friable; thin discontinuous clay films on some ped surfaces. Calcareous; contains some gastropod shells; mildly alkaline; diffuse, smooth boundary~

2Bwb 13.51-13.92 Pale brown (10YR 6/3) to yellowish brown (lOYR 5/4) silt loam; massive; friable; calcareous; contains gastropod shells; mildly alkaline; gradual smooth boundary.

3Bt1b

3Bt2b

3Bt3b

3Bt4b

3C

4Btb

13.92-14.22 Yellowish red (5YR 5/6) silty clay; strong, medium and fine; subangular blocky structure; continuous clay films; very firm; neutral; gradual, smooth boundary.

14.22-14.38 Yellowish red (5YR 5/6) silty clay loam; common, fine and medium light brownish gray (lOYR 6/2) mottles; moderate, medium subangular block structure; firm; clay films on many ped surfaces; calcareous; neutral; diffuse, smooth boundary.

14.38-14.68 Same as above horizon except silt loam; neutral; gradual smooth boundary.

14.68-15.90 Reddish brown (7.5YR 5/4) to yellowish red (7.5YR 5/6) silt loam; weak, medium subangular blocky structure; firm; thin discontinuous clay films on some peds; calcareous in some parts and mildly alkaline to 15.29 meters depth; noncalcareous and mildly alkaline below 15.29 meters. Gradual smooth boundary.

15.90-16.81 Yellowish red (5YR 5/6) silt; weak,· coarse sub angular blocky structure; friable; common fine black concretions. Slightly acid in upper part; neutral in lower part; gradual smooth boundary. Contains admixture from underlying 48tb.

16.81-17.12 Yellowish red (5YR 5/6) silt loam; moderate, medium subangular blocky structure; firm; clay films on ped surfaces; common fine black concretions; slightly acid.

111

112

100

00

80

70

fro

~I 50

o~1 40

33

20

1: I

Depth (meters)

0.20- 0.5

3.30- 3.81

SITE 9

Horizon ----

Btl

Bt2

BW

BC

Cl

~=

PARTICLE S1ZE (microns)

Formation

'r-0 Vl

t:: s-(l)

""0 0 E

Ol t::

'r-t::

'r-co +-l t:: 0 U,

Vl Vl (l) 0

co 'r-s-o (l)

0...

Figure 2B. Cla1y-free particle size distribution (Coulter Counter and sieve) in a Memphis soil and underlying Paleosols in Vicksburg, Mississippi (Continued next page).

SITE 9 (Cont.)


1.1~4~ C2

12.04-12.34

12.65-12.95

2Bt3b

101il

fro 2Bwb

811 13.77-13.92

711

3Btlb 52

14.07-14.22 Q)

51il r-rtl

40 u 3Bt2b ~f")

o~ 31il

20

Hl

Iil

J Figure28. (continued) ClaY-free particle size distribution (Coulter Counter

and sieve) in a Memphis soil and underlying Paleo&ols in Vicksburg, Mississippi.

113

Format; on

'r-rtl +l C o U

Vl Vl r(]) 0 o Vl r- 0

(]) rtl r

'r- rtl S-o.. o (])"'O

0.. (]) I 'r-

(]) ss- :::l

0.. .0

Vl Vl (]) . Or-.-0

Vl ---.. 0 .C'-. 0)

rtl "'00.. c' rtl"'O

.--(]) (]).,....

> so :::l -l .0

O'l C

QJ or- • cc..-w·"'" 0 U rei Vl O+-lo +-lcO) VlOr

'r- U ro (]) Cl.. r-O)

·o..U"'O rtl(lJ

(lJ S-'r+-lS-Srtl(]):::l -l+l.o

Table 39. Particle size distribution in a Memphis soil and underlying paleosols in Vicksburg, Mississippi.

