Clastic depositional system

“Clastic Hierarchies”Christopher G. St. C. Kendall

Clastic Hierarchies and EustasyClastic Hierarchies and Eustasy

Spring 2005

Professor Christopher G. St. C. KendallProfessor Christopher G. St. C. [email protected] [email protected]

777.2410777.2410

Clastic Depositional SystemsClastic Depositional Systems

Their Response Their Response to to

Base Level ChangeBase Level Change

Based, in part, on classroom lectures Based, in part, on classroom lectures by David Barbeau & Chris Kendallby David Barbeau & Chris Kendall


Lecture Series OverviewLecture Series Overview Sequence stratigraphy & stratigraphic surfacesSequence stratigraphy & stratigraphic surfaces 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 level and Clastic system response to changing sea level and

rates of sedimentation - with movierates of sedimentation - with movie Carbonate systems response to changing sea Carbonate systems response to changing sea

level and rates of sedimentation - with movie level and rates of sedimentation - with movie Exercises – Sequence stratigraphy of carbonates Exercises – Sequence stratigraphy of carbonates

and clastics from chronostratigraphy, seismic, and clastics from chronostratigraphy, seismic, outcrop and well log characteroutcrop and well log character

Sedimentary rocks are the Sedimentary rocks are the product of the generation, product of the generation, transport, deposition, and transport, deposition, and diagenesis of detritus and diagenesis of detritus and solutes derived from pre-existing solutes derived from pre-existing rocks.rocks.

Sedimentary rocks are the Sedimentary rocks are the product of the creation, transport, product of the creation, transport, depositiondeposition, and diagenesis of , and diagenesis of detritus and solutes derived from detritus and solutes derived from pre-existing rocks.pre-existing rocks.



Depositional SystemsDepositional Systems depositional systemdepositional system:: assemblage of multiple process-related assemblage of multiple process-related

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

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

NBNB depositional systems are: depositional systems are:modern featuresmodern featuresused to interpret ancient sedimentary successionsused to interpret ancient sedimentary successions


Types of Depositional SystemsTypes of Depositional Systems

marinemarine ocean, sea ocean, sea

transitionaltransitional part land, part ocean part land, part ocean

terrestrialterrestrial land land


Clastic Depositional SystemsClastic Depositional SystemsTerrestrialTerrestrial

Transitional

TransitionalMarineMarine



Transitional




Transitional






Characteristics of Clastic SystemCharacteristics of Clastic System Critical stratigraphic signals of system?Critical stratigraphic signals of system? Geomorphologic & tectonic setting Geomorphologic & tectonic setting Dominant sedimentary processesDominant sedimentary processes FaciesFacies

Subdividing surfacesSubdividing surfacesLithologyLithologySedimentary structuresSedimentary structuresGeometries – Confined versus open Geometries – Confined versus open Fauna & floraFauna & flora












Marine Depositional SystemsMarine Depositional Systems shallow/nearshoreshallow/nearshore

tide-dominatedtide-dominatedwave-dominatedwave-dominatedreefreef

shelf/platformshelf/platformcarbonatecarbonateclasticclastic

deep marinedeep marinedeep sea fansdeep sea fanspelagicpelagic


Marine Depositional SystemsMarine Depositional Systems wave-dominated coastswave-dominated coasts tide-dominated coaststide-dominated coasts fluvial-dominated coasts (deltas)fluvial-dominated coasts (deltas) carbonate reefscarbonate reefs clastic shelves & platformsclastic shelves & platforms carbonate shelves & platformscarbonate shelves & platforms deepwater fansdeepwater fans pelagic abyssal plainspelagic abyssal plains


Coastal Depositional SystemsCoastal Depositional Systems Form proximal to shorelinesForm proximal to shorelines Geographically narrow, geologically importantGeographically narrow, geologically important Fluid flow transport and depositionFluid flow transport and deposition

Surface wavesSurface wavesTidal waves (not tsunami!)Tidal waves (not tsunami!)Fluvial inputFluvial input

