6 Stop 7 ~4 mi · and impure quartzite (156 to 158 Ma, Ar/Ar amphibole, Yule, 1996; Yule et al.,,...
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1 Chetco River Illinois River Rogue River ChP VP CaP WB PP EDM SM OM Illinois River Hwy 199 Selma Oak Flats Selma JTrvs JTrvs JTvs JTrvs JTrvs JTrvs JTrvs JTrvs Jf Jf Jf JTrvs JTrvs JTrvs JTrvs JTrvs JTrvs JTrvs JTrvs JTrvs area not mapped Jp Jp Jp Jp Jp Jp Jp Jg Jg Jg Jg Jg Jg Jr Jr Jr Jr Jg Jg Jr Jr Jg Jg Jg Jb Jb area not mapped Jr Jr Jg area not mapped Jg Jr Jr Jj Jj Jj Jj Jj Jj Jj Jp Jp Jj Jp Jp Jp Jog Jgd Jt Jt Jt Jfl Jp Jt Jr Jr Jr Jm Jm Jm Jr Jr Jr Jm Ja Ja Jd Ja Jp Jp Ja Jr Jfl Jfl Jp Jt Jgd JTrvs Jr Jgd Ja Jm Galice Onion Mtn. Chrome Ridge York Butte Pearsoll Peak Eight Dollar Mtn. Cave Jct. Josephine Mtn. Chetco Peak Biscuit Hill Selma Mt. Peavine USGS 7.5' topographic map coverage of study area Buckskin Pk. Location Map Index to geologic mapping 1.Yule, 1996 2. Ramp, 1986 3. Ramp, 1984 4. Loney & Himmelburg, 1977 5. Dick, 1976 6. Ramp, 1975 1 2 3 4 5 6 Other sources Irwin, 1994; Page et al., 1981; Ramp, 1977; Ramp and Peterson, 1979; Smith et al., 1982; Wells et al., 1948; Wells and Walker, 1953; Wise, 1969 5 5 10 MILES 0 5 5 10 KILOMETERS 0 20 TRUE NORTH MAG. NORTH Explanation of Geologic Map and Cross Section Q JTp Jfm JTrvs Jh Jh Jm Jr Jr Jm Ja Ja Jr Jr Jr Jj Q Q Q Q Q Q LATE MIDDLE AND LATE JURASSIC PRE-MIDDLE JURASSIC TRIASSIC (?) AND JURASSIC QUATERNARY SURFICIAL DEPOSITS Jg INTER-ARC BASIN VOLCANIC AND SEDIMENTARY ROCKS Jr Jj Jp JOSEPHINE OPHIOLITE ONION CAMP COMPLEX CHETCTO PLUTONIC COMPLEX CROSS-STITCHING PLUTONIC ROCKS LATE JURASSIC Jf mafic to intermediate hornblende-phyric dikes and small intrustions; U-Pb, K-Ar, and Ar-Ar ages cluster at ca. 150 Ma (Yule, 1996; Dick, 1976; and Harper et al., 1994). Jh JTrvs Jp JTrvs X X' METAMORPHIC WALLROCKS Jt Jgd Jog Ja Jb Jm SYMBOLS Contact, dashed where approximately located Fault, dashed where approximately located Thrust fault, dashed where approximately located, sawteeth on upper plate Drainage Unconsolidated silt, sand, and gravel deposits occupying modern stream and river channels, and associated low terraces and flood plains. Rogue Formation; massive to well-bedded, basaltic to andesitic volcanogenic turbidites, volcanic breccias, and flows; 157 Ma (U-Pb zircon, Saleeby, 1984), 153 Ma (Ar/Ar hornblende,Yule, 1996). Galice Formation; basal hemipelagic section of Callovian age overlain by flysch sequence of Oxfordian- Kimmeridgian age (Pessango and Blome, 1990). Fiddler Mountain olistostrome; polymictic conglomerate, breccia, and megabreccia - ophiolite clast-types dominate, with subordinate chert and serpentine clast-types - interlayered with well-bedded sequences of chert and argillite (thin dashed lines near Fiddler Mtn. (FM)). Chert yields poorly preserved Late Jurassic (Kimmeridgian?) radiolaria (Yule et al. , 1992, 2006). weakly foliated tonalite-trondhjemite sill-like complex occupying high structural levels of plutonic complex (157 Ma, U-Pb zircon, Yule, 1996). Jfl main phase, foliated to massive biotite hornblende quartz diorite, hornblende gabbro-diorite, and