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Sequence Stratigraphy Defined

Sequence StratigraphySequence Stratigraphy

Template Template for “for “Conceptual ModelsConceptual Models” ” Used to Interpret Used to Interpret

Depositional SystemsDepositional Systems- - beauty butbeauty but not truthnot truth? ? --

Christopher G. St. C. KendallChristopher G. St. C. KendallUniversity of South CarolinaUniversity of South Carolina

[email protected] [email protected] 803 978 7523803 978 7523


Why codify ‘rules’ for sequence Why codify ‘rules’ for sequence stratigraphic nomenclature?stratigraphic nomenclature?

We use We use common termscommon terms and know their and know their meaningmeaning

Have a Have a standard hierarchystandard hierarchy of subdivisions of subdivisions Have a Have a uniformuniform methodology methodology GuidanceGuidance for revision for revision Teaching resourceTeaching resource: each new generation of : each new generation of

students & practitioners have a common students & practitioners have a common understandingunderstanding


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 – Sequence Stratigraphy – TerminologyTerminologySequence Stratigraphy – Sequence Stratigraphy – TerminologyTerminologyStratigraphers have a Stratigraphers have a

position on position on terminology similar to terminology similar to the of Humpty the of Humpty Dumpty's from Lewis Dumpty's from Lewis Carroll’s Through the Carroll’s Through the Looking Glass Looking Glass

"When I use a word, it "When I use a word, it means just what I means just what I choose it to mean - choose it to mean - nothing more nor less".nothing more nor less".


Talk OrganizationTalk OrganizationTalk OrganizationTalk Organization Sedimentary Analysis & Sequence Sedimentary Analysis & Sequence

StratigraphyStratigraphy History of Sequence StratigraphyHistory of Sequence Stratigraphy Sequence Stratigraphy Analysis Sequence Stratigraphy Analysis

DefinedDefined Geometries & Stacking PatternsGeometries & Stacking Patterns System Tracts & Relative Sea LevelSystem Tracts & Relative Sea Level Bounding SurfacesBounding Surfaces Conceptual Models Conceptual Models Terminology That Should be DefinedTerminology That Should be Defined ConclusionsConclusions


Sequence Stratigraphy – The process Sequence Stratigraphy – The process Interpretation of the Sedimentary section Interpretation of the Sedimentary section involves: involves: From oldest to youngest, identify the From oldest to youngest, identify the subdividing subdividing surfacessurfaces that envelope & enclose the that envelope & enclose the discrete geometric bodies of sediment of the discrete geometric bodies of sediment of the sedimentary section & build a sedimentary section & build a templatetemplateBackstrip these geometries & then use the Backstrip these geometries & then use the templatetemplate of surfaces to of surfaces to reassemblereassemble them in them in order of their accumulationorder of their accumulationThe subdividing surfaces, geometry, lithofacies The subdividing surfaces, geometry, lithofacies & fauna are input to a & fauna are input to a conceptual modelconceptual model to to determine the evolving character of the determine the evolving character of the depositional settingdepositional setting

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


'Depositional' sequence Vail et 'Depositional' sequence Vail et al 1971al 1971

'Depositional' sequence Vail et 'Depositional' sequence Vail et al 1971al 1971


SBSBSBSB

mfsmfsmfsmfs

TSTSTSTS

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


Sedimentary AnalysisSedimentary AnalysisSedimentary AnalysisSedimentary AnalysisPotential flow of Potential flow of interpretationinterpretation

Scheme usedScheme usedto characterize to characterize depositional depositional systems so they systems so they can be comparedcan be compared

datadata

datadata

interpretationinterpretation




Power of Sequence Power of Sequence StratigraphyStratigraphyPower of Sequence Power of Sequence StratigraphyStratigraphy

Determines depositional setting by: Determines depositional setting by: Establishing the Establishing the orderorder in which strata were laid in which strata were laid

down indown in Explains the Explains the geometric hierarchygeometric hierarchy of sedimentary of sedimentary

strata & the elements they form strata & the elements they form Uses the major surfaces marking breaks in the Uses the major surfaces marking breaks in the

character of sedimentary section as a template character of sedimentary section as a template for for conceptual depositional modelsconceptual depositional models, independent , independent of time (relative ages)of time (relative ages)