Depth Size Class and Particle Diameter (mm) ~or-i~:~1- -- . Tntrll

. I (meters

Sand

I I ,

Sand Silt Very (2.0- I (O.O~- Clay Coarse Coarse Medium Fine Very fine 0.05) : O .. OOL) «0.002) 2 .. 0-1.0) (1. 0-0.5) (0.5-0.25) (0.25-0.1 ) (0.1-0.05 )

i , Pct. of ~ 2 mm

.00-0.20 I AP

.20-0.51 Btl

.51-1.22 Bt2

.22-1.83 Bw

.83-2.29 Bc

3.3 77 .5 1 18.8 0.0 0.1 0.2 0.3 2.7 5.1 81.5 I 13.4 0.1 0.2 0.4 0.6 3.9 4.0 86.2 I 9.8 0.1 0.1 0.1 0.2 3.7 i

, 4.2 88.5 I 7.3 0.1 0.2 0.1 0.1 3.6 .29-2.79 C1 79-3.30

3.4 88.0 [ 8.6 0.1 0 .. 1 0.1 0.1 3.4 3.2 90.0 I 6.8 0.0 0.1 0.1 0.1 3.0

30-3.81 3.6 89.5 6'.9 0.1 0.1 0.1 0.1 3.5 81-4.31 3.5 89.6 6.9 0.0 0.1 0.1 0.1 3.3 31-4. 72 1

72-5.331 33-5.94;

3.6 91.4 5.0 0.0 0.0 0.1 0.1 3.6 I

3.6 89.4 I

7.0 0.0 0.0 0.1 0.1 3.5 4.9 87.9 7.2 0.0 0.0 0.1 0.1 4.8

94-6.55. 4.0 89.7 6.3 0.0 0.0 0.1 0.1 3.9 55-7.16 4.2 89.2 6.6 0.0 0.0 0.1 0.1 4.1 16-7.77'

I

77-8.28 i 4.2 90.7 I 5.1 0.0 0.0 0.1 0.1 4.2 3.9 90.0 I 6.1 0.0 0.0 0.1 0.1 3.8

28-8.79 :. 79-9.30 ! 30-9.80 i 80-10.2~ 21-10.8 82-11.4

4.5 88.1 7. ~f 0.0 0.1 0.1 0.1 4.4 4.2 89.4 6. Lf 0.0 0.1 0.1 0.1 4.1 3.9 91.3 4.8 0.0 0.1 0.1 0.1 3.8 4.9 91.2 3.9 0.1 0.1 0.1 0.1 4.8 5.4 90.7 3.9 0.1 0.1 0.1 0.1 5.2 3.3 90.0 6 -1 0.1 0.1 0.1 0.1 3.2 • I

43-11. 7~ C2 4.9 82.0 13.1 0.0 0.1 0.1 0.3 4.4 73-12.0~ 04-12.3 2Bt1bl 34-12.6 2Bt2b

4.1 79.5 16.4 0.0 0.1 0.2 0.4 3.4 2.5 64.7 32.8 0.0 0.0 0.1 0.2 2.3 3.0 72.8 24.2 0.0 0.1 0.1 0.2 2.7

65-12.9 95-13.2~ 2Bt3b 26-13.5 51-13.7 2Bwb

4.0 75.3 20.7 0.0 0.1 0.1 0.1 3.8 4.5 77 .6 17 .9 0.0 0.1 0.1 0.1 4.4 5.8 79.7 14.5 0.1 0.1 0.2 0.5 5.1 6.9 77 .6 15.5 0.0 0.1 0.4 0.7 5.8

I \

I

~ Sand

I I 23.5

16.0 21.6 21.1 25.9 28.1 24.9

I 25.6 '25.4

I 24.8

I 17 .9 22. Lf

I 21. 2 21.6 23.1 19.6 21. 3 23.4 18.6 16.8 27.3 16.7 19.3 25.9 26.0

I 18.8 I 17.2 i 13.7

I 11.2 i

I

Tex-tura1 class

sil s i 1 si

• si [ s; si si si si si si si si si si si si si s; si s; sil sil si cl

. sil ',. sil , s i 1 sil sil

>-' >-' +-

Table 39. (continued) Particle size distribution in a Memphis soil and underlying paleosols in Vicksburg, Mississippi.

Depth

I -- -- T iHorizonr I

(meters

i 13~77-13.9~ l3.92-14.0~ 14.07-14.22 14.22-14.3i .14.38-14.6 14.68-14.9

14'98-15'2~ 15.29-15.6 15.60-15.9 15.90-16.2 l6.20-16.51 l6.51-16.81 16.81-17.12

1

! 3Bt1b:

3Bt2b l

3Bt3b: 3Bt4b

1

3Cb

4Btb

Sand (2.0-0.05)