norite (160 Ma, U-Pb zircon, Yule, 1996). layered olivine gabbro and two-pyroxene gabbro forming the core of the plutonic complex. marginal facies consisting of flaser quartz diorite, diorite, and gabbro with shallowly plunging lineations and steeply dipping foliations. cumulate gabbro, massive gabbro, sheeted mafic dikes, and pillow lavas and lava breccias, interpreted as age equivalent with the Josephine ophiolite of Harper (1984). (162-166 Ma, U- Pb, zircon, Saleeby, 1984). variably serpentinized tectonized harzburgite and dunite, interpreted as mantle lithosphere equivalent of Josephine ophiolite (Dick, 1976; Harper, 1984). Briggs Creek amphibolite (e.g., Coleman and Lanphere, 1991); amphibolite gneiss, schist, and impure quartzite (156 to 158 Ma, Ar/Ar amphibole, Yule, 1996; Yule et al.,, 2006). amphibolite and amphibolite gneiss, biotite-hornblende schist, impure quartzite and metagabbro found in metamorphic sole of Madstone Cabin thrust (148 to 153 Ma, Ar/Ar muscovite and hornblende, and U-Pb zircon, Harper et al., 1994). complexly folded outcrop belts of amphibolite and amphibolite gneiss, biotite-hornblende schist, and impure quartzite transitional to greenschist facies metavolcanic and metasedimentary rocks of complex, most common near Squaw Mtn (SM; 170 to 173 Ma, Ar/Ar hornblende, Yule 1996; Yule et al., 2006). heterogeneous mafic intrusive complex, consisting of diabase, gabbro, and sheeted mafic dikes. most extensive outcrop belts occur in areas near Whetstone Butte (WB), with local, smaller belts (not shown) occur throughout the metavolcanic and metasedimentary sequence (JTrvs). age unknown, but may be broadly correlative with Josephine ophiolite gabbro, mafic dikes. highly serpentinized and sheared dunite, harzburgite, and sparse websterite; cut by numerous intermediate to mafic dikes, and occasional rodingite dikes; plagiogranite dikes yield U-Pb zircon ages of 173 and 175 Ma (Yule, 1996; Yule et al., 2006). greeschist facies metavolcanic and metasedimentary rocks, including massive greenstone, pillow lava, tuff and tuff-breccia, argillite and red chert; chert samples yield mostly amorphous radiolaria with scarce Triassic (?) and Jurassic forms (Yule et al., 1992, 2006; C. Blome, personal communication, 1992). Axis of regional-scale, overturned synclinal folds Jr FM Jp Jog Jgd Jgd Jt Jt Jfl Jp Jb Jp Jp Jr Jr Jr Jr Jg Jg Jg Jj Jm Jm Jp Jp Jj Jp JTrvs JTrvs JTrvs Jf Jg JTrvs 5000' -5000' s. l. 5000' -5000' s. l. Jp X X' NW SE 1 2 3 4 5 6 Stop 7 42˚15¨ 42˚30¨ 124˚ 123˚45¨ ~4 mi 8 Hwy 199 USFS roads, field trip routes 3 Field trip stop Figure 3. Geologic map, cross section along X–X′, and explanation of part of the western Jurassic belt, Klamath Mountains, Oregon (modified after Yule et al., 2006, their figure 2). Bold-faced numbers 1–8 refer to locations of Day 2 field trip stops. CaP—Canyon Peak, ChP—Chetco Peak, EDM—Eight Dollar Moun- tain, FM—Fiddler Mountain, OM—Onion Mountain, PP—Pearsoll Peak, SM—Squaw Mountain, WB—Whetstone Butte, VP—Vulcan Peak.
Transcript of 6 Stop 7 ~4 mi · and impure quartzite (156 to 158 Ma, Ar/Ar amphibole, Yule, 1996; Yule et al.,,...
