6. MARINE SEDIMENTATION

FACIES & DEPOSITIONAL ENVIRONMENTFACIES & DEPOSITIONAL ENVIRONMENTDefinition

Physical Marine Process•Wave•Tidal Current•Wave Associated Current •Ocean Current Systems•Tides•Storms as Geological Agents•Hurricanes and Tropical Storms •Tsunamis

Marine Facies & Depositional Environment•Coastal Environment & Facies Model•Barrier Environment & Facies Model •Beach Environment & Facies Model•Continental Margine Environment & Facies Model•Deep Marine Environment & Facies Model

Marine Sedimentary Characteristic

FACIES & DEPOSITIONAL ENVIRONMENTFACIES & DEPOSITIONAL ENVIRONMENT

LP

D /

MID

SH

EL

F

LD

F

IS

LD

P

Reef / Bioclastic LimestoneMouth Bar

Distributary Channel Sea Level

UD

P

Lit

oral

U

DF

Sub

Aer

ial

Shor

elin

e

UP

D

LEGENDA

LDP : Lower Delta Plain

UDP : Upper Delta Plain

UDF / Lit : Upper Delta Front

LDF / IS : Lower Delta Front / Litoral

UPD /IS : Upper Prodelta / Inner Shelf

CS / R : Carbonate Shelf / Reef

SA : Sub Aerial

LPD /MS : Lower Prodelta / MId Shelf

Physical Marine Process

Wave shoaling and breaking. As deep-water waves are transformed by interaction with the bottom, the wave length is reduced and height increased

until they reach a maximum peak. The wave then collapse in the form of breakers, whih are classed as surging, spiling or plunging

WAVE PROCESS


Wave Associated Current

Davis 1964 classified the world's shorelines as either microtidal (tidal range = 0-2m); mesotidal (tidal range = 2-4m) or macrotidal (tidal range greater than 4m).

Worldwide distribution of coastal tidal ranges

TIDES

Ocean Current Systems


Major ocean current and climate zones


Hurricanes and Tropical StormsWestward moving tropical waves are best known for the "low" part of the surface pressure cycle. Tropical lows generally exhibit variable weaker winds and increased cloudiness and precipitation. Wave conditions under a tropical low are usually calmer on the average, except near centers of strong precipitation, which are accompanied by strong winds (and large seas) of short duration.

Coastal erosion from Hurricane surge and waves

Tsunamis are much less frequent than hurricanes, but the size and power of the wave forces is devastating (Wave Spectra). Faulting (earthquakes), massive submarine slope failure and volcanic activity can generate a tsunami that can propogate over an entire ocean basin.

These are essentially high speed tidal waves that are modified in deep water because of the extreme wave length. The high wave crest breaking and falling onshore can create major damage and modify sediment patterns.


Spectrum of wave energy in the ocean

BARRIER ENVIRONMENTThe major sedimentary environments of a barrier island consists of: •The mainland, •Backbarrier lagoon, •Barrier island, •Inlets and inlet deltas, •Barrier platform, and •The shoreface

MARINE DEPOSITIONAL ENVIRONMENT & FACIES MODEL


COASTAL ENVIRONMENT

Fig 34 .Fig 34 .


BARRIER FACIES MODEL

Three “end-member” facies successions associated with regressive and transgressive barrier island, and inlet migration. After Reinson (1984)

Generalized lagoonal sequence through back barrier deposits in the Carboniferous of eastern Kentucky and southern West Virginia. Such sequences range from 7.5 to 24 m thick. From Horne and ferm (1978)

MARINE DEPOSITIONAL ENVIRONMENT& FACIES MODEL

LAGOON FACIES MODEL

Tidal channel-fill sequences for an inlet channel located along an active barrier-island. After Moslow an Tye (1985)


Tidal ChannelFACIES MODEL

The beach has three major parts: beach face, berm and backbeach


The beach consist of a shorface, nearshore zone, and dune associated with a beach. Not all of these element are present in many beaches.