5.4 3.5 3.0 3.0 3.4 4.1 4.6 4.5 6.8 6.5 6.8 7.4 8.9

Total

I Silt I I (0.05-

I i O. 002 ) i

i

72.0 1 49.5

47.6 I 64.0 I 73.0 I

78.1 I 80.9

80.7 I

78.9 84.9 88.0 87.2 71.8

I I

I

I ,

I I

Size Class and Particle Diameter (mm) t Very Sand Silt Sand Tex-

Clay Coarse Coarse Medium Fine Very fine tural «0.002) 2.0-1.0) (1.0-0.5) (0.5-0.252 (0.25-0.1 ) (0.1-0.05 ) class

, Pct. of "- 2 lUlU

22.6 0.0 0.1 0.3 0.6 4.5 l3,,3 47.2 0.0 0.1 0.2 0.4 2.9 14 .. 1 49.4 0.0 0.1 0.1 0.3 2.6 15 .. 9 33.0 0.0 0.1 0.1 0.3 2.7 21.3 23.6 0.0 0.1 0.1 0.1 3.3 21.5 17.8 0.0 0.0 0.2 0.1 3.8 19.0 14.5 0.0 0.1 0.1 0.2 4.2 17.6 14.8 0.0 0.0 0.1 0.2 4.3 17.9 14.3 0.0 0.0 0.1 0.2 6.5 11.6

8.6 0.0 0.1 0.1 0.2 6.3 13.1 5.2. 0.0 0.0 0.1 0.3 6.5 12.9 5.4· 0.0 0.0 0.2 0.4 6.8 ll.8

19.3 0.1 0.2 0.8 1.6 6.3 8.1

i I

,

I

I I--'

116

Table ,40. Profile distribution trends of Phyllosilicates in the clay-size fraction of a Memphis soil and underlying 'paleosols in Vicksburg, Mississippi.

Depth (meters)

Soil Horizon

0.00-0.20 Ap n.20-0.51 Btl 0.51-1.22 Bt2 1. 22-1. 83 Bw 1. 83-2.29 BC 2.29-2.79 C1 2.79-3.30

Kaolinite

xxx xxx xxx xxx xx xx

Mineral Component

Micaceous

xxxx xxxx xxxx. xxxx xxxx xxxx

Smectite

Interstratified

and Interlayered

xxxxxxxxxxxx x xxxxxxxxxxxx x xxxxxxxxxxxx x xxxxxxxxxxxx x xxxxxxxxxxxxx x xxxxxxxxxxxxxx tr

Almost identical diffractograms in fifteen horizons between 2.79 and 10.82 meters

10-21-10.82 10.82-11.43 11.43-11. 73 11. 73-12.04 12.04-12.34 12.34-12.65 12.65-12.95 12.95-13.26 13.26-13.51 13.51-13.77 13.77-13.92 13~92-14.07 14.07-14.22 14.22-14.38 14.38-14.68 14.68-14.98 14.98-15.29 15.29-15.60 15.60-15.90 15.90-16.20 16.20-16.51 16.51-16.81 16.81-17.12

C2

2Bt1b 2Bt2b

2Bt3b

2Bwb·

3Bt1b

3Bt2b 3Bt3b 3Bt4b

3Cb

4Btb

xx xxx xxxx xxxxxx xxxxxxx xxxxxx xxxxx xxxxx xxxxx xxxxxxx xxxxxxxx xxxxxxxxx xxxxxxxxx ~~","..,.,."U"'''U''' .... r ~.n.~.n..n.AAA

xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxx xxxxxxx xxxxxxx xxxxxx xxxxx

xxxx xxxx xxxx xxx xxx xxx xxx xxxx xxxxx xxxx xxxx xxxx xxxx XXXXX xxxxx xxxxx xxxxx xxxxx xxxxx xxxxx xxxx xxxxxx x'Xxxxx

xxxxxxxxxxxxxx tr xxxxxxxxxxxxx tr xxxxxxxxxxx x xxxxxxxxxx x xxxxxxx xxx XXXXXXXf{ xxx xxxxxxxxx xxx xxxxxxxxx xx xxxxxxxxx x xxxxxxx xx xxxxxx xx xxxx xxx xxxx xxx XXXX xxx xxxx xxx xxxx xxx xxxx xxx xxxxx xx xxxxxx xx xxxxxx xx xxxxxxx xx xxxxxxx x XXXXXXXX x

o o o 1 1 2 2 3 3 4 4 5 5 6 7 7 8 8 9 9

10 10 11 11 12 12 12 12

Table 41.Selected chemical characteristics of a Memphis soil and underlying Paleosols in Vicksburg, Mississippi.

I [Extract I I' r Depth Horizon pH able Cation exchange Ii!

