sedimentary basins & their sedimentation pattern

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Sedimentary Basins & theirSedimentation Pattern

Rajesh Singh ShekhawatMSc (Prev.) 2011

Under the guidance ofProfessor D. K. Pandey


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Sedimentary basins are regions of prolongedsubsidence of Earth's surface.

Driving Mechanisms Plate Tectonics, &

other tectonic and Dynamic activities - resultin isostatic adjustments, loading & unloading.

Earth's crust About 20 rigid plates, whose

movement result in Divergence,Convergence, & Strike-slip Basin formation.

INTRODUCTION


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Major & Minor Plates of Earths Lithosphere


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Tectonic Elements of Earth


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Factors affecting depositional processes & resulting sedimentary facies


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5.Suturing

1. RiftBasin

2. Proto-Ocean &Ocean Basin

3. Arc-Trench Formation4. Ocean Closure

Wilson Cycle


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Many classifications given. In general, the basis of classification are

Type of Crust on which the basins rest,

Position of basin with respect to plate margins,

Type of plate interactions during sedimentation for basinslying close to a plate margin.

Classification of SedimentaryBasins


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Most Comprehensive Basin Classification by Busby &Ingersoll (1995)

Divergent Settings

Terrestrial rift

valleys

Rifts within continental crust commonly

associated with bimodal volcanism. Ex

Rio Grand rift (New Mexico)

Proto-oceanicrift troughs Incipient oceanic basins floored by newoceanic crust & flanked by young rifted

continental margins. ExRed Sea


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Intraplate SettingsPassive

Margin basin

Mature rifted continental margins in intraplate

settings at OC interfaces. ExEast Coast of USA

Continental

embankmen

ts

Progradational sediment wedges constructed off

edges of rifted continental margins. Ex

Mississippi Gulf CoastIntracratonic

basins

Broad cratonic basins floored by fossil rifts in

axial zones. ExChad Basin (Africa)Continental

platforms

Stable cratons covered with thin & laterally

extensive sedimentary strata. Ex Barents Sea

(Asia)Active ocean

basins

At divergent plate boundaries (spreading still

active). Ex Pacific Ocean

Oceanic Is,

aseismic

ridges,

Sedimentary aprons & platforms; In intraoceanic

settings other than magmatic arcs. ExEmperor-

Hawaii seamounts


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Convergent settingsTrenches Deep troughs; By subduction of oceanic lithosphere.

ExChile TrenchTrench-slope

basins

Local depressions upper part of Trenches. ExCentral

America TrenchForearc basins Within arc-trench gaps. ExSumatraIntraarc basins Along arc platform. ExLago de NicaraguaBackarc basins Oceanic behind intraoceanic magmatic arcs(O-O). Ex

Marianas.

Continental behind continental-margin magmatic arcswithout foreland fold-thrust belts(C-C). ExJapan Sea.

Retroarc

foreland basins

Foreland basins on subducting plate in C-C/C-O formed

by subduction-generated compression &/or collision).

ExAndes foothillsRemnant ocean

basins

Shrinking ocean basins caught b/w colliding continental

margins &/or arc-trench systems. ExBay of Bengal

Peripheral

foreland basins

Foreland basins above subducted continental margins

during C-C collisions. ExPersian Gulf


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Hybrid settingsIntracontinental wrenchbasins

Diverse basins form due to distant collisionalprocesses. ExQaidam Basin (China).

Aulacogens Failed rifts at high angles to continental margins.ExNorth Sea.

Impactogens Rifts at high angles to orogenic belts, without

preorogenic history (in contrast with aulacogens).ExBaikal rift (Siberia).

Successor

basins

Form in intermontane settings following cessationof local orogenic activity. ExS. Basin & Range

Transform/Strike-Slip settingsTranstensio

nal

By extension along strike-slip fault systems. Ex

Salton Sea.Transpressional

By compression. ExSanta Barbara Basin.

Transrotational

By rotation of crustal blocks about vertical axes. ExWestern Aleutian.

Overstep B/W ends of 2 sub-parallel strike-slip fault segments.Ex Dead Sea Basin


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Strike-Slip Basins

Form in a wide variety of geodynamical settings;Varied structural history, active seismicity & low heat

flow.High Subsidence & Sedimentatiion rates.Relatively narrow, high syndepositional relief .