BEACH ENVIRONMENT

SHORELINE-SHALLOW MARINE PROFILE

2

CruzianaZoophycos

Skolithos

MUDDY SUBSTRATE SANDY SUBSTRATE

LOWER MIDDLE UPPER

WAVES BEGIN TO BUILD UP

SHOALING WAVES

SPILLING BREAKERS

SURF ZONE LOW

HIGH TIDE

Ichnofacies

LONGSHORE BARS

SHOREFACE

OFFSHORE

FORESHORE

STORM WAVE BASE

FAIRWEATHER WAVE BASE

VERTICAL SCALE GREATLY EXAGGERATED

L

5 –15 ML

CruzianaZoophycos

Skolithos

MUDDY SUBSTRATE SANDY SUBSTRATE

LOWER MIDDLE UPPER

WAVES BEGIN TO BUILD UP

SHOALING WAVES

SPILLING BREAKERS

SURF ZONE LOW

HIGH TIDE

Ichnofacies

LONGSHORE BARS

SHOREFACE

OFFSHORE

FORESHORE

STORM WAVE BASE

FAIRWEATHER WAVE BASE

VERTICAL SCALE GREATLY EXAGGERATED

L

5 –15 ML2

RUNNEL SYSTEM IN THE BEACH ENVIRONMENT


BEACH FACIES MODEL

Generalized cross section of continental margin shows deep basin, buried beneath the shelf and slope, which is filled with sediments. A buried reef mark an old shelf edge.

Consists Of: continental rise continental slope continental shelf


BEACH ENVIRONMENT

Vertical sequences produced through transgression of different types of coastal environments. Modified from Demarest and Kraft (1987)

CONTINENTAL SHELFFACIES MODEL



DEEP MARINE ENVIRONMENTSubmarine canyons are common along the continental slope. They are ubiquitous on both active and passive margins. Some extend landward across the continental shelf. They typically cut through the edge of the continental shelf and terminate on the deep abyssal floor, some 5,000 or more feet below sea level.

Turbidity currents intermittently flush sediments through the canyons building up depositional fans where the currents reach the lower gradient of the ocean floor.

The abyssal plain is the deep ocean floor. It is basically flat, and is covered by very fine-grained sediment, consisting primarily of clay and the shells of microscopic organisms (such as foraminifera, radiolarians, and diatoms).

Generalized three-dimension is showing submarine canyon and deep sea environment

Stratigraphic section of deep marine facies, showing basin floor, channels and levee deposits.


DEEP MARINE ENVIRONMENT

MARINE SEDIMENTARY ENVIRONMENT

REEFCONTINENTAL

SHELFCONTINENTAL SLOPE

AND RISEABYSSAL PLAIN

Rock TypeFossiliferous

limestone

Sandstone, shale, siltstone,

fossiliferous limestone, oolitic

limestone

Litharenite, siltstone, and shale (or

limestone)

Shale, chert, micrite, chalk, diatomite

Composition CarbonateTerrigenous or

carbonateTerrigenous or

carbonateTerrigenous or

carbonate

Color Gray to white Gray to brown Gray, green, brown Black, white red

Grain SizeVariable,

frameworks, few to no grains

Clay to sand Clay to sand Clay

Grain Shape --- --- --- ---

Sorting --- Poor to good Poor Good

Inorganic Sedimentary Structures

---Lamination, cross-

bedding

Graded bedding, cross-bedding, lamination,

flute marks, tool marks (turbidites)

Lamination

Organic or Biogenic Sedimentary Structures

--- Trails, burrows Trails, burrows Trails, burrows

FossilsCorals, marine

shellsMarine shells

Marine shells, rare plant fragments

Marine shells (mostly microscopic)

SEA WATER COMPOSITION

TRANSITIONAL SEDIMENTARY ENVIRONMENT BARRIER BEACH LAGOON TIDAL FLAT

Rock TypeQuartz arenite,

coquina

Siltstone, shale, limestone, oolitic

limestone or gypsum

Siltstone, shale, calcilutite, dolostone

or gypsum

Composition Terrigenous or

carbonate

Terrigenous, carbonate, or

evaporite

Terrigenous, carbonate, or

evaporite

Color White to tan Dark gray to black Gray, brown, tan

Grain Size Sand Clay to silt Clay to silt

Grain Shape Rounded to angular --- ---

Sorting Good Poor Variable

Inorganic Sedimentary Structures

Cross-bedding, symmetrical ripples

Lamination, ripples, cross-bedding

Lamination, mudcracks, ripples,

cross-bedding

Organic or Biogenic Sedimentary Structures

Tracks, trails, burrows Trails, burrowsStromatolites, trails,

tracks, burrows

Fossils Marine shells Marine shells Marine shells

MINERAL OF MARINE DEPOSITMINERAL OF MARINE DEPOSIT

FUNDAMENTAL DEFINITIONS

A "mineral occurrence" is a concentration of a mineral (usually, but not necessarily, considered in terms of some commodity, such as copper, barite or gold) that is considered valuable by someone somewhere, or that is of scientific or technical interest. In rare instances (such as titanium in a rutile-bearing black sand), the commodity might not even be concentrated above its average crustal abundance.