In 1:1 i !acidity capacity Saturation Ca/Hg, I ! EHr. suspension I Exchangeable ! BaC1 2- effec- NH 4- pum of I (Exchange- ,OrganiC, Fre~S !Free i'-

H20 aC1 2 NKC1 I Ca 1'~K INa I Al I H '1 TEA tive OAe ations Al H luases able) I C :C0 3 [Fe (nr.l'"l r_: I I I I I I "~r-, ,meters)': . milliequivalents/lOO gram&--- 7. I i. J,

.00-0.20 1 I I I I

.20-0.51! Btl 15.3 5.0 4.1 16.2 4.0 0.1 0.2 0.2 0.4 5.0 21.1 12.8 26.1 1 2 78 4.0 I 0.67: 270

.51-1.221 Bt2 6.0 5.7 5,,1 18.4 . 3.8 0.1 0.1 0.0 0.3 5.0 22.7 11.9 27.7 1 81 4.8 . ,0.66, 284

.11-1.83, Bw 7.8 7.6 7.1 19.8 4.0 10.1 0.2 1.3 24.1 8.5 25.4 95 5.0 20.7,0.48 44 i

.83-2. 291 Be 8.0 7.7 7.2 20.2 4.4 \ 0.1 0.1 0.0 24.8 9.1 24.8 100 5.0 15.9 0.40 40 I

.29-2.79. Cl 8.1 7.7 7.2 17:0 5.2 0.1 0.1 0.4 22.4 8.1 22.8 98 3.3 19.1 i 0.39 32 ;

.79-3.30 I 8.0 7.7 I 7.3 17.8 4.7 0.1 0.1 1.3 22.7 7.1 24.0 95 3.8 22.3.0.34 40 '

.30-3.81 II 7.9 7.8 7.3 18.3 3.9 0.1 0.2 5,.4 22.5 6.8 27.9 81 4.7 22.1 10.29: 35 :

.81-4.31 8.1 7.7 7.2 15.6 3.9 0.1 0.2 2.5 19.8 7.1 22.3 89 5.0 20.0 10.30 54 i

.31-4.72 I 7.9 7.8 7.3 17.5 2.8 0.1 0.2 1.2 20.6 5.5 21.8 94 6.2 24.0,0.34; 10

.72-5.33 7.8 7.7 7.2 17.3 3.8 0.1 0.3 1.7 21.5 7.4 23.2 93 4.6 18.5 10.30 40 I

.33-5. 94 1 7.9 7.7 7.3 15.8 3.5 0.1 0.1 8.0 19.5 7.2 19.5 100 4.5 17.1 0.28, 87 :

.94-6.55 7.87.6 7.3 16.4 3.1 0.1 0.1 1.7 19.7 6.5 21.4 92 5.3 18.20.31.74

.55-7.16 7.8 7.7 7.1 17..8 3.6 0.1 0.2 1.7 21.7 7.0 23.4 93 4.9 20.4 0.27: 74

.16-7.771' 7.9 7.6 7.3 17.0 3.0 0.1 0.1 1.7 20.1 5.7 21.8 92 5.7 21.4 0. 32 i 50 I

.77-8.28 7.8 7.5 7.3 16.3 2.8 0.1 0.1 0 19.3 5.8 19.3 100 5.8 21.0 0.27 74 , ,28-8.79

1

7.8 7.4 7.4 13.5 3.8 0.2 0.1 0 17.6 6.6 17.6 100 3.6 22.7 0.21 127 .79-9.30 7.8 7.5 7 .. 3 13.9 3.4 0.1 0.1 0 17.5 5.7 17.5 100 4.1 31.6 0.24 84 ,30-9.80 17.8 7.4 7 . .4 16.4 2.6 0.1 0.2 0 19.3 4.4 19.3 100 6.3 31.2 0.22 50 80-10.21 7.6 7.3 7.4 121.0 3.7 0.1 0.3 0 25.0 4.4 25.0 100 5.7 33.5 0.19 34 ,21-10. 82

1 7.67.4 7.4 !121 . 9 4.0 0.1 0.4 1.7 26.3 4.0 28.0 94 5.5 34.20.18 34

82-11.43 7.7 7.4 7.4 21.6 4.8 0.1 0.5 2." 26.9 5.1 29.0 93 4.5 31.2.0.21 50 43-11. 73

