basics of sequence strat

“Sequence Stratigraphy – Basics”C. G. St. C. Kendall

Sequence Stratigraphy - Sequence Stratigraphy - IntroductionIntroduction

Fall 2007Fall 2007

Professor Christopher G. St. C. KendallProfessor Christopher G. St. C. Kendall

[email protected] [email protected] 803 – 777 2410803 – 777 2410

Sequence Stratigraphy Sequence Stratigraphy

A framework of genetically A framework of genetically related stratigraphic facies related stratigraphic facies geometries and their geometries and their bounding surfaces used to bounding surfaces used to determine depositional determine depositional settingsetting

“Sequence Stratigraphy – Basics”C. G. St. C. KendallPhoto by Torbjörn TörnqvisPhoto by Torbjörn Törnqvis

Use a framework of genetically Use a framework of genetically related stratigraphic facies related stratigraphic facies geometries and their bounding geometries and their bounding surfaces to determine their surfaces to determine their depositional settingdepositional setting

Book Cliffs – Prograding Cretaceous ShorelineBook Cliffs – Prograding Cretaceous Shoreline


Use a framework of genetically Use a framework of genetically related stratigraphic facies related stratigraphic facies geometries and their bounding geometries and their bounding surfaces to determine their surfaces to determine their depositional settingdepositional setting



Establish a framework of geneticallyEstablish a framework of geneticallyrelated stratigraphic facies geometriesrelated stratigraphic facies geometries

and their bounding surfaces toand their bounding surfaces todetermine depositional settingdetermine depositional setting


Barrier IslandBarrier IslandBarrier IslandBarrier Island


CoastCoastTypesTypesCoastCoastTypesTypes


Interpretation involves: Interpretation involves: Identify subdividing "Identify subdividing "surfacessurfaces" enveloping " enveloping

““discrete sediment body geometriesdiscrete sediment body geometries” of ” of sedimentary section. sedimentary section.

BackstripBackstrip geometries from oldest to youngest geometries from oldest to youngest ReassembleReassemble these in order of formation, these in order of formation,

using subdividing surfaces, geometry, using subdividing surfaces, geometry, lithofacies & fauna to interpret the evolving lithofacies & fauna to interpret the evolving character of depositional settingcharacter of depositional setting

Remember:-Remember:-‘‘‘‘Each stratal unit is defined and identified Each stratal unit is defined and identified only by physical relationships of the strata, only by physical relationships of the strata, including lateral continuity and geometry of including lateral continuity and geometry of the surfaces bounding the units, vertical the surfaces bounding the units, vertical stacking patterns, and lateral geometry of stacking patterns, and lateral geometry of the strata within the units." (Van Wagoner the strata within the units." (Van Wagoner et al., 1990).et al., 1990).


The surfaces subdividing sedimentary section The surfaces subdividing sedimentary section are fundamental to sequence stratigraphic are fundamental to sequence stratigraphic interpretationinterpretation

As understanding of sedimentary systems & As understanding of sedimentary systems & interpretation improves nomenclature of each interpretation improves nomenclature of each surface can change surface can change

Changes in nomenclature often confuse a Changes in nomenclature often confuse a scientific methodology over laden with complex scientific methodology over laden with complex multi-syllable termsmulti-syllable terms

Surface can be given names used before for Surface can be given names used before for different surfacedifferent surface

Innocent geologists, not knowing terminology Innocent geologists, not knowing terminology has been changed & lacking understanding of has been changed & lacking understanding of reason for change, may feel they are going reason for change, may feel they are going stark staring madstark staring mad


Sequence StratigraphySequence StratigraphySequence StratigraphySequence Stratigraphy

Surfaces of erosion & non-deposition (Surfaces of erosion & non-deposition (Sequence Sequence Boundaries, Forced Regression Erosion Surface, Boundaries, Forced Regression Erosion Surface, Regressive Surface of Marine ErosionRegressive Surface of Marine Erosion))

Flooding (Flooding (Trangressive SurfacesTrangressive Surfaces [TS or [TS or Max Max Regressive SurfaceRegressive Surface] &/or ] &/or maximum flooding maximum flooding surfacessurfaces [mfs] [mfs] Ravinement SurfacesRavinement Surfaces [RS- [RS- transgressive )transgressive )

Subdivision & interpretation of Subdivision & interpretation of sedimentary record using a sedimentary record using a framework framework surfacessurfaces seen in outcrops, well logs, & 2- seen in outcrops, well logs, & 2-D and 3-D seismic. D and 3-D seismic. Include:Include:

This framework used to predict the This framework used to predict the extent of sedimentary facies geometry, extent of sedimentary facies geometry, lithologic character, grain size, sorting & lithologic character, grain size, sorting & reservoir qualityreservoir quality



Surfaces of erosion & non-deposition Surfaces of erosion & non-deposition ((sequence boundariessequence boundaries))

Flooding (Flooding (trangressive surfaces [TS] &/or trangressive surfaces [TS] &/or maximum flooding surfaces [mfs]maximum flooding surfaces [mfs]))

Subdivision & interpretation of sedimentary record using a framework surfaces seen in outcrops, well logs, & 2-D and 3-D seismic. Include:

This framework used to predict the extent of sedimentary facies geometry, lithologic character, grain size, sorting & reservoir quality


Lecture Series OverviewLecture Series OverviewLecture Series OverviewLecture Series Overview Sequence stratigraphy & stratigraphic Sequence stratigraphy & stratigraphic

surfacessurfaces Basics: Ideal ‘sequence’ of Vail et al 1977 & Basics: Ideal ‘sequence’ of Vail et al 1977 &

associated terminologyassociated terminology Clastic system response to changing sea Clastic system response to changing sea

level and rates of sedimentation - with movie level and rates of sedimentation - with movie Carbonate systems response to changing Carbonate systems response to changing

sea level and rates of sedimentation - with sea level and rates of sedimentation - with movie movie