Grain-size decreases with deeper water Grain-size decreases with deeper water Onshore, offshore & longshore sediment transport Onshore, offshore & longshore sediment transport

importantimportant Net sediment input (often from rivers) often leads to Net sediment input (often from rivers) often leads to

progradationalprogradational geometries geometries Important for tracking sea-level changesImportant for tracking sea-level changes


Coast TypesCoast Types

Dalrymple et al, 1992Dalrymple et al, 1992



Dalrymple et al, 1992


Tidal Range and Coastal MorphologyTidal Range and Coastal Morphology

Hayes, 1979Hayes, 1979


CoastCoastTypesTypes


Marine Depositional SystemsMarine Depositional Systems wave-dominated coastswave-dominated coasts tide-dominated coaststide-dominated coasts fluvial-dominated coasts (deltas)fluvial-dominated coasts (deltas) carbonate reefscarbonate reefs clastic shelves & platformsclastic shelves & platforms carbonate shelves & platformscarbonate shelves & platforms deepwater fansdeepwater fans pelagic abyssal plainspelagic abyssal plains


Waves & Wave PeriodsWaves & Wave Periods


Characteristics of Beach SystemsCharacteristics of Beach Systems Sediments coarsen upward from marine shalesSediments coarsen upward from marine shales Linear sand bodies parallel to basin margin, serrated margins landward Linear sand bodies parallel to basin margin, serrated margins landward Formed by a mix of waves and tidal currentsFormed by a mix of waves and tidal currents FaciesFacies

Subdivided erosion surfaces formed during Subdivided erosion surfaces formed during – Dropping in base levelDropping in base level

Local channelsLocal channels– Rising in base levelRising in base level

Wells sorted and rounded pure quartz arenites commonWells sorted and rounded pure quartz arenites commonSedimentary structures Sedimentary structures

– Offshore hummocky wavy beddingOffshore hummocky wavy bedding– Nearshore cut and fillNearshore cut and fill– Gently seaward dipping thin parallel beds Gently seaward dipping thin parallel beds

Geometries Geometries – Confined incised channelsConfined incised channels– Open linear sheets parallel to shore Open linear sheets parallel to shore

Fauna & floraFauna & flora– Marine fauna at base of units Marine fauna at base of units – Terrestrial flora at crest of units Terrestrial flora at crest of units


Vertical stacking of shore line sedimentsVertical stacking of shore line sediments