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Chetco River
Illinois River
Rogue River
ChP
VP
CaP
WB
PP
EDM
SM
OM
Illinois River
Hwy 199
Selma
Oak Flats
Selma
JTrvs
JTrvs
JTvs
JTrvs
JTrvs
JTrvs
JTrvs
JTrvs
Jf
Jf
Jf
JTrvs
JTrvs JTrvs
JTrvs
JTrvs
JTrvs
JTrvs
JTrvs
JTrvs
area not m
apped
Jp
Jp
Jp
Jp
Jp
Jp
Jp
Jg
Jg
Jg
Jg
Jg
Jg
Jr
Jr
Jr
Jr
Jg
Jg
JrJr
Jg
Jg
Jg
Jb
Jb
area not m
apped
Jr
Jr
Jg
area not mapped
Jg
Jr
Jr
Jj
Jj
Jj
Jj
Jj
Jj
Jj
Jp
JpJj
Jp
Jp
Jp
Jog
Jgd Jt
Jt Jt
Jfl
Jp
Jt
Jr
Jr
Jr
Jm
Jm
Jm Jr
Jr
Jr
Jm
Ja
Ja
Jd
Ja Jp
Jp
JaJr
Jfl
Jfl
Jp
Jt
Jgd
JTrvs
Jr
Jgd
Ja
Jm
Galice
OnionMtn.Chrome
RidgeYork Butte
PearsollPeak
EightDollarMtn.
Cave Jct.Josephine
Mtn.ChetcoPeak
Biscuit Hill
Selma
Mt. Peavine
USGS 7.5' topographicmap coverage of study area
Buckskin Pk.
Location Map
Index to geologic mapping
1.Yule, 19962. Ramp, 19863. Ramp, 19844. Loney & Himmelburg, 19775. Dick, 19766. Ramp, 1975
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2
3
45
6
Other sourcesIrwin, 1994; Page et al., 1981; Ramp, 1977; Ramp and Peterson, 1979; Smith et al., 1982; Wells et al., 1948; Wells and Walker, 1953; Wise, 1969
5 5 10 MILES0
5 5 10 KILOMETERS0
20
TRU
E N
OR
TH
MA
G. N
ORT
H
Explanation of Geologic Map and Cross Section
Q
JTp
Jfm
JTrvs
Jh
Jh
Jm
Jr
Jr
Jm
Ja
Ja
Jr
Jr
Jr
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Q
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Q
LATE
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DLE
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ATE
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IDD
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TRIA
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ASS
IC
QU
ATER
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SURFICIAL DEPOSITS
Jg
INTER-ARC BASIN VOLCANIC AND SEDIMENTARY ROCKS
Jr
Jj
Jp
JOSEPHINE OPHIOLITE
ONION CAMP COMPLEX
CHETCTO PLUTONIC COMPLEX
CROSS-STITCHING PLUTONIC ROCKS
LATE
JU
RA
SSIC
Jf
mafic to intermediate hornblende-phyric dikes and small intrustions; U-Pb, K-Ar, and Ar-Ar ages cluster at ca. 150 Ma (Yule, 1996; Dick, 1976; and Harper et al., 1994).
Jh
JTrvs
Jp
JTrvs
X
X'
METAMORPHIC WALLROCKS
Jt
Jgd
Jog
Ja
Jb
Jm
SYMBOLS
Contact, dashed where approximately located
Fault, dashed where approximately located
Thrust fault, dashed where approximately located,sawteeth on upper plate
Drainage
Unconsolidated silt, sand, and gravel depositsoccupying modern stream and river channels, and associated low terraces and flood plains.
Rogue Formation; massive to well-bedded, basaltic to andesitic volcanogenic turbidites, volcanic breccias, and flows; 157 Ma (U-Pb zircon, Saleeby, 1984), 153 Ma (Ar/Ar hornblende,Yule, 1996).
Galice Formation; basal hemipelagic section of Callovian age overlain by flysch sequence of Oxfordian-Kimmeridgian age (Pessango and Blome, 1990).