1 C2 7.6 7.5 7.2 20.4 7.9 0.1 0.9 1.3 29.3 8.8 30.6 96 2.6 8.4 0.31 112 73-12.04 7.6 7.6 7.1 14.2 6.8 0.1 (J.8 3.3 21.9 0.5 25.2 87 2.1 4.8 0.44 44 04-12.341 2Btlb 7.2 7.1 6.4 10.0 B.9 0.2 0.4 4.2 18.5 7.0 22.7 81 1.1 0.73 5 34-12.65

1 2Bt2b 7.4 7.3 6.4 9.3 8.0 0.2 0.3 3.3 17.8 5.2 21.1 84 1.2 0.57 10

65-12.95 7.7 7.6 6.8 9.7 7.2 0.2 0.2 1.7 17.3 3.6 19.0 91 1.3 0.49 5 95-13.26\2Bt3b 7.9 i 7.7 7.0 11.0 6.8 0.2 0.2 I 0.8 18.2 3~2 19.0 I 96 1.6 3.4 0.41 5

I-' I-' '-J

Depth

(meters)·

13.26-13.51 13,51-13.7 13.77-13.9l 13.92-14.0i 14.07-14.22 14.22-14.31: 14.38-14. 6E

14'68-14'9~ 14.98-15.2 15.29-15.6 15.60-15.9 15.90-16.2 16.20-16.51 16.51-16.81 16.81-17.12

Horizon

.. -

2Bwb

3Bt1b

3Bt2b 3Bt3b 3Bt4b

3cb

4Btb

pH In 1:1

suspension H20 ~aC12 ,~NKCl

7.3 7.2 7.0 7.4 7.2 7.1 7.4 7.3 7.1 7.3 7.1 6.5 7.3 7.1 6.3 6.6 6.6 5,9 7.6 7.6 7.1 7.47.5 6.8 7.3 7.7 7.1 7.5 7.4 6.7 7.3 7.0 6.4 6.5 6.3 5.6 6.5 6.2 5.2 6.7 6.5 5.7 6.4 6.3 5.4

Ca

t-' t-' 00

Table, 41 (Continued) Selected chemical characteristics of a Memphis soil and underlying Paleosols in Vicksburg, Mississippi.

Exchangeable Mg I KINa Al

I 1 I

H

Extract able

acid i t Y f-:=-:-...;c::;.:a;c:=..":.<., __ -:-BaC12- effec- urn of TEA tive ations

,. i I I I

Saturation i Cahlg Ii: I Exu.

I '1,(EXChange-!organiC! Fre~S I cree I i'- I

R Fases I able) ~_;_~O_) i F!" '(llr""'II) Al

----:---~--mm:lll JLequivalen ts /100 grarns---'------- I---:;~ ~~ i'~""

9.6 6.0 7.2

1L 1 11.6

9.2 12:9 7.8

10.2 7.2 5.1 4.4 4.2 6.8 7.4

5.9 4.7 5.4 9.4

1 10.6 , 8.2

7.5 5.4 6.2 5.3 4.1 3.5 3.4 5.5 6.1

0.1 0.1 0.1 0.2 0.2 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.0 0.1 0.2

0.2 0.1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.2 0.2 0.2 0.3

1.7 2.5 1.7 3.3 3.3 2.5 0.0 3.3 2.1 ' 2.9 5.0 1.3 1.3 2.1 2.9

15.8 10.9 12.9 20.9 22.6 17.8 20.8 13.5 16.7 12.8

9.4 8.1 7.9

12.6 14.0

11.2 9.8

10.5 18.7 20.8 15.5 14.0 10.4 11.7 10.4 8.0 6.9 6.6

11.2 10.9

17 .5 13.4 14.6 24.2 25.9 20.3 20.8 16.8 18.8 15.7 14.4 9.4 9.2

14.7 14.9

90 1 .6 I 2.7 I 0.38 81 1.3 2.1 ; 0.32 88 1 .3 I 0.44 I 86 1.2 : 0.901 87 1.1 '0.97 88 1.1 ;0.61

1 1 00 1 .7 4 .7 ,0.45

80 I 1 .4 : 0.29, 89 1.6 3.0 0.38' 81 1.4 ;0.34 65 1.2 • 0.30, 85 I 1.3 0.31: 86 1.2 ; 0.21: 86 1.2 : 0.21 i

94 1.2 10.24' ;

20 28 5

10 12 13 10 19 22 24 32 19 25 29 19

Table 42. Whole-soil composition of nine elements Paleosols in Vicksburg, Mississippi.