A "mineral deposit" is a mineral occurrence of sufficient size and grade that it might, under the most favorable of circumstances, be considered to have economic potential.

SAMPLE OF MARINE DEPOSIT MINERALS

Glauconite(K,Na)(Al,Fe3+,Mg)2(Al,Si)4O10(OH)2System. Monoclinic.

Appearance. Very tiny crystals. Usually in spherulitic, earthy aggregates, sometimes platy, light blue-greenPhysical properties. Soft (2-2.5), light, perfect basal cleavage. Transculent with rather greasy luster.

Environment. A mineral of marine origin, found in sedimentary deposits of various kinds (sands, sandstones, silts, impure limestones), probably as a diagenetic mineral.

Sulfur - SSystem. Orthorhombic.

Appearance. Frequently in fine, dipyramidal crystals, granular aggregates, impregnations and incrustations. Color varies from the characteristic lemon-yellow, when the mineral is pure, to brown and black.

Physical properties. Very soft to soft (1.5-2.5), very light, fragile, with poor cleavage. Transparent to translucent with resinous to greasy luster.

Environment. A mineral associated with sedimentary deposits of the evaporite type and with oil-bearing deposits. Believed to be a product of the dissociation of sulfates (especially gypsum) caused by the action of certain bacteria.


Siderite – FeCO3

System. Hexagonal.

Appearance. Rhombohedral crystals with curved, striated faces. Sometimes with tabular habit and in saddle-shaped aggregates. Botryoidal, compact, oolitic, concretionary masses common, varying in color from pale yellow to dark brown or almost black when a large amount of manganese is present.

Physical properties. Semi-hard (3.5-4), heavy, fragile, perfect rhombohedral cleavage. Transparent or translucent with bright vitreous luster. White streak. Alters readily on the surface, becoming coated by brown goethite. Practically infusible. Decomposes at a moderate temperature, turning brown and becoming magnetic.

Environment. Formed in environment of continental waters with low oxygen content, associated with clay and carbonaceous material.


Pyrite - FeS2

System. IsometricAppearance. Striated, cubic, octahedral or pyritohedral crystals, sometimes occuring as “iron cross” twins. Compact, granular aggregates. Concretions, mammilated and stalactitic nodules. Always fairly dark yellow, sometimes with an iridescent yellowish-brown film.

Physical properties. Hard (6-6.5), very heavy, very fragile, with poor cleavage. Opaque with very bright metallic luster. Greenish-black streak.

Environment. Pyritized concretionsformed by chemical deposition under the water.


Halite – NaCl

System. Isometric.Appearance. Cubic crystals, sometimes distorted with cavernous faces, “hopper” crystals. Colorless to white, yellow, red, brown, and even black.

Physical properties. Soft (2.5), very light, fragile with perfect cubic cleavage. Transparent to translucent with vitreous luster. White streak.

Environment. As a precipitate in sedimentary deposit caused by the evaporation of saline water. Often interbedded with clay.


Fluorite - CaF2

System. Isometric.Appearance. Cubes, octahedrons, and dodecahedrons, other forms rarer. May be large. Penetration twins sometimes occur. Color extremely variable (allochromatic), colorless and completely transparent when pure, but may be yellow, green, blue, pink, purple, or even black. Campact, banded and concretionary masses are frequently found.

Physical properties. Semi hard (4), heavy, fragile, perfect octahedral cleavage. Transparent to translucent with vitreous luster.

Environment. In sedimentary origin probably by deposition in enclosed basins from saline waters possibly of volcanic origin.


Magnetite - Fe2+Fe3+2O4

System. Isometric

Appearance. Black, shiny, perfect octahedrons or dodecahedrons with striated faces . Iron-black, campact and granular masses with bluish iridecence.

Physical properties. Hard (5.5-6.5), very heavy, no cleavage, but exhibits octahedral parting. Opaque with metallic luster. Black streak. Strongly magnetic and sometimes act as a natural magnet (Iodostone).

Environment. Large masses found in sedimentary rocks (alluvial and marine sands).


Hematite - Fe2O3

System. Hexagonal.Appearance. Stubby, black, rhombohedral crystals, often with individual crystal arranged like the petals of rose. More commonly in massive, granular masses, compact, sometimens with iridescence surface, soft and earthy. Often oolitic, botryoidal or concretionary in appearance. Often colors both rocks and minerals shade of red and reddish brown.

Physical properties. Hard (5.5-6.5), very heavy, fragile, no cleavage.