Exercises – Sequence stratigraphy of Exercises – Sequence stratigraphy of carbonates and clastics from carbonates and clastics from chronostratigraphy, seismic, outcrop and chronostratigraphy, seismic, outcrop and well log characterwell log character



Surfaces of erosion & non-deposition Surfaces of erosion & non-deposition ((sequence boundariessequence boundaries))

Flooding (Flooding (trangressive surfaces [TS] &/or trangressive surfaces [TS] &/or maximum flooding surfaces [mfs]maximum flooding surfaces [mfs]))

Subdivision & interpretation of sedimentary record using a framework surfaces seen in outcrops, well logs, & 2-D and 3-D seismic. Include:

This framework used to predict the extent of sedimentary facies geometry, lithologic character, grain size, sorting & reservoir quality


Lecture – Points to NoteLecture – Points to NoteLecture – Points to NoteLecture – Points to Note Sequence are subdivided bySequence are subdivided by

Maximum Flooding Surfaces (mfs) Maximum Flooding Surfaces (mfs) Transgressive Surfaces (TS) Transgressive Surfaces (TS) Sequence Boundaries (SB)Sequence Boundaries (SB)

Arrangement of vertical succession or Arrangement of vertical succession or stacking patterns of unconfined sheetsstacking patterns of unconfined sheets

Prograde (step seaward) Prograde (step seaward) Retrograde (step landward) Retrograde (step landward) Aggrade (build vertically)Aggrade (build vertically)

Sheets and unconfined lobes containingSheets and unconfined lobes containingNon-amalgamated bodiesNon-amalgamated bodies

Incised topographic fillIncised topographic fillAmalgamated, multi-storied bodies (e.g. incised Amalgamated, multi-storied bodies (e.g. incised valleys)valleys)Within unconfined lobes Within unconfined lobes


Lecture OutlineLecture OutlineLecture OutlineLecture Outline Principles of StenoPrinciples of Steno Bedding Planes - How they form and Bedding Planes - How they form and

significance with respect to timesignificance with respect to time Branches of Stratigraphy - Lithostratigraphy, Branches of Stratigraphy - Lithostratigraphy,

Allostratigragraphy, and Sequence StratigraphyAllostratigragraphy, and Sequence Stratigraphy EventsEvents Sequence stratigraphic subdividing boundariesSequence stratigraphic subdividing boundaries Clastic Sequence Stratigraphic HierarchyClastic Sequence Stratigraphic Hierarchy Carbonate Sequence Stratigraphic HierarchyCarbonate Sequence Stratigraphic Hierarchy


Superposition: a succession of undeformed strata, Superposition: a succession of undeformed strata, oldest stratum its at base, with successive younger oldest stratum its at base, with successive younger ones above. Establishes relative ages of all strata & ones above. Establishes relative ages of all strata & their contained fossilstheir contained fossils

Original horizontality - stratification originally Original horizontality - stratification originally horizontal when sedimentary particles settled from horizontal when sedimentary particles settled from fluids under influence of gravity, so if steeply inclined fluids under influence of gravity, so if steeply inclined must have suffered subsequent disturbancemust have suffered subsequent disturbance

Original lateral continuity-strata originally extended in Original lateral continuity-strata originally extended in all directions until they thinned to zero or terminated all directions until they thinned to zero or terminated against edges of original basin of depositionagainst edges of original basin of deposition

Principles of StenoPrinciples of StenoPrinciples of StenoPrinciples of Steno


Steno’s PrinciplesSteno’s PrinciplesSteno’s PrinciplesSteno’s Principles


After Bruce Railsback, After Bruce Railsback, 20022002


Introduction to subdividing Introduction to subdividing surfacessurfaces

Introduction to subdividing Introduction to subdividing surfacessurfaces

High frequency surfaces define High frequency surfaces define bedsbeds

Lower frequency surfaces define Lower frequency surfaces define parasequencesparasequences (genetically related (genetically related cycles or packages of sediment) cycles or packages of sediment)

Lowest frequency major Lowest frequency major subdivisions in sedimentary subdivisions in sedimentary section - the section - the sequencesequence

Range fromRange from


Bounding surfaces & their Bounding surfaces & their definitiondefinitionBounding surfaces & their Bounding surfaces & their definitiondefinition

Internal and external surfaces of anyInternal and external surfaces of any

BedBed ParasequenceParasequence Stratigraphic Sequence Stratigraphic Sequence

Products of unique associations of Products of unique associations of processes.processes.


Bedding PlanesBedding PlanesBedding PlanesBedding Planes Beds are enclosed or bounded by sharply defined Beds are enclosed or bounded by sharply defined

upper & lower surfaces or bedding planes. upper & lower surfaces or bedding planes. These surfaces are easiest physical features of These surfaces are easiest physical features of

sedimentary rocks to identify in outcropsedimentary rocks to identify in outcrop Subdivide successions of sedimentary rock into Subdivide successions of sedimentary rock into

bedsbeds Used to determine relative order & timing of Used to determine relative order & timing of

accumulation of sediments forming bedsaccumulation of sediments forming beds Character of bedding planes, be they eroded, Character of bedding planes, be they eroded,

cemented, bored, bioturbated, or depositional cemented, bored, bioturbated, or depositional surfaces used to aid in interpretation of surfaces used to aid in interpretation of sedimentary rocks.sedimentary rocks.