and TijZr ratio in a Memphis soil and underlying

Depth I Element ~atio (meters) Horizon Ca I Hg I K J Al l Fe J Si -~--J-----l----~m-----l--~=-_l:~ ~i/Zr

--------------------%------ ------r------

I I 0.00-0.20 AP I 0.20-0.51 Btl 0.08 I 0.04 1. 33 3.38 2.29 25.63 830 3733 445 8.38 0.51-1.22 Bt2 i 0.04 i 0.01 1.15 2.97 1. 98 23.01 771 3324 438 7.58 1. 22-1. 83 Bw i 2.43 0.87 1.12 1.89 1.50 21.28 708 2982 396 7.53 I

1. 83-2. 29 Bc 0.31 0.07 1.12 1.19 1.61 21.87 626 3099 393 7.88 2.29-2.79 C1 1. 47 0.20 1.08 1.43 1.45 21.18 697 3026 392 7.71 2.79-3.30 2.46 0.85 1.15 1. 62 1.33 19.95 613 2908 452 6.43 3.30-3.81 2.87 0.59 1.00 1.44 1.11 16.73 583 2419 408 5.92 3.81-4.31 2.87 0.83 1.24 2.07 1.37 20.72 697 3072 484 6.3Lf 4.31-4.72 2.14 0.34 1.01 0.75 1.10 18.63 556 2789 438 6.36 4.72-5.33

I

1. 25 0.12 1. 33 1.27 1.53 23.49 782 3495 531 6.56 5.33-5.94 1.41 I 0.38 1.19 1.51 1.47 23.11 598 f

3427 540 6.34 5.94-6.55 3.95 I 1. 74 1. 20 3.02 1. 66 22.20 669 3238 567 5.71 6.55-7.16 3.93 . 1.54 1.29 I 2.91 1.71 23.59 755 3499 602 I 5.81 7.16-7.77 4.32 1. 67 1.23 . 2.82 1. 69 22.69 655 3449 527 '6.54 7.77-8.28

I 4.61 2.00 1.26 I 2.96 1.62 21.94 651 3190 527 6.05 8.28-8.79 2.67 1.07 1. 24 1. 76 1.39 21.21 620 3009 1598 5.03 8.79-9.30 5.45 2.52 1.41 2.82 1.48 22.17 727 3006 478 6.28 9.30-9.80 5.43 I 1.92 1.09 2.28 1.20 19.00 612 2678 490 5.46 9.80-10.21 , 5.74 1.56 1.09 2.34 1.15 18.01 599 I 2399 393 6.10 10.21-10.82 4.19 2.20 1.12 1.67 1.08 19.03 614 I 2656 437 6.07 10.82-11. 43 5.68 Cl.68 1.17 2.70 1.29 18.24 655 • 2555 671 3.80 I 11.43-11.73 C2 1. 60 0.36 1.58 3.52 1.77 25.68 650

13727 714 5.21 11. 73-12.04 0.49 0.03 1.60 4.30 2.06 29.93 503

14565 717 6.36 12.04-12.34 2Btlb 0.06 0.03 1.16 5.15 3.19 26~76 481 4412 746 5.91 12.34-12.65 2Bt2b I 0.08 0.24 1.l~2 4.48 2.62 26.00 432

14272 767 5.56 12.65-12.95 0.25 01.30 1.67 4.73 2.42 29.35 462 4508 749 6.01 12.95-13.26 2Bt3b 0.27 01.25 1.62 4.41 2.24 27.78 569 4236 750 5.64 13.26-13.51 0.30 0.10 1. Lf8 4.03 1.94 27.12 535 4152 804 5.16 I

13.51-13.77 2Bwb 0.11 0.12 1.18 3.22 1.46 23.91 426 i 4523 874 5.17 13.77-13.92 0.12 0.07 1.10 3.93 1. 79 28.41 487 4719 680 6.93

J

t

~

~

\.0

Table 42. (Continued) Whole-soil composition of nine elements and Ti/Zr ratio in a Memphis soil and underlying Paleosols in Vicksburg, Mississippi.