Geologic time derived from: Geologic time derived from: Radiometric markersRadiometric markers Biostratigraphic markersBiostratigraphic markers


Building Block Sedimentary Fill Building Block Sedimentary Fill Hierarchy Hierarchy Building Block Sedimentary Fill Building Block Sedimentary Fill Hierarchy Hierarchy

Sediment body characterization in order Sediment body characterization in order of decreasing complexityof decreasing complexity

Complex SetComplex Set ComplexComplex StoryStory ElementElement BedBedThese are the fundamental components of These are the fundamental components of

Sequences and System tractsSequences and System tracts


Fluvial - Architectural Fluvial - Architectural ElementsElements

Fluvial - Architectural Fluvial - Architectural ElementsElements


Deepwater - Architectural Deepwater - Architectural ElementsElements









Hierarchy of Carbonate Hierarchy of Carbonate Shelf Architectural Shelf Architectural

ElementsElements

Hierarchy of Carbonate Hierarchy of Carbonate Shelf Architectural Shelf Architectural

ElementsElements

MARGINCOMPLEX

PROGRADING MARGINPROGRADING MARGIN

SHELFCOMPLEX


STACKESTACKEDD

BEDBEDCYCLESCYCLES

BED,BED,LITHOLOGY,LITHOLOGY,

SEDIMENTARYSEDIMENTARYSTRUCTURESSTRUCTURES

FAUNAFAUNA

ALLOCHEMSALLOCHEMSCEMENTATIONCEMENTATION& DIAGENESIS& DIAGENESIS


ONLAPPING MARGINONLAPPING MARGIN


Definition of element hierarchy Framework for systematic description & comparison of deposits of

a depositional setting (fluvial, deltaic, deepwater etc) Based on physical organization of strata (geometry) & the surfaces

bounding themGenetically-related stratigraphic elements form the hierarchyIndependent of type of settingApplicable at all scales & to all sedimentary systems

Purpose Analysis & comparison of the elements of similar depositional

systemsProvide the detailed character of a sequence and/or system tractNet to-gross, aspect ratio, & connectivityLithofacies type & aquifer/reservoir quality

ApplicationBetter defined depositional geometries and so depositional modelsMore accurate aquifer/resource assessmentOptimize strategy for depletion of aquifer/resource

Elements – Sequence Building Elements – Sequence Building BlocksBlocksElements – Sequence Building Elements – Sequence Building BlocksBlocks


History of Sequence History of Sequence StratigraphyStratigraphyHistory of Sequence History of Sequence StratigraphyStratigraphy

Sloss recognized intercontinental-Sloss recognized intercontinental-unconformitiesunconformities & & related them to eustasyrelated them to eustasy

Vail extrapolated eustatic signals to Vail extrapolated eustatic signals to seismic seismic sequence boundariessequence boundaries

Jervey’s simulations showed seismic sequences Jervey’s simulations showed seismic sequences product of product of cyclic sea levelcyclic sea level (base level) change (base level) change

Van Wagoner & Posamentier related Van Wagoner & Posamentier related unconformities, transgressive surfaces & maximum unconformities, transgressive surfaces & maximum flooding surfaces to boundaries of flooding surfaces to boundaries of system tractssystem tracts in in depositional sequences responding to sea level depositional sequences responding to sea level changechange

Hydrocarbon exploration models & production Hydrocarbon exploration models & production reservoir models use bounding surfaces, facies reservoir models use bounding surfaces, facies assemblages & assemblages & system tractssystem tracts as as templatestemplates for for depositional models & lithofacies depositional models & lithofacies geometry geometry predictionspredictions


Sloss Unconformities & Sloss Unconformities & EustasyEustasySloss Unconformities & Sloss Unconformities & EustasyEustasy

After Lowell ThwaiteAfter Lowell Thwaite


1st Seismic Sequence 1st Seismic Sequence InterpretationInterpretation

1st Seismic Sequence 1st Seismic Sequence InterpretationInterpretation

Vail et al, 1976Vail et al, 1976 Vail et al, 1976Vail et al, 1976

Mesozoic through Tertiary of Offshore MoroccoMesozoic through Tertiary of Offshore Morocco


'Depositional' sequence Vail'Depositional' sequence Vail 'Depositional' sequence Vail'Depositional' sequence Vail