Bedding PlanesBedding PlanesBedding PlanesBedding Planes Most probably formed by erosion of Most probably formed by erosion of

unconsolidated sediment collected at sediment unconsolidated sediment collected at sediment surface. Weight of sediment, just beneath surface. Weight of sediment, just beneath sediment surface, causes sediment to dewater, sediment surface, causes sediment to dewater, compact & become cohesivecompact & become cohesive

Less cohesive sediment of surface truncated & Less cohesive sediment of surface truncated & expose surface of firmer cohesive sediment expose surface of firmer cohesive sediment below at bedding plane surface in response to:below at bedding plane surface in response to:

Storm wavesStorm wavesFast flowing currents of water (say in tidal or fluvial Fast flowing currents of water (say in tidal or fluvial channels)channels)Turbid flow of a density currentTurbid flow of a density current


Bedding PlanesBedding PlanesBedding PlanesBedding Planes


Link between time, surfaces & Link between time, surfaces & layerslayersLink between time, surfaces & Link between time, surfaces & layerslayers

Sedimentary layering of a stratigraphic Sedimentary layering of a stratigraphic section has a vast array of dimensional section has a vast array of dimensional hierarchieshierarchies

Range from units millimeters thick that Range from units millimeters thick that might be formed over seconds to thousands might be formed over seconds to thousands of feet thick and formed of millions of yearsof feet thick and formed of millions of years

Each layer no matter its dimension and Each layer no matter its dimension and whatever the time involved in its whatever the time involved in its deposition, is bounded by surfaces that deposition, is bounded by surfaces that transgress timetransgress time


Beach Foreshore and Beach Foreshore and BackshoreBackshore

Beach Foreshore and Beach Foreshore and BackshoreBackshore



Foreshore swash units millimeters Foreshore swash units millimeters thick might have formed over seconds thick might have formed over seconds but preserve events the collectively but preserve events the collectively formed over weeks to monthsformed over weeks to months

Each layer no matter its dimension Each layer no matter its dimension and whatever the time involved in its and whatever the time involved in its deposition, is bounded by surfaces deposition, is bounded by surfaces that transgress timethat transgress time


Beach BackshoreBeach BackshoreLow Angle Swash EventsLow Angle Swash Events

Beach BackshoreBeach BackshoreLow Angle Swash EventsLow Angle Swash Events



Parasequence is a relatively Parasequence is a relatively conformable succession of genetically conformable succession of genetically related beds or bedsets (within a related beds or bedsets (within a parasequence set) bounded by parasequence set) bounded by marine flooding surfacesmarine flooding surfaces or their or their correlative surfaces (Van Wagoner, at correlative surfaces (Van Wagoner, at SEPM's 1985 Midyear Meeting). SEPM's 1985 Midyear Meeting).



Marine Flooding Surface




Walther’s LawWalther’s LawWalther’s LawWalther’s Law"Facies adjacent to one another in a continuous "Facies adjacent to one another in a continuous vertical sequence also accumulated adjacent to vertical sequence also accumulated adjacent to one another laterally".one another laterally".

Applies only to a section with no unconformities.Applies only to a section with no unconformities.

Applies to a section without subdividing diachronous Applies to a section without subdividing diachronous boundaries, including transgressive surfaces (TS) boundaries, including transgressive surfaces (TS) and the maximum flooding surfaces (mfs).and the maximum flooding surfaces (mfs).

The interpretation of depositional setting for a The interpretation of depositional setting for a section cut by diachronous surfaces must section cut by diachronous surfaces must contravene Walther’s Lawcontravene Walther’s Law


ShelfShelfCycleCycleJamesJames

--VerticalVertical

AssociatioAssociationn

AccumulatAccumulateded

LaterallyLaterally

ShelfShelfCycleCycleJamesJames

--VerticalVertical

AssociatioAssociationn

AccumulatAccumulateded

LaterallyLaterally

ShoalingShoalingUpUp

CycleCycle


26oN

24oN

52oE

50 km

U N I T E D A R A B E M I R A T E S

S A U D IA R A B I A

A R A B I A N

G U L F

Q A T A R

O M A N

54oE

Dubai

Ras AlKhaimah

RasGhanada

ABUDHABI

Khor Al Bazam

JabalOdaid

G R E A T

P E A R

L

B A N K

B A R R I E R

Wind direction of “Shamal”

20

10

MASANDAMPENINSULA

40

40

10

20

40

40

10

10

1010

10

10

10

40

20

10

Jabal Dhanna

I R A N56oE

Strait o

f Horm

uz

20

40

40

N

Al Ain

GULF OFOMAN

Fujairah

Nort

h E

aste

rn C

oast

Nor

thw

est Co

ast

Central Coast

Western Coast

Major coastal provinces of United Arab Emirates & bathymetry of Southern Arabian Gulf in fathoms (modified from Purser, 1973).


Western Coastal Margin of the United Arab Emirates

Western Coast of the United Arab EmiratesWestern Coast of the United Arab Emirates


Earlier High Earlier High Energy BeachesEnergy Beaches

Earlier High Earlier High Energy BeachesEnergy Beaches

Supratidal Supratidal SabkhaSabkha

EvaporitesEvaporites

Supratidal Supratidal SabkhaSabkha

EvaporitesEvaporites

High IntertidalHigh IntertidalCyanobacterialCyanobacterial

FlatsFlats

High IntertidalHigh IntertidalCyanobacterialCyanobacterial

FlatsFlatsIntertidalIntertidal

CarbonateCarbonateFlatsFlats

IntertidalIntertidalCarbonateCarbonate

FlatsFlats


Tidal ChannelsTidal Channels

Intertidal Sand & Mud Flats

Intertidal Sand & Mud Flats

Hardg

roun

ds

Hardg

roun

ds

CyanobacterialMats

CyanobacterialMats

SabkhaSabkha

Beach

Ridg

es

Beach

Ridg

es


Anhydrite

Anhydrite

Washover Sediments

Washover Sediments

Cyanobacterial Peat

Cyanobacterial Peat

ShoalingShoalingUpUp

CycleCycle

The Ancient Egyptians Knew This Before WaltherThe Ancient Egyptians Knew This Before WaltherOr may be not?Or may be not?