Beach Face - South Carolina ForeshoreBeach Face - South Carolina Foreshore

Note High Energy Planar BedsNote High Energy Planar Beds

Photo: G. Voulgaris


Trough Cross-bed Current RipplesTrough Cross-bed Current Ripples

Ordovician – Near WinchesterOrdovician – Near WinchesterKentuckyKentucky


Offshore Coastal Profile - HummockyOffshore Coastal Profile - Hummocky


Coastal ProfileCoastal Profile


GeomorphologyGeomorphologyof Coastof Coast


Coastal MorphologyCoastal Morphology



Coastal Profile and LithofaciesCoastal Profile and Lithofacies


Coastal Lithofacies & ArchitectureCoastal Lithofacies & Architecture

Aigner & Reineck, 1982


CoastalCoastalLithofaciesLithofacies

Reineck & Singh, 1980


Walker, 1984Walker, 1984

ProgradationProgradation TransgressionTransgression InletInlet

Coastal LithofaciesCoastal Lithofacies


Hayes, 1979Hayes, 1979


Hubbard et al., 1979Hubbard et al., 1979

Tide Versus Wave DominationTide Versus Wave Domination



Coastal MorphologyCoastal Morphology


Wave Dominated - Texan CoastWave Dominated - Texan Coast

Note Storm WashoverNote Storm WashoverSerrated Back BarrierSerrated Back Barrier



Note Storm Washover

Note Storm Washover

Serrated Back Barrier




Note Storm Washover

Note Storm Washover





Note Storm WashoverNote Storm WashoverSerrated Back BarrierSerrated Back Barrier

PennsylvanianPennsylvanian Wave Dominated CoastWave Dominated Coast

Note Storm WashoverNote Storm WashoverOn a Back BarrierOn a Back Barrier




Chenier Coast – Gulf of CarpentariaChenier Coast – Gulf of Carpentaria

Note Channels ReworkingNote Channels ReworkingChenier PlainChenier Plain

Note Channels ReworkingNote Channels ReworkingBarrier IslandsBarrier Islands


Delta Mouth Bar - KentuckyDelta Mouth Bar - Kentucky

Note Incised Surface Of Reworked BarNote Incised Surface Of Reworked Bar


Tidal, Storm or Tsunami ChannelTidal, Storm or Tsunami Channel

Note Incised Surface Beneath ChannelNote Incised Surface Beneath Channel


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

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

these surfaces these surfaces


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

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

these surfaces these surfaces


Beach Ridges: St. Phillips Island, SCBeach Ridges: St. Phillips Island, SC


Progradation & Transgressive ArchitecturesProgradation & Transgressive Architectures

Kraft & John, 1979

“Clastic Hierarchies”Christopher G. St. C. Kendall Reading, 1986

Sea-Level Changes Sea-Level Changes


Visser, 1980

Tidal BundlesTidal Bundles


Bedforms Bedforms Current RipplesCurrent Ripples

Sand in mud m

atrix

Sand in mud m

atrix

Sand predominates

Sand predominates

Sand & Mud 50/50

Sand & Mud 50/50


Asymmetric Current RipplesAsymmetric Current Ripples

Upper Mississippian – Pennington FormationUpper Mississippian – Pennington FormationPound GapPound Gap


Base Level Change on CoastBase Level Change on Coast


Tidal GeomorphologyTidal Geomorphology

Kraft et al, 1987


Transitional Depositional Transitional Depositional SystemsSystems

EstuariesEstuariesDeltasDeltas


Characteristics of Estuary SystemsCharacteristics of Estuary Systems Sediments coarsen upward from marine shalesSediments coarsen upward from marine shales Sand bodies perpendicular to basin margin, narrow landward Sand bodies perpendicular to basin margin, narrow landward Formed by a mix of tidal currents and occasional storm wavesFormed by a mix of tidal currents and occasional storm waves FaciesFacies



Wells sorted and rounded pure quartz arenites commonWells sorted and rounded pure quartz arenites commonSedimentary structures Sedimentary structures

– Offshore hummocky wavy beddingOffshore hummocky wavy bedding– Nearshore cut and fillNearshore cut and fill– Gently seaward dipping thin parallel beds Gently seaward dipping thin parallel beds

Geometries Geometries – Confined incised channelsConfined incised channels– Open linear sheets perpendicular and occasionally parallel to shore Open linear sheets perpendicular and occasionally parallel to shore



Estuarine LithofaciesEstuarine Lithofacies

Horne et al, 1978Horne et al, 1978




Marine Depositional SystemsMarine Depositional Systems Wave-dominated coastsWave-dominated coasts Tide-dominated coastsTide-dominated coasts Fluvial-dominated coasts (deltas)Fluvial-dominated coasts (deltas) Carbonate reefsCarbonate reefs Clastic shelves & platformsClastic shelves & platforms Carbonate shelves & platformsCarbonate shelves & platforms Deepwater fansDeepwater fans Pelagic abyssal plainsPelagic abyssal plains


Deltaic Depositional SystemsDeltaic Depositional Systems Form where rivers with large drainages meet standing Form where rivers with large drainages meet standing

water bodies (~basins)water bodies (~basins) Very large sediment fluxVery large sediment flux Fluid & gravity flow transport and depositionFluid & gravity flow transport and deposition

Surface wavesSurface wavesTidal waves (not tsunami!)Tidal waves (not tsunami!)Fluvial inputFluvial inputTurbidity currents & sub-aqueous debris flowsTurbidity currents & sub-aqueous debris flows

Net sediment input often leads to Net sediment input often leads to progradationalprogradational geometriesgeometries

Delta types depend on tidal range, wave climate, and Delta types depend on tidal range, wave climate, and composition and depths of water in river and basincomposition and depths of water in river and basin