JerveyJerveyPosmentierPosmentierVan WagonerVan Wagoner


Sequence stratigraphySequence stratigraphySequence stratigraphySequence stratigraphy Analytical protocol Analytical protocol marries rules of thumbmarries rules of thumb

(heuristics) (heuristics) to conceptual modelsto conceptual models Interprets general depositional setting of Interprets general depositional setting of

layered clastic & carbonate sedimentary layered clastic & carbonate sedimentary stratastrata

Models developed to interpret variety of Models developed to interpret variety of datasets datasets

Work best with combination of outcrop, core, Work best with combination of outcrop, core, well log, & seismic datawell log, & seismic dataMay work with two or more of these data May work with two or more of these data sources but are least reliable for a single data sources but are least reliable for a single data sourcesource

Local differences in depositional processes, Local differences in depositional processes, topography, and tectonics and, base level topography, and tectonics and, base level position, mean a model more appropriate position, mean a model more appropriate to one setting, than others? to one setting, than others?


Sequence Stratigraphy’s Sequence Stratigraphy’s Fuzzy RulesFuzzy RulesSequence Stratigraphy’s Sequence Stratigraphy’s Fuzzy RulesFuzzy Rules Lithofacies geometries & confining surfaces Lithofacies geometries & confining surfaces

transgress timetransgress time Different geometries for a specific time Different geometries for a specific time

interval interval Local variations in rates & direction of tectonic Local variations in rates & direction of tectonic movement movement

Local rates of sediment supply & accumulation Local rates of sediment supply & accumulation Not all erosional or depositional surfaces are Not all erosional or depositional surfaces are

product of base level changeproduct of base level change

Depositional models Depositional models successfully predictsuccessfully predict lithofacies geometry for exploration & lithofacies geometry for exploration & reservoirs reservoirs Depositional model is refined as data Depositional model is refined as data base growsbase grows


Sequence stratigraphic Sequence stratigraphic analysisanalysisSequence stratigraphic Sequence stratigraphic analysisanalysis

Strata deposited in Strata deposited in orderorder Surfaces subdivide strata into packages of beds Surfaces subdivide strata into packages of beds

with with common depositional origincommon depositional origin Geometric arrangement of strata & packages of Geometric arrangement of strata & packages of

strata reflectstrata reflectBasin Basin fillingfillingErosionalErosional events events

Commonly sequence stratigraphiy applied to Commonly sequence stratigraphiy applied to sediment accumulation at sediment accumulation at basin marginsbasin margins in in continental, marginal marine, and/or down-continental, marginal marine, and/or down-slope settingsslope settings

Fill accumulates either as: Fill accumulates either as: UnconfinedUnconfined fill over these settings fill over these settingsConfinedConfined within erosional down-cut topography within erosional down-cut topography

Fundamental to sequence stratigraphic analysis:Fundamental to sequence stratigraphic analysis:


Unconfined geometric Unconfined geometric architecturearchitectureUnconfined geometric Unconfined geometric architecturearchitecture

AggradingAggrading (lie above one another (lie above one another vertically)vertically)

ProgradingPrograding (inclined in order over (inclined in order over and beside one another in a seaward and beside one another in a seaward direction)direction)

RetrogradingRetrograding (inclined in order over (inclined in order over & beside one another in a landward & beside one another in a landward direction)direction)

Stacked layers tend to have Stacked layers tend to have threethreebasic patternsbasic patterns::


Stacking Patterns - Stacking Patterns - UnconfinedUnconfinedStacking Patterns - Stacking Patterns - UnconfinedUnconfined

After Van Wagoner


Confined geometric Confined geometric architecturearchitectureConfined geometric Confined geometric architecturearchitecture

OrganizedOrganized offset bodies and/or offset bodies and/or Randomly ordered Randomly ordered disorganizeddisorganized

offset bodiesoffset bodies

FillFill post post erosional down-cuttingerosional down-cutting expressed by a geometric expressed by a geometric architecture of stacked layers in architecture of stacked layers in either succession ofeither succession of ::


Confined Sedimentary Fill - Confined Sedimentary Fill - ChannelsChannelsConfined Sedimentary Fill - Confined Sedimentary Fill - ChannelsChannels


Stacking Pattern Rules & Stacking Pattern Rules & Problems Problems Stacking Pattern Rules & Stacking Pattern Rules & Problems Problems