Link between time, surfaces & Link between time, surfaces & layerslayers

Link between time, surfaces & Link between time, surfaces & layerslayers

Each layer no matter its dimension and Each layer no matter its dimension and whatever the time involved in its deposition, whatever the time involved in its deposition, is bounded by surfaces that transgress timeis bounded by surfaces that transgress time

The interpretation of depositional setting for The interpretation of depositional setting for a section cut by diachronous surfaces must a section cut by diachronous surfaces must contravene Walther’s Lawcontravene Walther’s Law

However we simplify this by assuming theHowever we simplify this by assuming theBounding surfaces &Bounding surfaces &

Layers of sedimentLayers of sediment

have the same agehave the same age


Link between time, surfaces & Link between time, surfaces & layerslayersLink between time, surfaces & Link between time, surfaces & layerslayers Application of Steno's principles and Application of Steno's principles and

Walther’s Law provide powerful and Walther’s Law provide powerful and useful simplifications that assume the useful simplifications that assume the sediments packaged by surfaces sediments packaged by surfaces accumulated within discrete moments of accumulated within discrete moments of time. time.

If one thinks about this, these If one thinks about this, these simplifications don’t contravene logic simplifications don’t contravene logic (which is literally Fuzzy) and it aids in the (which is literally Fuzzy) and it aids in the interpretation of the sedimentary section.interpretation of the sedimentary section.



SequenceSequence A relatively conformable succession of A relatively conformable succession of

genetically related strata bounded at their genetically related strata bounded at their upper surface and base by unconformities and upper surface and base by unconformities and their correlative conformities (their correlative conformities (Vail, et al., 1977Vail, et al., 1977

Sequence is composed of a succession of Sequence is composed of a succession of genetically linked deposition systems genetically linked deposition systems (systems tracts) and is interpreted to be (systems tracts) and is interpreted to be deposited between eustatic-fall inflection deposited between eustatic-fall inflection points (points (Posamentier, et al., 1988Posamentier, et al., 1988).).

The sequences and the system tracts they The sequences and the system tracts they enclose are subdivided and/or bounded by a enclose are subdivided and/or bounded by a variety of "key" surfaces that bound or variety of "key" surfaces that bound or envelope these discrete geometric bodies of envelope these discrete geometric bodies of sediment. They mark changes in depositional sediment. They mark changes in depositional regime "thresholds" across that boundary.regime "thresholds" across that boundary.


Bounding surfaces & their Bounding surfaces & their definitiondefinition

Bounding surfaces & their Bounding surfaces & their definitiondefinition

Stratigraphic SequenceStratigraphic Sequence


Branches of stratigraphyBranches of stratigraphyBranches of stratigraphyBranches of stratigraphy LithostratigraphyLithostratigraphy: maps lithofacies : maps lithofacies

independent of subdividing external & independent of subdividing external & internal boundaries internal boundaries

AllostratigraphyAllostratigraphy: bounding discontinuities : bounding discontinuities including erosion surfaces, marine flooding including erosion surfaces, marine flooding surfaces, tuffs, tempestite, and/or turbidite surfaces, tuffs, tempestite, and/or turbidite boundaries etc. as time markersboundaries etc. as time markers

Sequence StratigraphySequence Stratigraphy: higher level : higher level allostratigraphic model which interprets allostratigraphic model which interprets depositional origin of sedimentary strata as depositional origin of sedimentary strata as products of "relative sea level change"products of "relative sea level change"

Lithostratigraphy & Lithostratigraphy & AllostratigraphyAllostratigraphyLithostratigraphy & Lithostratigraphy & AllostratigraphyAllostratigraphy

Lithostratigraphy

Based onGross

Lithology

Allostratigraphy

Based onLithology & Surfaces

AllostratigrapAllostratigraphichicEvents & Events & SurfacesSurfaces

AllostratigrapAllostratigraphichicEvents & Events & SurfacesSurfaces


Sequence Sequence StratigraphicStratigraphic

Higher level Higher level allostratigraphic allostratigraphic

model that enables model that enables interpretation of interpretation of

sedimentary strata sedimentary strata as products of as products of

"relative sea level "relative sea level change"change"


Sequence StratigraphySequence StratigraphyHigher level allostratigraphic model that Higher level allostratigraphic model that interprets sedimentary strata in terms of interprets sedimentary strata in terms of bounding surfaces that are the products bounding surfaces that are the products of "relative sea level change"of "relative sea level change"


Bounding SurfacesBounding SurfacesBounding SurfacesBounding Surfaces

Relative time framework to sedimentary Relative time framework to sedimentary successionsuccession

Better understanding inter-relationship Better understanding inter-relationship of depositional settings & their lateral of depositional settings & their lateral correlationcorrelation

Subdivide sedimentary rock. BSubdivide sedimentary rock. Best understood by iteratively applying conceptual models that link processes that formed them. Provide:-Provide:-


Sequence Stratigraphy Sequence Stratigraphy Sequence Stratigraphy Sequence Stratigraphy Study of rock relationships within a time-Study of rock relationships within a time-

stratigraphic framework of repetitive, stratigraphic framework of repetitive, genetically related strata bounded by genetically related strata bounded by surfaces of erosion or non-deposition, or surfaces of erosion or non-deposition, or their correlative conformities (Posamentier their correlative conformities (Posamentier et al., 1988; Van Wagoner et al., 1988). et al., 1988; Van Wagoner et al., 1988).