Opaque with metallic luster, blood red tints in thin section. Streak dark-cherry red.

Environment. Formed under sedimentray conditions through diagenesis of “limonite” retaining its concretionary and oolitic foems.


Ilmenite - FeTiO3

System. Hexagonal.Appearance. Very flat, taabular, black or dark brown, rhombohedral crystals. Also in compact or granular aggregates.

Physical properties. Hard (5-6), heavy, no cleavage, but fairly good pseudo-rhombohedral fracture. Opaque, even in thin section, with sub metallic luster. Black to brownish red streak.

Environment. Large concentration found in marine sand.


LimoniteAppearance. Generally occurs as botyoidal, stalactitic, oolitic, or pisolitic, colloform, earthy or porous masses, or in the form of a crust, yellowish broen when loose, blackish and iridencence when more coherent.

Physical properties. Very varied, depending on the constituent or the type of aggregations. Frequently semi hard (5-5.5), and fragile, disintegrates easily. Transcullent with semi opaque with vitreous to earthy luster. Pale-brown streak.

Environment. Form in the littoral zones of marine basins as a result of the flocculation of iron hydroxides caused by electrolytic or bacterial action


Calcite - CaCO3

System. Hexagonal.Appearance. Rhombohedral, scalenohedral or prismatic crystals, often intergrown or twinned. Variable color (colorless, white, pink, green, yellow, etc.). Occurs in masses, compact, microcrystalline (limestones), saccharoidal (marbles), fibrous (alabasters), concretionary (stalactites and stalagmites), pulverulent, oolitic, etc.

Physical properties. Semi hard (3), light, with perfect rhombohedral cleavage. Transparet with vitreous or iridescent pearly luster depending on direction, transculent or opaque. White streak

Environment. Typical sedimentary mineral formed by chemical precipitation through the evaporation of solutions rich in calcium bicarbonate or by extraction through the action of marine organisms


Dolomite - CaMg(CO3)2

System. Hexagonal.Appearance. Usually in colorless, white, pink, or yellowish rhombohedral crystals. Aggregates of crystals with curved “saddle” faces frequent. Compact, saccharoidal, sometimes dolomite masses.

Physical properties. Semi-hard (3.5-4), not very heavy, fragile, perfect rhombohedral cleavage. Transparent or translucent with vitreous or sometimes pearly luster. White streak.

Environment. Basic constituent of sedimentary carbonate rocks formed under diagenetic conditions by the action of sea water on calcareous mud or by organogenetic formation


Aragonite - CaCO3

System. Orthorombic.Appearance. Small, elongated, prismatic crystals. Concretionary, pisolitic, stalactitic, fibrous and radiating, or corraloid masses. Colorless, white, yellow, reddish, and various other colors.

Physical properties. Semi-hard (3.5-4), heavy, fragile, indistinct prismatic cleavage. Transparent or translucent with vitreous luster. White streak.

Environment. Formed easily in sedimentary environmet, under metastable conditions, helped by biological action


Gypsum - CaSO4.2H2O

System. Monoclinic.Appearance. Clear, tabular crystals often in swallowtail or spearhead twins. Transparent crystals and cleavage fragments. Fibrous aggregates of elongated satiny crystals. Granular and compact, waxy-looking masses, sometimes banded. White, gray, yellowish or brown.

Physical properties. Soft (2) and light. Perfect cleavage into slightly flexible but inelastic plates and very find flakes. Transparent, with vitreous or silky luster, often pearly on cleavage faces.

Environment. A typical sedimentary evaporite minerals, formed through direct precipitation from saline waters or through alteration of anhydrite


Biotite - K(MgFe)3(Al,Fe)Si3O10(OH,F)2System. Monoclinic.

Appearance. Rarely in tabular pseudo-hexagonal crystals, black, brown or dark green. Commonly in small disseminated plates or platy aggregates.

Physical properties. Soft (2.5-3), heavy, perfect basal cleavage into small, flexible, elastic, transparent or translucent, brownish sheets, with very pronounced vitreous luster.

Environment. Widespread as a sedimentary mineral in sand and sandstones


Quartz - α-SiO2System. Hexagonal.

Appearance. May occur in well-formed crystal, compact oand concretionary masses, microcrystalline to cryptocrystalline. Colorless when pure.

Physical properties. Very hard (7), and light. No cleavage, but good conchoidal fracture. Transparent with translucent with vitreous luster.

Environment. Stable in sedimentary conditions either as a detrital mineral or as a cement in consolidated rocks (sandstones)


6. MARINE SEDIMENTATION

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