GE0-3112GE0-3112 Sedimentary processes and products Sedimentary processes and products

Lecture 1. Depositional controlsLecture 1. Depositional controls

Geoff CornerGeoff CornerDepartment of GeologyDepartment of GeologyUniversity of TromsøUniversity of Tromsø20062006

Literature:Literature:- Reading, 1996, Ch.2. Controls on the - Reading, 1996, Ch.2. Controls on the

sedimentary rock record.sedimentary rock record.- Leeder, 1999, ch. 1, 2, 13, 14, 15, 27, 28- Leeder, 1999, ch. 1, 2, 13, 14, 15, 27, 28

Depositional controlsDepositional controls►Sediment supplySediment supply►Accomodation spaceAccomodation space

Corner, in press

Sediment supplySediment supply

A) Terrigenous systemsA) Terrigenous systems

(allogenic, extrabasinal sediment (allogenic, extrabasinal sediment source) –clastic sediments transported source) –clastic sediments transported into the basin.into the basin.

B) Biochemical/chemical systemsB) Biochemical/chemical systems

(autogenic, intrabasinal sediment (autogenic, intrabasinal sediment source) – carbonate and other source) – carbonate and other sediments produced in the basin.sediments produced in the basin.

Sediment supplySediment supply► Variations in:Variations in:

Volume and rate of deliveryVolume and rate of delivery Grain size (calibre), etc.Grain size (calibre), etc. Petrographic composition (siliciclastic, carbonate)Petrographic composition (siliciclastic, carbonate) Mechanism of delivery (process)Mechanism of delivery (process)

► Determined by:Determined by: Bedrock geologyBedrock geology Tectonics/reliefTectonics/relief ClimateClimate Basinal water chemistry (for carbinates, etc.)Basinal water chemistry (for carbinates, etc.)

► (Denudation processes (weathering and erosion) and their (Denudation processes (weathering and erosion) and their intensity– dependent upon:intensity– dependent upon: reliefrelief Climate)Climate)

Sediment source (clastics)Sediment source (clastics)

►WeatheringWeathering

Sediment source (clastics)Sediment source (clastics)

►WeatheringWeathering►Mass-wastingMass-wasting

Sediment source (clastics)Sediment source (clastics)

►WeatheringWeathering►Mass-wastingMass-wasting►ErosionErosion

Sediment source (clastics)Sediment source (clastics)

►WeatheringWeathering►Mass-wastingMass-wasting►ErosionErosion►AttritionAttrition

Source areaSource area

►ReliefRelief High reliefHigh relief Low reliefLow relief

Source areaSource area

►ReliefRelief►BedrockBedrock

Hard crystallineHard crystalline Soft sedimentarySoft sedimentary

Sediment delivery systemSediment delivery system

►GlaciersGlaciers►Mass-movementMass-movement►RiversRivers►WindWind►WavesWaves►Tidal and ocean currentsTidal and ocean currents

Accomodation spaceAccomodation space

►Basin morphologyBasin morphology►Base-levelBase-level

Corner, in press

Basin morphologyBasin morphology

► Fjord exampleFjord example

Corner, in press

Basin morphologyBasin morphology

► Tectonic basin Tectonic basin exampleexample

Basin morphologyBasin morphology

► Shelf exampleShelf example

Base levelBase level

►ConceptConcept►Sea-levelSea-level

Sea levelSea level

► Eustatic (global) sea Eustatic (global) sea level (eustasy)level (eustasy)

► Uplift/subsidence Uplift/subsidence (isostasy)(isostasy)

► Relative sea-levelRelative sea-level► Water depth Water depth

Coe & Church, in Coe (ed.) 2003

Transgression and regressionTransgression and regression

Galloway & Hobday 1996

Controls on deposition IIControls on deposition II

► Independent variablesIndependent variables►Extrinsic and intrinsic factorsExtrinsic and intrinsic factors

Controls on deposition IIControls on deposition II

► Independent Independent variables:variables: ClimateClimate TectonicsTectonics

Church & Coe, in Coe (ed.) 2003

ClimateClimate

MilankovitchMilankovitch

Controls on deposition IIControls on deposition II

► Independent variablesIndependent variables►Extrinsic and intrinsic factorsExtrinsic and intrinsic factors

Depositional geometryDepositional geometry

► ProgradationProgradation

► RetrogradationRetrogradation

► AggradationAggradation

Prothero & Schwab 1996

Facies models and depositonal Facies models and depositonal systemssystems

► FaciesFacies► Facies succession (vertical Facies succession (vertical

succession; fining-upward, succession; fining-upward, thickening-upward trends, thickening-upward trends, etc.)etc.)

► Architectural element - Architectural element - medium-scale three-medium-scale three-dimensional depositional dimensional depositional body characterised by a body characterised by a distinctive assemblage of distinctive assemblage of facies and geometry. facies and geometry.

► Depositional system - three-Depositional system - three-dimensional assemblage of dimensional assemblage of lithofacies genetically linked lithofacies genetically linked by active or inferred by active or inferred processes and environments.processes and environments.