Implicit but sometimes unstated connection Implicit but sometimes unstated connection between the external and internal surfaces between the external and internal surfaces of a sequence and base level change.of a sequence and base level change.


Sequence Stratigraphic Sequence Stratigraphic SurfacesSurfacesSequence Stratigraphic Sequence Stratigraphic SurfacesSurfaces

Sequence stratigraphy is based on the Sequence stratigraphy is based on the application of the systematic application of the systematic subdivision of the section by well subdivision of the section by well defined surfacesdefined surfaces

These surfaces are used to provide a These surfaces are used to provide a frame work to the interpretation of the frame work to the interpretation of the depositional settings of the sedimentary depositional settings of the sedimentary sectionsection

This interpretation is then is used to This interpretation is then is used to predict the extent and character of the predict the extent and character of the component sedimentary faciescomponent sedimentary facies


Sequence Boundary (SB)Sequence Boundary (SB)Sequence Boundary (SB)Sequence Boundary (SB) Envelope SequenceEnvelope Sequence Significant erosional unconformity & correlative Significant erosional unconformity & correlative

disconformity formed bydisconformity formed by drop in base level (sea drop in base level (sea level?)level?)

Erodes subaerially exposed sediment surface of Erodes subaerially exposed sediment surface of earlier sequence or sequencesearlier sequence or sequences

DiachronousDiachronous boundary between underlying boundary between underlying Highstand System Tract (HST) & overlying Falling Highstand System Tract (HST) & overlying Falling Stage System Tract (FSST) or Early Lowstand Stage System Tract (FSST) or Early Lowstand System Tract (ELST)System Tract (ELST)

Erode surface of downstepping sediments Erode surface of downstepping sediments deposited during accompanying forced regression deposited during accompanying forced regression associated with sea level fall associated with sea level fall


Sequence Boundary (SB)Sequence Boundary (SB)Sequence Boundary (SB)Sequence Boundary (SB)


Characteristics of Characteristics of Sequence Boundary (SB) Sequence Boundary (SB) from seismicfrom seismic

Characteristics of Characteristics of Sequence Boundary (SB) Sequence Boundary (SB) from seismicfrom seismic Defined by erosion or truncation of underlying Defined by erosion or truncation of underlying

reflectors or the correlative conformityreflectors or the correlative conformity Can be inferred from onlapping reflectors Can be inferred from onlapping reflectors

overlying a surfaceoverlying a surface Should the upper surface of a falling stage Should the upper surface of a falling stage

system tract be eroded when a shoreline is system tract be eroded when a shoreline is forced seaward (a forced regression!) by a forced seaward (a forced regression!) by a drop in sea level (or base level) the drop in sea level (or base level) the interpretation of a sequence boundary is interpretation of a sequence boundary is ambiguousambiguous


Characteristics of Sequence Characteristics of Sequence Boundary (SB) from well logs, Boundary (SB) from well logs, core & outcropcore & outcrop

Characteristics of Sequence Characteristics of Sequence Boundary (SB) from well logs, Boundary (SB) from well logs, core & outcropcore & outcrop Defined by erosion or incision of underlying Defined by erosion or incision of underlying

flooding surfaces (mfs and TS)flooding surfaces (mfs and TS) Inferred from interruption in the lateral Inferred from interruption in the lateral

continuity of these surfaces continuity of these surfaces


Transgressive Surface (TS)Transgressive Surface (TS)Transgressive Surface (TS)Transgressive Surface (TS) Product of rise in base level (sea level?)Product of rise in base level (sea level?) Lies at boundary between underlying Late Lies at boundary between underlying Late

Lowstand System Tract (LLST) and the overlying Lowstand System Tract (LLST) and the overlying Transgressive system tract (TST) Transgressive system tract (TST)

Marine-flooding surface that forms first significant Marine-flooding surface that forms first significant flooding surface in a sequence - often marking flooding surface in a sequence - often marking base of most prominent onlap. base of most prominent onlap.

Formed when rate of creation of accommodation Formed when rate of creation of accommodation space is greater that the rate of sediment supply. space is greater that the rate of sediment supply.

In rimmed carbonate platforms, the rate of In rimmed carbonate platforms, the rate of sediment supply may keep pace with the rate of sediment supply may keep pace with the rate of relative sea-level rise and thus TS marks change relative sea-level rise and thus TS marks change from a progradational to an aggradational from a progradational to an aggradational parasequence stacking patternsparasequence stacking patterns. .


Transgressive Surface (TS)Transgressive Surface (TS)Transgressive Surface (TS)Transgressive Surface (TS)


Characteristics of Characteristics of Transgressive Surface [TS) Transgressive Surface [TS) from seismicfrom seismic

Characteristics of Characteristics of Transgressive Surface [TS) Transgressive Surface [TS) from seismicfrom seismic

Defined by onlapping reflectors over and onto a surface Defined by onlapping reflectors over and onto a surface (SB (SB


Characteristics of Characteristics of Transgressive Surface [TS) - Transgressive Surface [TS) - well logs, core & outcropwell logs, core & outcrop


Defined by erosion or incision of underlying Defined by erosion or incision of underlying onlapped sediment (Ravinement)onlapped sediment (Ravinement)

Inferred from presence of Glossifungites in Inferred from presence of Glossifungites in this surfacethis surface