End member stratal stacking patterns End member stratal stacking patterns reflect interplay of reflect interplay of accommodationaccommodation (space available for sediments to fill) & (space available for sediments to fill) & rates of sediment rates of sediment accumulationaccumulation

Local vagaries in Local vagaries in Depositional Depositional processesprocessesTopographyTopographyTectonicsTectonics & so base level position & so base level position

mean mean stacking stylesstacking styles of geometry may of geometry may mergemerge with one another but are tied to with one another but are tied to system tractssystem tracts


Stacking, Surfaces & System Stacking, Surfaces & System tracts!tracts!Stacking, Surfaces & System Stacking, Surfaces & System tracts!tracts!

LowstandLowstand - Progradation-to-aggradational - Progradation-to-aggradational (PA)(PA)

TransgressionTransgression - Retrogradational - Retrogradational geometries (R), geometries (R),

HighstandHighstand - Aggradational-to-progradation - Aggradational-to-progradation geometries (AP) system tracts (Van geometries (AP) system tracts (Van Wagoner et al., 1988; Neil and Abreu, 2008)Wagoner et al., 1988; Neil and Abreu, 2008)

As many as five system tracts recognized but As many as five system tracts recognized but above three are most commonly usedabove three are most commonly used

Geometric architecture of stacked Geometric architecture of stacked layers are inferred to be related to layers are inferred to be related to eustatic eventseustatic events ::


System Tracts - ReviewedSystem Tracts - Reviewed System Tracts - ReviewedSystem Tracts - Reviewed


System Tracts - System Tracts - UnconfinedUnconfinedSystem Tracts - System Tracts - UnconfinedUnconfined

System tracts defined by: System tracts defined by: Bounding surfacesBounding surfacesPosition within a sequencePosition within a sequenceGeometric stacking pattern Geometric stacking pattern

LowstandLowstand - Progradation-to-aggradational (PA) - Progradation-to-aggradational (PA) TransgressionTransgression - Retrogradational geometries - Retrogradational geometries

(R), (R), HighstandHighstand - Aggradational-to-progradation - Aggradational-to-progradation

geometries (AP) system tracts (Van Wagoner et geometries (AP) system tracts (Van Wagoner et al., 1988; Neil and Abreu, 2008)al., 1988; Neil and Abreu, 2008)

As many as five system tracts recognized but As many as five system tracts recognized but above three are most commonly usedabove three are most commonly used

3-D facies assemblages of common genetic 3-D facies assemblages of common genetic origin with unconfined geometric architecture origin with unconfined geometric architecture are interpreted to form during phases of are interpreted to form during phases of relative sea-level cycle (Posamentier, et al, relative sea-level cycle (Posamentier, et al, 1988)1988)


Surfaces, System tracts & Surfaces, System tracts & SequencesSequencesSurfaces, System tracts & Surfaces, System tracts & SequencesSequences

System tracts are inferred to be System tracts are inferred to be related to accommodation related to accommodation generation and fill. This relationship generation and fill. This relationship is explained using conceptual is explained using conceptual modelsmodels

Role of Role of conceptualconceptual depositional depositional modelsmodels::


Bounding SurfacesBounding SurfacesBounding SurfacesBounding Surfaces

Maximum Flooding SurfacesMaximum Flooding Surfaces (MFS) (MFS) Transgressive SurfacesTransgressive Surfaces (TS) (maximum (TS) (maximum

regressive surfaces & transgressive regressive surfaces & transgressive ravinement surfaces)ravinement surfaces)

Sequence BoundariesSequence Boundaries (SB) (subaerial (SB) (subaerial unconformities, regressive surfaces of unconformities, regressive surfaces of marine erosion & correlative marine erosion & correlative conformities).conformities).