Fiddler Mountain olistostrome; polymictic conglomerate, breccia, and megabreccia - ophiolite clast-types dominate, with subordinate chert and serpentine clast-types - interlayered with well-bedded sequences of chert and argillite (thin dashed lines near Fiddler Mtn. (FM)). Chert yields poorly preserved Late Jurassic (Kimmeridgian?) radiolaria (Yule et al. , 1992, 2006).
weakly foliated tonalite-trondhjemite sill-like complex occupying high structural levels of plutonic complex (157 Ma, U-Pb zircon, Yule, 1996).
Jfl
main phase, foliated to massive biotite hornblende quartz diorite, hornblende gabbro-diorite, and norite (160 Ma, U-Pb zircon, Yule, 1996).
layered olivine gabbro and two-pyroxene gabbro forming the core of the plutonic complex.
marginal facies consisting of flaser quartz diorite,diorite, and gabbro with shallowly plunging lineations and steeply dipping foliations.
cumulate gabbro, massive gabbro, sheeted mafic dikes, and pillow lavas and lava breccias, interpreted as age equivalentwith the Josephine ophiolite of Harper (1984). (162-166 Ma, U-Pb, zircon, Saleeby, 1984).
variably serpentinized tectonized harzburgite and dunite, interpreted as mantle lithosphere equivalent of Josephine ophiolite (Dick, 1976; Harper, 1984).
Briggs Creek amphibolite (e.g., Coleman and Lanphere, 1991); amphibolite gneiss, schist, and impure quartzite (156 to 158 Ma, Ar/Ar amphibole, Yule, 1996; Yule et al.,, 2006).
amphibolite and amphibolite gneiss, biotite-hornblende schist, impure quartzite and metagabbro found in metamorphic sole of Madstone Cabin thrust (148 to 153 Ma, Ar/Ar muscovite and hornblende, and U-Pb zircon, Harper et al., 1994).
complexly folded outcrop belts of amphibolite and amphibolite gneiss, biotite-hornblende schist, and impure quartzite transitional to greenschist facies metavolcanic and metasedimentary rocks of complex, most common near Squaw Mtn (SM; 170 to 173 Ma, Ar/Ar hornblende, Yule 1996; Yule et al., 2006).
heterogeneous mafic intrusive complex, consisting of diabase, gabbro, and sheeted mafic dikes. most extensive outcrop belts occur in areas near Whetstone Butte (WB), with local, smaller belts (not shown) occur throughout the metavolcanic and metasedimentary sequence (JTrvs). age unknown, but may be broadly correlative with Josephine ophiolite gabbro, mafic dikes.
highly serpentinized and sheared dunite, harzburgite, and sparse websterite; cut by numerous intermediate to mafic dikes, and occasional rodingite dikes; plagiogranite dikes yield U-Pb zircon ages of 173 and 175 Ma (Yule, 1996; Yule et al., 2006).
greeschist facies metavolcanic and metasedimentary rocks, including massive greenstone, pillow lava, tuff and tuff-breccia, argillite and red chert; chert samples yield mostly amorphous radiolaria with scarce Triassic (?) and Jurassic forms (Yule et al., 1992, 2006; C. Blome, personal communication, 1992).
Axis of regional-scale, overturned synclinal folds
Jr
FM
Jp
Jog
Jgd
Jgd
JtJt
JflJp
Jb
JpJp
JrJr
Jr
Jr
Jg Jg
Jg
Jj
Jm
Jm
Jp Jp Jj
Jp
JTrvs
JTrvs
JTrvs
JfJg
JTrvs
5000'
-5000'
s. l.
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-5000'
s. l.
Jp
X X'
NW SE
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23
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6Stop 7
42˚15¨
42˚30¨
124˚
123˚
45¨
~4 mi
8
Hwy 199
USFS roads, field trip routes
3 Field trip stop
Figure 3. Geologic map, cross section along X–X′, and explanation of part of the western Jurassic belt, Klamath Mountains, Oregon (modified after Yule et al., 2006, their figure 2). Bold-faced numbers 1–8 refer to locations of Day 2 field trip stops. CaP—Canyon Peak, ChP—Chetco Peak, EDM—Eight Dollar Moun-tain, FM—Fiddler Mountain, OM—Onion Mountain, PP—Pearsoll Peak, SM—Squaw Mountain, WB—Whetstone Butte, VP—Vulcan Peak.