Inferred from presence of nick or neck on Inferred from presence of nick or neck on resistivity logs caused by presence of resistivity logs caused by presence of carbonate cements probably derived from carbonate cements probably derived from the carbonate fauna eroded during the the carbonate fauna eroded during the Ravinement Ravinement




Defined by erosion or incision of Defined by erosion or incision of underlying onlapped sediment underlying onlapped sediment (Ravinement)(Ravinement)




Inferred from presence of Glossifungites Inferred from presence of Glossifungites in this surface)in this surface)




Inferred from presence of nick or neck on Inferred from presence of nick or neck on resistivity logs caused by presence of resistivity logs caused by presence of carbonate cements probably derived from carbonate cements probably derived from the carbonate fauna eroded during the the carbonate fauna eroded during the RavinementRavinement


Transgressive Surface [TS) Transgressive Surface [TS) - well logs, core & outcropwell logs, core & outcropTransgressive Surface [TS) Transgressive Surface [TS) - well logs, core & outcropwell logs, core & outcrop

Section


Transgressive Surface [TS) Transgressive Surface [TS) - well logs, core & outcropwell logs, core & outcropTransgressive Surface [TS) Transgressive Surface [TS) - well logs, core & outcropwell logs, core & outcrop

TS


Maximum Flooding Maximum Flooding Surface (mfs)Surface (mfs)Maximum Flooding Maximum Flooding Surface (mfs)Surface (mfs) Product of maximum flooding or Product of maximum flooding or

transgression of shelf or stillstand in base transgression of shelf or stillstand in base level (sea level?)level (sea level?)

Lies at the boundary between the underlying Lies at the boundary between the underlying Transgressive system tract (TST) and the Transgressive system tract (TST) and the overlying High stand system tract (HST) overlying High stand system tract (HST)

Often expressed as a downlap surface.Often expressed as a downlap surface. Marine shelf and basinal sediments Marine shelf and basinal sediments

associated with this surface product of slow associated with this surface product of slow rates of deposition of pelagic-hemipelagic rates of deposition of pelagic-hemipelagic sedimentssediments

Make up condensed section and are usually Make up condensed section and are usually thinthin


Maximum Flooding Maximum Flooding Surface (mfs)Surface (mfs)Maximum Flooding Maximum Flooding Surface (mfs)Surface (mfs)


Often expressed as a downlap surface.Often expressed as a downlap surface.

Characteristics of Maximum Characteristics of Maximum Flooding Surface [mfs) from Flooding Surface [mfs) from seismicseismic



Defined as lying immediately below the Defined as lying immediately below the downlapping reflectors prograding downlapping reflectors prograding reflectors of the HST reflectors of the HST




Defined by organic often radioactive (big Defined by organic often radioactive (big kicks on gamma ray logs) black shaleskicks on gamma ray logs) black shales

Not infrequently overlain by coarser Not infrequently overlain by coarser sediments (often sand sized)sediments (often sand sized)

Inferred from presence of condensed Inferred from presence of condensed faunal associationfaunal association

Inferred from presence of finest grain sizeInferred from presence of finest grain size

Characteristics of Maximum Characteristics of Maximum Flooding Surface [mfs) from well Flooding Surface [mfs) from well logs, cores, & outcroplogs, cores, & outcrop

Characteristics of Maximum Characteristics of Maximum Flooding Surface [mfs) from well Flooding Surface [mfs) from well logs, cores, & outcroplogs, cores, & outcrop


Maximum Maximum FloodingFloodingSurfaceSurface[mfs) [mfs)

well logs, well logs, core & core & outcropoutcrop

Maximum Maximum FloodingFloodingSurfaceSurface[mfs) [mfs)

well logs, well logs, core & core & outcropoutcrop

MFSMFS

After Hanford


Maximum FloodingMaximum FloodingSurface [mfs) Surface [mfs)

well logs, core & well logs, core & outcropoutcrop

Maximum FloodingMaximum FloodingSurface [mfs) Surface [mfs)

well logs, core & well logs, core & outcropoutcrop

MFSMFS

After Hanford


MaximuMaximum m

FloodingFloodingSurface Surface [mfs) [mfs) well well logs, logs,

core & core & outcropoutcrop

MaximuMaximum m

FloodingFloodingSurface Surface [mfs) [mfs) well well logs, logs,

core & core & outcropoutcrop

MFSMFS

After Hanford


Maximum Flooding Maximum Flooding Surface [mfs) - well logs, Surface [mfs) - well logs,

core & outcropcore & outcrop

Maximum Flooding Maximum Flooding Surface [mfs) - well logs, Surface [mfs) - well logs,

core & outcropcore & outcrop

mfs

After Coe et al


Maximum Flooding Maximum Flooding Surface (mfs)Surface (mfs)Maximum Flooding Maximum Flooding Surface (mfs)Surface (mfs) Product of maximum flooding or Product of maximum flooding or

transgression of shelf or stillstand in base transgression of shelf or stillstand in base level (sea level?)level (sea level?)