Identification & interpretation of bounding Identification & interpretation of bounding surfaces that separate layered clastic and surfaces that separate layered clastic and carbonate sedimentary strata into genetically carbonate sedimentary strata into genetically related packages, system tracts, a key to related packages, system tracts, a key to Sequence StratigraphySequence Stratigraphy


Conceptual ModelsConceptual ModelsConceptual ModelsConceptual Models

'Depositional''Depositional' sequence of Vail et al 1971 sequence of Vail et al 1971 'Genetic Stratigraphic''Genetic Stratigraphic' sequence model of sequence model of

Galloway, 1989Galloway, 1989 'Transgressive-Regressive''Transgressive-Regressive' (T-R) (T-R)

sequence model of Embry and sequence model of Embry and Johannessen, 1992Johannessen, 1992

Three conceptual models commonly used Three conceptual models commonly used in sequence stratigraphy are separated in sequence stratigraphy are separated from each other on basis of bounding & from each other on basis of bounding & subdividing boundaries of subdividing boundaries of system tractssystem tracts::


'Depositional' Sequence (Vail et 'Depositional' Sequence (Vail et al 1971)al 1971)'Depositional' Sequence (Vail et 'Depositional' Sequence (Vail et al 1971)al 1971)

Bounded by subaerial unconformities & Bounded by subaerial unconformities & marine correlative conformitiesmarine correlative conformities

Bounding surface assumed genetically Bounding surface assumed genetically connected with stratigraphic hiatus connected with stratigraphic hiatus associated with subaerial unconformity associated with subaerial unconformity that is progressively younger in seaward that is progressively younger in seaward directiondirection

No matter systems-tract terminology used No matter systems-tract terminology used bounding surfaces of this sequence bounding surfaces of this sequence enclose:enclose:

Forced regressiveForced regressiveNormal regressive (lowstand and highstand) Normal regressive (lowstand and highstand) Transgressive sedimentary packagesTransgressive sedimentary packages


'Genetic Stratigraphic' 'Genetic Stratigraphic' Sequence Galloway, 1989Sequence Galloway, 1989

'Genetic Stratigraphic' 'Genetic Stratigraphic' Sequence Galloway, 1989Sequence Galloway, 1989 Bounded by maximum flooding surfaces.Bounded by maximum flooding surfaces. These surfaces interpreted to form as These surfaces interpreted to form as

sea level rises rapidly, sediment supply sea level rises rapidly, sediment supply slows & organic matter accumulates slows & organic matter accumulates sequestering radioactive materialssequestering radioactive materials

Sequence enclosesSequence enclosesForced regressive depositsForced regressive depositsNormal regressive (lowstand and highstand) Normal regressive (lowstand and highstand) depositsdepositsTransgressive depositsTransgressive deposits


'Transgressive-Regressive' (T-R) 'Transgressive-Regressive' (T-R) sequence (Embry & Johannessen, sequence (Embry & Johannessen, 1992)1992)

'Transgressive-Regressive' (T-R) 'Transgressive-Regressive' (T-R) sequence (Embry & Johannessen, sequence (Embry & Johannessen, 1992)1992)

Composite sequence boundary Composite sequence boundary includes subaerial unconformity & includes subaerial unconformity & marine portion of maximum marine portion of maximum regressive surfaceregressive surface

‘‘Normal' & 'forced' regressive Normal' & 'forced' regressive deposits are included within the deposits are included within the 'regressive systems tract''regressive systems tract'


Boundaries & Conceptual Boundaries & Conceptual ModelsModelsBoundaries & Conceptual Boundaries & Conceptual ModelsModels

After Catuneanu, After Catuneanu,

20072007 After Catuneanu, After Catuneanu,

20072007


SequenceSequenceStratigrapStratigrap

hyhyModelModelTreeTree

SequenceSequenceStratigrapStratigrap

hyhyModelModelTreeTree

After Catuneanu, After Catuneanu,

20022002 After Catuneanu, After Catuneanu,

20022002


Application & nomenclature of Application & nomenclature of conceptual models subject to conceptual models subject to debatedebate

Application & nomenclature of Application & nomenclature of conceptual models subject to conceptual models subject to debatedebate

Nomenclature of systems tracts & sequence Nomenclature of systems tracts & sequence stratigraphic surfacesstratigraphic surfaces

Surfaces that should be ranked as 'sequence boundary‘Surfaces that should be ranked as 'sequence boundary‘ Framework of surfaces, systems tracts, selection of Framework of surfaces, systems tracts, selection of

sequence boundaries may vary with approach, available sequence boundaries may vary with approach, available data sets, & depositional settingdata sets, & depositional setting