Depth Element lRatio (meters) Horizon Ca I Hg \ K J Al I Fe 1 Si P

----J------bpm----- --~~--l~~ tri/Zr --------------------%--------------------

13.92-14.07 3Bt1b 0.07 0.05 0.90 \ 6.62 3.69 24.43 625 I 1

4379 668 6.55 14.07-14.22 0.06 0.18 1.03 7.63 4.13 25.37 676 I 4602 741 6,,21 14.22-14.38 3Bt2b 0.14 0.02 1.47 6.52 3.15 29.12 566 4762 716 6.65 14.38-14.68 3Bt3b 0.08 0.04 1.50 4.64 2.49 25.66 468 4077 617 6.60 14.68-14.98 3Bt4b 0.05 0.03 1.39 3.88 ' 1.64 I 21.80 349 3358 673 4.98 14.98-15.29 0.07 0.03 11.58 4.37 2.02 24.80 419 1 I ;~~~ 673 5.70 15.29-15.60 0.02 0.02 1.52 4.20 1.81 23.98 443 I 692 5.37 I I 15.60-15.90 0.02 0.02 1.34 3.49 1.38 20.61 404 I 577 5.25 ,

I 3033 15.90-16.20 3cb 0.03

I 0.02 1.64 3.89 1.56 25.05 470 , I 3564 667 5.34

16.20-16.51 0.03 0.03 1.37 3.26 i.07 20.85 494 I ! 2963 674 4.39 16.51-16.81

1 0.02 0.05 I 1.25 3.11 1.36 18.89 662 i 3731 786 4.74 16.81-17.12 4Btb 0.02 0.03 11.07 ' 2.97 1.37 21.89 463 ! 2994 728 4.11

I

I I I I

I i

I ,

I I

I I

I, t ! \ [

I ! !

f-' N a

121

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1970. Particle size sorting of proglacial eolian Soil Sci .. Soc. Amer. Proc. 34:920-924'.

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•

123

.. Handy, R. L. 1976. Loess distribution by variable winds. Geol. Soc. Amer.

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126

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;.

1 tt t/ ,. ..j 1/ P'/1. C;)pt t1 I

lj-- (

TENTATIVE ITINERARY

FRIENDS OF THE PLEISTOCENE FIELD TRIP APRIL 12, 13, 14, 1985

FrIday 12th

1/ C'

7:30-8:00: Assemble at LSU Agricultural Coliseum parking lotpick up guidebooks, etc.

8:00-9:00: Walk about 800-900 feet to southeast down Highland Road to 1st site-remainder of time at site.

9:00-9:30 Drive (southeast) down Highland Road to LSU Avenue (1st light). Turn left on LSU Ave. (LSU becomes Stanford; then Stanford becomes Acad ian). Take 1-10 west off Acadian. Take 1-110 north off 1-10. Take US Highway 61 North off 1-110 (end of 1-110). Site is less than 10 miles north of end of 1-110 on right side of road and is visible from highway.

9:30-10:30: At site.

10:30-11:30: Possible additional site nearby.

11;30-12:00: Return to 1-110 south and to Baton Rouge. Take Government Street exit and turn toward Mississippi River. "0 to "Til Junction at levee and turn left to Catfish Town.

12:00-12;45; Eat lunch at any of :several places in "Catfish Town".

12;115-1;00; Assemble in parking lot of Catfish Tovln.

e

1;00-2:15: Depart: Go back to Government Street. Take 1-110 south exit off Government Street. Then take 1-10 west off 1-110. Continue to Lafayette, lao In lafayette take (167) 1-49 north. Take Carencro exit off 1-49. Go straight across intersection and continue north on access road paralleling 1-49 and passing beside trailer park. Turn right on Highway La. 726. At 1st 90 degree cUrve to right in lao 726 go straight ahead instead

2:15-3:15:

of remaining on La. 726. Stay on this road to 1st side road past where two houses (side by side) ar~ under construction on left. Turn left on that side road. Site is about ~-t mi Ie on left.

At site.

~

3:15-3:45:

3:45-4:45:

4:45-6:00:

6:00 pm:

7:15-7:30;

7:30 am;

8:30-9:30:

9:30-10:00;

Return to north s1de of Lafayette on 1-49. Take Gloria Switch Road east to Moss St. Turn right on Moss St. Take Moss St. to Butcher Switch Road east and turn left on it. Stay on this road to Bayou St. Clair Rd. and turn left on it. Go to "T" Junction and turn right. Drive over 1-10 and take Ches Broussard Road to right. Site is about h\--2 miles on right. (",""'l' b",ck

/V£,-ryl/l'\:, w ~v?<1 At site. J{.A _ "fi-v ~ f: >_

Return to Lafayette, Motels, etc.