Lies at boundary between underlying Lies at boundary between underlying Transgressive system tract (TST) and Transgressive system tract (TST) and overlying High stand system tract (HST) overlying High stand system tract (HST)

Often expressed as a downlap surface.Often expressed as a downlap surface. Marine shelf and basinal sediments Marine shelf and basinal sediments

associated with this surface product of slow associated with this surface product of slow rates of deposition of pelagic-hemipelagic rates of deposition of pelagic-hemipelagic sedimentssediments

Often associated with condensed sections, Often associated with condensed sections, high gamma ray signals and are usually thinhigh gamma ray signals and are usually thin


DefinitionsDefinitionsDefinitionsDefinitionssedimentsediment:: unconsolidated* material that is unconsolidated* material that is

produced on Earth’s surface by the produced on Earth’s surface by the disaggregation of pre-existing rocks disaggregation of pre-existing rocks

sedimentary rocksedimentary rock:: a consolidated body a consolidated body formed from sediments or formed from sediments or solutessolutes that are that are transported and deposited by gravity, transported and deposited by gravity, biologic activity, or a biologic activity, or a fluidfluid and then and then lithifiedlithified by the combined effects of by the combined effects of compactioncompaction and and cementationcementation

sedimentologysedimentology:: the study of the the study of the productionproduction, , transporttransport,, and and depositiondeposition of sediment of sediment

** some exceptions applysome exceptions apply


stratastrata: : layers of (usually sedimentary) rocklayers of (usually sedimentary) rock

stratigraphystratigraphy:: 1.1. the description, study, and/or application the description, study, and/or application

of the composition of layered (usually of the composition of layered (usually sedimentary) rocks sedimentary) rocks

2.2. a a successionsuccession of layered rocks; of layered rocks; e.ge.g., the ., the stratigraphy of South Carolinastratigraphy of South Carolina

basinbasin: : 1.1. a region of potential sediment a region of potential sediment

accumulationaccumulation generally caused by generally caused by subsidencesubsidence

2.2. the largest possible body of related and the largest possible body of related and once-contiguous* strata; once-contiguous* strata; e.g.e.g., the , the Appalachian basinAppalachian basin

* some exceptions apply* some exceptions apply

DefinitionsDefinitionsDefinitionsDefinitions


facierefaciere: : to send, to put, to place, to send, to put, to place, to maketo make faciesfacies: : outward appearance, sight, form, shapeoutward appearance, sight, form, shape

faciesfacies: : the face; the general aspect of any the face; the general aspect of any group of organisms or of rocks group of organisms or of rocks ((Webster’s Webster’s 19451945))

faciesfacies: : a rock distinguished from others by a rock distinguished from others by its appearance or compositionits appearance or composition (www.dictionary.com)(www.dictionary.com)



stratastrata: : layers of (usually sedimentary) rocklayers of (usually sedimentary) rock

stratigraphystratigraphy:: 1.1. the description, study, and/or application the description, study, and/or application

of the composition of layered (usually of the composition of layered (usually sedimentary) rocks sedimentary) rocks

2.2. a a successionsuccession of layered rocks; of layered rocks; e.ge.g., the ., the stratigraphy of South Carolinastratigraphy of South Carolina

basinbasin: : 1.1. a region of potential sediment a region of potential sediment

accumulationaccumulation generally caused by generally caused by subsidencesubsidence

2.2. the largest possible body of related and the largest possible body of related and once-contiguous* strata; once-contiguous* strata; e.g.e.g., the , the Appalachian basinAppalachian basin

** some exceptions apply some exceptions apply



Sedimentary FaciesSedimentary FaciesSedimentary FaciesSedimentary Facies


Sedimentary FaciesSedimentary FaciesSedimentary FaciesSedimentary Facies faciesfacies: : the total textural, compositional and structural the total textural, compositional and structural

characteristics of a sedimentary deposit resulting from characteristics of a sedimentary deposit resulting from accumulation and modification in a particular accumulation and modification in a particular environment.environment.


• grain size, sorting, roundinggrain size, sorting, rounding

• lithologylithology

• sedimentary structuressedimentary structures

• bedding typebedding type




Sedimentary FaciesSedimentary FaciesSedimentary FaciesSedimentary Facies faciesfacies: : the total textural, compositional and the total textural, compositional and

structural characteristics of a sedimentary deposit structural characteristics of a sedimentary deposit resulting from accumulation and modification in a resulting from accumulation and modification in a particular environment.particular environment.

EX: EX: well-sorted, moderately rounded, trough cross-stratified, well-sorted, moderately rounded, trough cross-stratified, horizontally burrowed & normally graded arkosic coarse horizontally burrowed & normally graded arkosic coarse sandstonesandstone


Lithofacies & Lithofacies Lithofacies & Lithofacies CodesCodesLithofacies & Lithofacies Lithofacies & Lithofacies CodesCodes

Sedimentary facies often get reduced to Sedimentary facies often get reduced to lithofacieslithofacies which detail grain-size, composition, which detail grain-size, composition, and dominant sedimentary structures onlyand dominant sedimentary structures only

EX: planar cross-stratified gravel, inversely graded EX: planar cross-stratified gravel, inversely graded massive sandstonemassive sandstone

This has led to lithofacies codes (after Miall, 1978).This has led to lithofacies codes (after Miall, 1978).

EX: Gmm, St, FslEX: Gmm, St, Fsl




facies assemblagefacies assemblage:: collection of multiple facies collection of multiple facies resulting from genetically related accumulation and resulting from genetically related accumulation and modification.modification.

EX: lenticularly bedded stratified pebble conglomerate EX: lenticularly bedded stratified pebble conglomerate with subordinate planar cross-stratified sandstone with subordinate planar cross-stratified sandstone

OR: fluvial channel lithofacies assemblageOR: fluvial channel lithofacies assemblage


Facies AssemblageFacies AssemblageFacies AssemblageFacies Assemblage


Depositional SystemsDepositional SystemsDepositional SystemsDepositional Systems depositional systemdepositional system:: assemblage of multiple assemblage of multiple

process-related sedimentary facies assemblages, process-related sedimentary facies assemblages, commonly identified by the geography in which commonly identified by the geography in which deposition occurs.deposition occurs.