Sedimentary Fill Rapid lateral facies changes

Marginal Fans(breccias, Conglmerates) tight up againstthe fault;

Axial lacustrine facies mud, shale;Streamflow-dominated fans(fluviatile sandstone &

conglomerate) along opposite margin;


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Best known intracontinentaltransform San Andreas system,

& 1 of the best documented pullapart basins in this system Ridge Basin, California.

Strike-Slip Basins Continued.


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Basins in Convergent Setting

Compressive regime inhomogeneous stressdistribution & thermal effects produces both,Extensional & Compressional Basins.


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Backarc Basin

Extensional;

Typically underfilled, containing mainly deep-watersediment of volcaniclastic & pelagic origin.

Initially, volcaniclastics interfinger with a backgroundof pelagic clays.

As subsidence continues & outstrips sedimentsupply, seafloor descends below CCD accumulatessiliceous rather than calcareous clays.

Clastic wedges into landward edge of basin fromcontinent.


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Back-arc Basin


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Foreland BasinsBack-arc region floored by continental lithosphere flexural

subsidence coupled with major fold & thrust tectonics.

Contains 4 depositional zones Wedge top/ Piggy Back BasinsForedeepForebulgeBackbulge

Foredeep & Piggy-back Basins most common.

F l d B i S di Fill


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Early Stage deposits Limestones, deep-water muds &interbedded turbidite sandstones Flysch"

Later Stage Transition to coarse-grained (upwardcoarsening) fluvial/alluvial clastic rocks Molasse".

Foreland Basins Sediment Fill


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Retro-arc foreland basins

Peripheral foreland Basin


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Basins in Intraplate SettingsRift BasinsWithin continental; Opening stage of Wilson

Cycle/continental break-up .

Long, narrow, linear; No or poor connection with sea.

MechanismsActive Rifting East African Rift

Passive Rifting

Sediment FillCoarse, non-marine, alluvial, fluvial & lacustrinesiliciclastics & volcaniclastics texturally &

mineralogically immature.

Where periodic connection with sea(esp. in rift climaxphase) Evaporites (Jurassic of Gulf of Mexico & Texas).


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East African Rift Basin


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Proto Oceanic Rift Basins

Post-rift phase Basin floored with Oceanic crust.

Ex Red Sea, b/w Africa & Arabia;

Southern Red Sea young (5Ma) oceanic crust alongits axial zone, with flanking shelves underlain by

stretched continental lithosphere.

To South, transition to continental Afar Rift; To North,Gulf of Suez Rift.

Sediment FillSubsidence outpaces sediment supply.Number of distinctive facies associations indicative of

sediment starvation

Evaporites,Black organic-rich shale


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Red Sea Proto Oceanic Rift Basins


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Cross Section of Red Sea Rift


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Passive Margin BasinsAreas of high sedimentation rates large-listricgravity-driven faults common. In areas of low clasticsediment input Carbonate factories.

Eustasy, Tectonics & other factors(Climate, etc) control accomodation space & sediment availability, &hence sediment diistribution pattern


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References

OCW MITBasin Analysis: Principles & Applications Allen & Allen (2005)

Plate Tectonics: Continental Drift & Mountain Building Frisch, Meschede & Blakey(2011)

Principles of Sedimentary Basin Analysis A.D.Miall (2000)Sedimentary Basins: Evolution, Facies & Sediemntary Budget Gerhard Einsele

(2000)Global tectonics Kearney, Klepeis & Vine (2009)

Physical Principles of Sedimentary Basins Magnus Wangen (2010)Petroleum Geoscience J.Gluyas & R.Swarbrick (2006)Petroleum Geoscience: From Sedimentary Environments to Rock Physics

K.Bjorlykke (2010)Petrology of Sedimentary Rocks Sam Boggs Jr. (2009)Principles of Sedimentology & Stratigraphy Sam Boggs Jr. (2005)

Sedimentology & Stratigraphy Gary Nichols (2009)Applied Sedimentology Richard C. Selley (2000)Earths Dynamic Systems W.K.Hamblin & E.H.ChristiansenEarth Structure: An Intro to Structural geology & Tectonics Pluijm & Marshak

(2004)


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Thank You

sedimentary basins & their sedimentation pattern

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