Drinks (6:00)-Food (6:30)-Business Meeting (8:00) Yare Build ng in Girard Park In Lafayette, La.

From Interstate 10 take US Highway 167 south to East Unive~sity Ave.; turn left onto East University Ave.; turn right onto West Taft (about 4th street to right); Girard Park will be on your right in about 3 blocks after turning onto West Taft.

Saturday 13th

Assemble in parking lot, La Quinta Motel, lafayette, La.; located on US 167 north and about !-1 mile south of Interstate 10.

Take US 167 (1-49) north. Take US 167 north, turnoff from ,-49. Stay on US 167-the stop will require a left turn off US 167 a short (miles) distance north of the rather obvious e,carpment between the Prairie and Intermediate (Montgomery) Terrace.

At sl teo

US 167 north to next site. This site is a right turn off US 167 just before Meridian Fire Tower. (Lost souls can wait at the tower and see the group return from the site.)

"-0-<.../

10:00-11:00: At site.

11:00-11:45: US 167 north to Alexandria, La. (71 bypass) through Alexandria. turnoff.

Stay on US 167 bypass Take Highway '28 east

11 :45-12:30: Luch at any of several "fast food" places on Highway 28 east.

Note: Some may wish to eat at one of several resaurants along US 71 bypass (McArthur Drive). If so, they can again assemble with the group at the point of departure.

12:30-12:t5: Assemble In Howard's Discount Store parking lot on Highway 28 at east edge of Pineville, La. and across street from McDonald's Restaurant.

12:45-1:45: Depart on Highway 28 east and continue to Highway 84 Junction. Take Highway 84 east (right turn) to Highway 124 (left turn-north to Harrisonburg). Take Highway 124 north to junction with Highway 8. Take Highway ~ east (right turn) to Highway 913 Junction. Turn left on Highway 913. Go to Highway 915; turn left on Highway 915. Site is on a gravel road to left off Highw2Y 915.

1:45-3:00:

3:00-3:30:

3:30-4:30:

4:30-5:30:

("rrJ-r:, IW"i., ~ .' ;-O~i "5 .fyVl<~ (1'n)(9_~) t'P-, ... (

'~·:rHn<?jJ;t.tc~ JI-.. I<'~t: .fli.1J

I 'rt~.;('-~·r ~) P4k.c~TI)€-- b.;/<:cr fb.'cr~1 !o:>o, C\l~vt'J J-..j ~?('f..' ~:7"r(" ~":5S l VI\k; I~~ f:(".r~ t.f.'- ~l JS t.2 ;,4pr"iY'--f

0! h~ >< ", '""4-). Pq /.cu'"'l ':"'':=).-f«''"-I , .... JfhvT\,-W W";'''''.1 hr

i.

7:15-7:30:

7:30-8:45:

8:45-9:30:

At site.

Return to Highway 915 and stay o~ it (it becomes 916) to intersection with Highway 8. Turn left on Highway 8 and drive to intersection with Highway 15. Turn left on Highway 15. Site is on left side on Highway about 7 miles north of Sicily Island, La.

At site.

South on Highway 15 to US 65. Take US 65 south (right turn) to Natchez. Shortly after crossing Mississippi River the lead vehicle will turn right into a shopping center and dri ve past an extens i ve exposure of u,nweathered Peoria loess. Some may wish to stop.

Note: Some may wish to drive a few mi les (less than 10) north of Natchez to view an excellent exposure of a buried Paleosol developed in the Pre-Peoria loess. The exposure is in a road cut for a highway (to be constructed, but not finished). Turn right onto dirt road and drive to t~e 1st deep roadcut on your left. There j.t is. "If' C~~ bL~: (;d-c-titoIA14/;tl. bc;l ......... C ..... lvTl.<Cr

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Sunday 14th

Assemble at Ramada Inn Motel on south side of Highway 84 west and bluff overlooking Mississippi River.

Take Highways 84 and 65 west. Stay on Highway 65 to junction with Highway 15. Turn left onto Highway 15 (15 North). Drive to intersection with Highw~y 130 in Winnsboro, La. Turn left on Highway 130 then right on Highway 618 in about 1 block. Take 618 to junction with Highway 869. Turn right on Highway 869. Drive two miles on Highway 869 and take road to right (in a curve). Site is about 3/4 mile on left.

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1984 Louisiana Loess Fieldtrip Guidebook

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Transcript of 1984 Louisiana Loess Fieldtrip Guidebook