Characteristics of Deltaic SystemsCharacteristics of Deltaic Systems Sediments coarsen upward from marine shalesSediments coarsen upward from marine shales Sand bodies form tongues perpendicular to basin marginSand bodies form tongues perpendicular to basin margin Formed by a mix of fluvial input, tidal currents and storm wavesFormed by a mix of fluvial input, tidal currents and storm waves FaciesFacies



Poorly sorted and irregular litharenites commonPoorly sorted and irregular litharenites commonSedimentary structures Sedimentary structures

– Offshore laminated to hummocky wavy beddingOffshore laminated to hummocky wavy bedding– Nearshore cut and fillNearshore cut and fill– Gently seaward dipping thin parallel beds Gently seaward dipping thin parallel beds

Geometries Geometries – Confined incised channelsConfined incised channels– Open linear sheets perpendicular and occasionally parallel to shore Open linear sheets perpendicular and occasionally parallel to shore




Dalrymple et al, 1992Dalrymple et al, 1992






Lena River Delta - RussiaLena River Delta - Russia


ShattShattal Arabal ArabDelta Delta


AtachafalyaAtachafalya Delta - USADelta - USA


AmazonAmazon Delta - BrazilDelta - Brazil


NileNile Delta - EgyptDelta - Egypt


Delta TypesDelta Types River-dominatedRiver-dominated

Small tidal range, weak storms and large Small tidal range, weak storms and large sediment flux build delta out into basinsediment flux build delta out into basin

Tide-dominatedTide-dominatedLarge tidal ranges dominate transport, Large tidal ranges dominate transport, deposition & geomorphologydeposition & geomorphology

Wave-dominatedWave-dominatedStrong and repeated storms rework delta Strong and repeated storms rework delta sedimentsediment


Delta ProcessesDelta Processes Depositional patterns and geomorphology Depositional patterns and geomorphology

depend on the relative dominance of three depend on the relative dominance of three competing processes at river mouths:competing processes at river mouths:

Inertia Inertia – River water River water – Basin waterBasin water

FrictionFriction– Water vs. substrateWater vs. substrate– Water vs. waterWater vs. water

BuoyancyBuoyancy


Delta ProcessesDelta ProcessesRelative influence of inertia, friction & buoyancy is a Relative influence of inertia, friction & buoyancy is a function of:function of: Density contrastsDensity contrasts

Homopycnal flow – equal density water bodies mixHomopycnal flow – equal density water bodies mixHyperpycnal flow – higher density sinks below ocean (Yellow)Hyperpycnal flow – higher density sinks below ocean (Yellow)Hypopycnal flow – lower density floats on ocean (Mississippi)Hypopycnal flow – lower density floats on ocean (Mississippi)

Concentration, grain size and suspended vs. bedload Concentration, grain size and suspended vs. bedload ratioratioWater depthsWater depths

Mouth Mouth BasinBasin

Water dischargeWater discharge Water inflow velocityWater inflow velocity


Delta ProcessesDelta Processes Inertia-dominated deltasInertia-dominated deltas

deep water, steep slopes, high river flow velocitydeep water, steep slopes, high river flow velocitymoderate sediment transport, large flow expansionmoderate sediment transport, large flow expansion

Friction-dominated deltasFriction-dominated deltasshallow water, low slopes, shallow water, low slopes, proximal sediment transport, large bars, limited flow proximal sediment transport, large bars, limited flow expansionexpansionhyperpycnal flow possiblehyperpycnal flow possible

Buoyancy-dominated deltasBuoyancy-dominated deltasdeep water, hypopycnal flow, large suspended loaddeep water, hypopycnal flow, large suspended loaddistant sediment transport, flow rafting distant sediment transport, flow rafting plumes plumes