Hierarchy of depositional Hierarchy of depositional elementselements

StrataStrata Depositional unitDepositional unit Example ExampleAssemblagesAssemblages

LaminaLamina BedformBedform Ripple Ripple Facies Facies

BedBed Bed/arch. elementBed/arch. element Bar Bar Facies ass./ Facies ass./

MemberMember Architectural elementArchitectural element Channel Channel arch.elementarch.element

FormationFormation Depositional basinDepositional basin Valley-fill Valley-fill Facies Facies assoc.assoc.

GroupGroup Basin/settingBasin/setting Foreland Foreland

Miall, in Walker & James (eds.) 1992

Hierarchy of depositional Hierarchy of depositional elementselements

Miall, in Walker & James (eds.) 1992

Facies analysisFacies analysis

► Key to Key to analysinganalysing deposits: meaningful deposits: meaningful identification of bounding surfaces, facies identification of bounding surfaces, facies associations and/or architectural elements.associations and/or architectural elements.

► Key to Key to understandingunderstanding deposits: deposits: interpretation of depositional elements with interpretation of depositional elements with reference to depositional modelsreference to depositional models

Depositional model =Depositional model =

process + bedforms/geometry + preserved process + bedforms/geometry + preserved depositsdeposits

FaciesFacies

Einsele 1992

Facies and facies codesFacies and facies codes

► FaciesFacies

Miall, in Walker & James (eds.) 1992

Facies successionsFacies successions

Miall, in Walker & James (eds.) 1992

Architectural elementsArchitectural elements

Miall, in Walker & James (eds.) 1992

Sequence stratigraphySequence stratigraphy

Reading 1996

Practical tips on Practical tips on sedimentological analysissedimentological analysis

►1. Think process1. Think process►2. Think three-dimensional2. Think three-dimensional►3. Think ’big picture’3. Think ’big picture’

Tip 1. Think ’process’Tip 1. Think ’process’

►Example 1 –climbing-ripple beddingExample 1 –climbing-ripple bedding

Tip 1. Think ’process’Tip 1. Think ’process’

►Example 2 Example 2

– – Fjord-valley fill Fjord-valley fill stratigraphystratigraphy

Glaciomarine deposition

A

Outlet glacier

Fjord glacier

Meltwater

B

Valley glacier

Meltwater

Glaciofluvialdelta

Valley glacier

CMeltwater

Marine deposition

Fluvialdelta

RiverD

Fluvial terracing

ERiver

Post

gla

cial

Degla

cial

Corner, in press

Deglacial-postglacial surface

I

IIIc

IVd

IIa

Df

Dv

PMaximum flooding surface

Regressive accretionary surface

Marine limit

I

I

IIIb

IIb

IIdIIc

IVc

Glacial trough

Cross section X - X’

X’X

A

BMarine limit

IVb

1

3 2

IIb

IIc

IIa

I

IVd

IId

Df

Dv

PIIIc

IVc

II

IIIIV

I

DTST (Df)

PRST (P)

DHST (Dv)

Time

Sea

leve

l

Regressive accretionary surface

PDvDf

Postglacial forced regressive (PRST)

Depositional episodes/sequence tracts

Deglacial (fjord glacier) transgressive (DTST)

Deglacial (valley glacier) highstand (DHST)

Bounding surfaces

Fluvial erosion surface

Deltaic erosion surface

Fluvial accretion surface

IV

III

Depositional elements

II

I

Fjord floor

Delta foreset

- Fluvial (P)IVd

Ice-contact (Df)

Glaciofluvial delta foreset (Df/Dv)

- Marine (P)IIc - Prodelta (P)IId

- Glaciomarine (Df/Dv)IIa/IIb

- Delta topset (P)IVc

IIIc - Delta foreset (P)

Terrace top

- Glaciofluvial delta topset (Df/Dv)IVa/IVb

IIIa/IIIb-

Transgressive systems tractTransgressive systems tract

Highstand systems tractHighstand systems tract

Forced-regressive systems tractForced-regressive systems tract

Corner, in press

Tip 2. Think ’3D’Tip 2. Think ’3D’

►Example 1 – Trace fossils in sectionExample 1 – Trace fossils in section

Tip 2. Think 3DTip 2. Think 3D

►Example 2 – primary sedimentary Example 2 – primary sedimentary structuresstructures

Tip 2. Think 3DTip 2. Think 3D

► Example 3 – Vertical Example 3 – Vertical (2D) sections(2D) sections

Vorren & Mangerud, in press

Tip 3. Think ’big picture’Tip 3. Think ’big picture’

►Spatial aspects of the systemSpatial aspects of the system►Time aspects and system controlsTime aspects and system controls

Glaciomarine deposition

A

Outlet glacier

Fjord glacier

Meltwater

B

Valley glacier

Meltwater

Glaciofluvialdelta

Valley glacier

CMeltwater

Marine deposition

Fluvialdelta

RiverD

Fluvial terracing

ERiver

Post

gla

cial

Degla

cial