Good news!!Good news!! Sequence stratigraphic method determines depositional Sequence stratigraphic method determines depositional

setting of sectionsetting of section Identification of genetic units & bounding surfaces Identification of genetic units & bounding surfaces

mostly model independent. mostly model independent. For both non-marine and marine systems, no matter For both non-marine and marine systems, no matter

characterization of 'sequence boundary', these characterization of 'sequence boundary', these boundaries envelope sedimentary section as through-boundaries envelope sedimentary section as through-going physical surface from basin margin to depocentergoing physical surface from basin margin to depocenter


CaveatsCaveatsCaveatsCaveats Sequence stratigraphic surfaces serve, Sequence stratigraphic surfaces serve, at least at least

in partin part, as boundaries between different , as boundaries between different genetic types of depositgenetic types of deposit

NotNot all data lend themselves to identification all data lend themselves to identification of all sequence stratigraphic surfacesof all sequence stratigraphic surfaces

Not all sequence stratigraphic surfaces are Not all sequence stratigraphic surfaces are present in every depositional sectionpresent in every depositional section

Depositional settings of Depositional settings of nearshorenearshore to just to just offshoreoffshore generate an generate an arrayarray of depositional and of depositional and erosional surfaces, many of incorporated into erosional surfaces, many of incorporated into sequence stratigraphy sequence stratigraphy

In contrast, within either In contrast, within either fluvialfluvial and/or and/or deep-deep-waterwater systems, conditions favor formation of systems, conditions favor formation of fewer key bounding sequence stratigraphic fewer key bounding sequence stratigraphic surfacessurfaces


Why codify ‘rules’ for sequence Why codify ‘rules’ for sequence stratigraphic nomenclature?stratigraphic nomenclature?

We use We use common termscommon terms and know their and know their meaningmeaning

Have a Have a standard hierarchystandard hierarchy of subdivisions of subdivisions Have a Have a uniformuniform methodology methodology GuidanceGuidance for revision for revision Teaching resourceTeaching resource: each new generation of : each new generation of

students & practitioners have a common students & practitioners have a common understandingunderstanding


Terms to DefineTerms to DefineTerms to DefineTerms to Define SurfacesSurfaces

Separate layered clastic and carbonate Separate layered clastic and carbonate sedimentary strata into genetically related sedimentary strata into genetically related packages, system tractspackages, system tracts

System TractSystem TractSpecific three-dimensional facies assemblages of Specific three-dimensional facies assemblages of common genetic origin, associated with common genetic origin, associated with unconfined geometric architecture & interpreted unconfined geometric architecture & interpreted as formed during phases of a relative sea-level as formed during phases of a relative sea-level cyclecycle

Conceptual ModelsConceptual ModelsExplains configuration of surfaces and geometries Explains configuration of surfaces and geometries that occur in layered sedimentary record in terms that occur in layered sedimentary record in terms of:of:

Basinal settingBasinal settingRates of sediment supply & erosion (accumulation)Rates of sediment supply & erosion (accumulation)EustasyEustasyTectonic movementTectonic movement


Terms to Define - SurfacesTerms to Define - SurfacesTerms to Define - SurfacesTerms to Define - Surfaces

Subaerial unconformitySubaerial unconformity Correlative conformity (sensu Posamentier, Correlative conformity (sensu Posamentier,

and sensu Hunt and Tucker; the former and sensu Hunt and Tucker; the former have renamend Posamentier’s CC as the have renamend Posamentier’s CC as the “basal surface of forced regression”). (Two “basal surface of forced regression”). (Two different surfaces).different surfaces).

Regressive surface of marine erosion Regressive surface of marine erosion Maximum regressive surface Maximum regressive surface Maximum flooding surface Maximum flooding surface Transgressive ravinement surfacesTransgressive ravinement surfaces

Separate layered clastic & carbonate Separate layered clastic & carbonate sedimentary strata into genetically related sedimentary strata into genetically related packages, or system tractspackages, or system tracts


Terms to Define – Systems Terms to Define – Systems TractsTractsTerms to Define – Systems Terms to Define – Systems TractsTracts

Falling Stage Systems Tract (FSST) Falling Stage Systems Tract (FSST) Lowstand Systems Tract (LST) Lowstand Systems Tract (LST) Transgressive Systems Tract (TST)Transgressive Systems Tract (TST) Highstand Systems Tract (HST) Highstand Systems Tract (HST) Regressive System TractRegressive System Tract Low-accommodation systems TractLow-accommodation systems Tract High-accommodation Systems TractHigh-accommodation Systems Tract Forced regressionForced regression Normal regressionNormal regression TransgressionTransgression