EX: nearshore depositional system, deep marine EX: nearshore depositional system, deep marine depositional system, glacial depositional system, fluvial depositional system, glacial depositional system, fluvial depositional systemdepositional system

NBNB depositional systems are: depositional systems are:modern featuresmodern features

used to interpret ancient sedimentary successionsused to interpret ancient sedimentary successions


Sequence stratigraphic Sequence stratigraphic analysisanalysisSequence stratigraphic Sequence stratigraphic analysisanalysis

Subdivision of section into sequences, Subdivision of section into sequences, parasequences and beds.parasequences and beds.

Link conceptual models with mix of Link conceptual models with mix of components of the individual sequence, components of the individual sequence, parasequence or beds parasequence or beds

Use these to explain the depositional Use these to explain the depositional setting in terms of their lithology, grain setting in terms of their lithology, grain size, sedimentary structures, contacts size, sedimentary structures, contacts character (gradational, abrupt) etccharacter (gradational, abrupt) etc

This analysis involvesThis analysis involves


SequenceSequenceStratigraphiStratigraphi

ccAnalysisAnalysis

SequenceSequenceStratigraphiStratigraphi

ccAnalysisAnalysis


Clastic Sequence Stratigraphic Clastic Sequence Stratigraphic HierarchiesHierarchies



Clastic Sequence Clastic Sequence Stratigraphic HierarchiesStratigraphic Hierarchies

Clastic Sequence Clastic Sequence Stratigraphic HierarchiesStratigraphic Hierarchies


CLASTIC SEQUENCE CLASTIC SEQUENCE HIERARCHYHIERARCHYCLASTIC SEQUENCE CLASTIC SEQUENCE HIERARCHYHIERARCHY

SHELF & MARGIN COMPLEX – Mix of shelf, SHELF & MARGIN COMPLEX – Mix of shelf, coastal (barrier & deltaic) & adjacent basin & coastal (barrier & deltaic) & adjacent basin & fan facies evolving in response to complete & fan facies evolving in response to complete & complex cycles of changing base level & complex cycles of changing base level & paleogeographypaleogeography

STACKED CYCLES OF BEDS – Vertical character STACKED CYCLES OF BEDS – Vertical character of beds from varying depositional settingsof beds from varying depositional settings

BEDDING – Internal character including BEDDING – Internal character including lithology, geometry, sedimentary structures, & lithology, geometry, sedimentary structures, & faunafauna

ALLOCHEMS – Lthological components, their ALLOCHEMS – Lthological components, their cementation & diagenesiscementation & diagenesis


ClasticClasticSequenceSequenceStratigrapStratigrap

hichicHierarchieHierarchie

ss

ClasticClasticSequenceSequenceStratigrapStratigrap

hichicHierarchieHierarchie

ss


Establish a framework of geneticallyEstablish a framework of geneticallyrelated stratigraphic facies geometriesrelated stratigraphic facies geometries

and their bounding surfaces toand their bounding surfaces todetermine depositional settingdetermine depositional setting


CoastCoastTypesTypesCoastCoastTypesTypes


Lst Sequence Stratigraphic Lst Sequence Stratigraphic HierarchiesHierarchies

Lst Sequence Stratigraphic Lst Sequence Stratigraphic HierarchiesHierarchies


CARBONATE SEQUENCE CARBONATE SEQUENCE HIERARCHYHIERARCHYCARBONATE SEQUENCE CARBONATE SEQUENCE HIERARCHYHIERARCHY SHELF COMPLEX – Mix of shelf, shelf margin & SHELF COMPLEX – Mix of shelf, shelf margin &

adjacent basin facies evolving in response to adjacent basin facies evolving in response to complete & complex cycles of changing base level complete & complex cycles of changing base level & paleogeography& paleogeography

MARGIN COMPLEX – Shelf, shelf margin & adjacent MARGIN COMPLEX – Shelf, shelf margin & adjacent basin facies evolving in response to a cycle in basin facies evolving in response to a cycle in changing base levelchanging base level

STACKED CYCLES OF BEDS – Vertical character of STACKED CYCLES OF BEDS – Vertical character of beds from varying depositional settingsbeds from varying depositional settings

BEDDING – Internal character including lithology, BEDDING – Internal character including lithology, geometry, sedimentary structures, & faunageometry, sedimentary structures, & fauna

ALLOCHEMS – Lthological components, their ALLOCHEMS – Lthological components, their cementation & diagenesiscementation & diagenesis


Hierarchy of Carbonate Hierarchy of Carbonate Shelf Architectural Shelf Architectural

ElementsElements

Hierarchy of Carbonate Hierarchy of Carbonate Shelf Architectural Shelf Architectural

ElementsElements

Shelfmargincomplex

HST margincomplex

MARGINCOMPLEX

Stacked Cycles ofBeds Component

Grains

PROGRADING MARGINPROGRADING MARGIN

Beds

SHELFCOMPLEX

PROGRADING MARGINPROGRADING MARGIN

ONLAPPING MARGINONLAPPING MARGINPROGRADING MARGINPROGRADING MARGIN

STACKESTACKEDD

BEDBEDCYCLESCYCLES

BED,BED,LITHOLOGY,LITHOLOGY,

SEDIMENTARYSEDIMENTARYSTRUCTURESSTRUCTURES

FAUNAFAUNA

ALLOCHEMSALLOCHEMSCEMENTATIONCEMENTATION& DIAGENESIS& DIAGENESIS


Lecture Ends!!Lecture Ends!!Lecture Ends!!Lecture Ends!!

And so to lunchAnd so to lunch

basics of sequence strat

Documents

framework surfaces

bounding surfaces

subdividing surfaces

ideal sequence of vail

stratigraphic interpretation

kendall lecture points

d seismic

regression erosion surface