Specific three-dimensional facies assemblages of Specific three-dimensional facies assemblages of common genetic origin, associated with unconfined common genetic origin, associated with unconfined geometric architecture & interpreted as formed during geometric architecture & interpreted as formed during phases of a relative sea-level cyclephases of a relative sea-level cycle


Terms to Define – Conceptual Terms to Define – Conceptual ModelsModelsTerms to Define – Conceptual Terms to Define – Conceptual ModelsModels

Depositional sequence modelDepositional sequence model Genetic Stratigraphic sequence modelGenetic Stratigraphic sequence model Transgressive-Regressive sequence Transgressive-Regressive sequence

modelmodel

Models that explain surfaces & geometries Models that explain surfaces & geometries of layered sediments in terms of basinal of layered sediments in terms of basinal setting, rates of supply & erosion setting, rates of supply & erosion (accumulation), eustasy, and tectonics(accumulation), eustasy, and tectonics


Definitions – Points to Definitions – Points to considerconsiderDefinitions – Points to Definitions – Points to considerconsider

DefinitionDefinition Alternate termsAlternate terms Origin of FeatureOrigin of Feature Absolute time or Fuzzy time significance if Absolute time or Fuzzy time significance if

any?any?


"What's in a "What's in a name? That which name? That which we call a rose. By we call a rose. By any other name any other name would smell as would smell as sweet.“sweet.“

Shakespeare's Shakespeare's Romeo and Juliet (IIRomeo and Juliet (II, ii, 1-2), ii, 1-2)

"What's in a "What's in a name? That which name? That which we call a rose. By we call a rose. By any other name any other name would smell as would smell as sweet.“sweet.“

Shakespeare's Shakespeare's Romeo and Juliet (IIRomeo and Juliet (II, ii, 1-2), ii, 1-2)

WHAT, YOU THINKWHAT, YOU THINKI’M AN IDIOT?I’M AN IDIOT?OF COURSE I OF COURSE I WROTE DOWN WROTE DOWN WHAT WENT WHAT WENT WHERE. WHERE. OH….. WAIT…… IS OH….. WAIT…… IS THAT AN “H” OR THAT AN “H” OR AN “I”AN “I”


Sequence Stratigraphy Sequence Stratigraphy The fundamental key to sequence stratigraphic The fundamental key to sequence stratigraphic interpretation is the interpretation is the surfacessurfaces that subdivide the that subdivide the sedimentary section. sedimentary section. Unfortunately the Unfortunately the nomenclaturenomenclature of each of these of each of these sequence stratigraphic surfaces is constantly sequence stratigraphic surfaces is constantly changingchanging asas our understanding of sedimentary systems & their our understanding of sedimentary systems & their interpretation improvesinterpretation improves Though changes in Though changes in nomenclaturenomenclature are well are well intentioned they add to the confusion to a scientific intentioned they add to the confusion to a scientific methodology that is already methodology that is already overlaid with complex overlaid with complex multi-syllable terminologymulti-syllable terminology A surface can be given a name that has been used A surface can be given a name that has been used before for a different surface. The innocent, not before for a different surface. The innocent, not knowing the terminology has been changed, may lack knowing the terminology has been changed, may lack understanding of the reason for the change, & feel understanding of the reason for the change, & feel that they are going that they are going stark raving madstark raving mad


Sequence Stratigraphy – Sequence Stratigraphy – ConclusionsConclusionsSequence Stratigraphy – Sequence Stratigraphy – ConclusionsConclusions

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

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

This template is used to predict the extent This template is used to predict the extent of sedimentary facies geometry, lithologic of sedimentary facies geometry, lithologic character, grain size, sorting & reservoir character, grain size, sorting & reservoir qualityquality


Which way now?Which way now?Which way now?Which way now?Paul Dimitri Krynine’s alleged mantra was Paul Dimitri Krynine’s alleged mantra was

that:that:

““Stratigraphy is the triumph of Stratigraphy is the triumph of terminology over common sense“terminology over common sense“

Our collective hope is to circumvent this Our collective hope is to circumvent this cynical position & propose a more cynical position & propose a more consistent & practical set of terminology!consistent & practical set of terminology!


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