Delta MorphologyDelta Morphology



River-Dominated DeltasRiver-Dominated Deltas


Lobe-SwitchingLobe-Switching


Inter-distributary baysInter-distributary bays


Mahakam River-Dominated DeltaMahakam River-Dominated Delta





Wave-dominated Grijalva DeltaWave-dominated Grijalva Delta


BramaputraBramaputra Delta - IndiaDelta - India


Tide-Dominated Niger DeltaTide-Dominated Niger Delta


Tide-Dominated Niger DeltaTide-Dominated Niger Delta


DeltaDeltaSuccessionsSuccessions


Delta SuccessionDelta Succession


Wave-DominatedWave-DominatedDelta SuccessionDelta Succession


Delta CollapseDelta Collapse


Delta Collapse Delta Collapse


Fan-DeltasFan-Deltas


Deltaic SuccessionDeltaic Succession











Marine Depositional SystemsMarine Depositional Systems

wave-dominated coastswave-dominated coasts tide-dominated coaststide-dominated coasts fluvial-dominated coasts (deltas)fluvial-dominated coasts (deltas) carbonate reefscarbonate reefs clastic shelves & platformsclastic shelves & platforms carbonate shelves & platformscarbonate shelves & platforms deepwater fansdeepwater fans pelagic abyssal plainspelagic abyssal plains


Deep SeaDeep SeaDepositional Depositional

SystemsSystems


Deep Sea Depositional SystemsDeep Sea Depositional Systems


Characteristics of Deepwater SystemsCharacteristics of Deepwater Systems Sediments fine upward from marine fansSediments fine upward from marine fans Sand bodies form lobes perpendicular to basin marginSand bodies form lobes perpendicular to basin margin Formed by a mix of fluvial input, and turbidite currentsFormed by a mix of fluvial input, and turbidite currents FaciesFacies

Subdivided erosion surfaces formed during Subdivided erosion surfaces formed during – Migrating fan lobe fillMigrating fan lobe fill– Dropping in base levelDropping in base level


Poor to well sorted litharenites commonPoor to well sorted litharenites commonSedimentary structures Sedimentary structures

– Fining upward cycles that coarsen up as depo-center of lobes migrateFining upward cycles that coarsen up as depo-center of lobes migrate– Up dip channel cut and fillUp dip channel cut and fill– Gently seaward dipping thin parallel lobate sheets Gently seaward dipping thin parallel lobate sheets

Geometries Geometries – Confined incised channelsConfined incised channels– Open lobate sheets perpendicular and occasionally parallel to shore Open lobate sheets perpendicular and occasionally parallel to shore

Fauna & floraFauna & flora– Restricted Marine fauna often in over bank shales Restricted Marine fauna often in over bank shales


Deep Sea Fan Depositional SystemsDeep Sea Fan Depositional Systems Form in the moderate to deep ocean, down-dip of Form in the moderate to deep ocean, down-dip of

submarine canyons and often deltassubmarine canyons and often deltas Large sediment flux, high sedimentation rate, large Large sediment flux, high sedimentation rate, large

areaarea Gravity flow transport and depositionGravity flow transport and deposition

turbidity currentsturbidity currentssubaqueous debris flowssubaqueous debris flowssuspension fall-outsuspension fall-out

Lobes and lobe-switching importantLobes and lobe-switching important Both coarse and fine grained sedimentBoth coarse and fine grained sediment Often well-sorted and normally gradedOften well-sorted and normally graded


Bengal Fan & Ganges-Brahmaputra DeltaBengal Fan & Ganges-Brahmaputra Delta


Submarine Canyons and Deep Sea FansSubmarine Canyons and Deep Sea Fans



Submarine CanyonsSubmarine Canyons



Submarine Canyons and Deep Sea Submarine Canyons and Deep Sea FansFans


Submarine Fan MorphologySubmarine Fan Morphology






SubmarineSubmarineFan TypesFan Types


Turbidity Currents Turbidity Currents Turbidites Turbidites


Gravity Flows: Turbidity CurrentsGravity Flows: Turbidity Currents


Turbidity Currents & Hemipelagic SedimentTurbidity Currents & Hemipelagic Sediment


Deep Water Fan DepositsDeep Water Fan Deposits


Deep Water Fan DepositsDeep Water Fan Deposits


TurbiditesTurbidites


Coarse-grained TurbiditesCoarse-grained Turbidites


Coarse-grained TurbiditesCoarse-grained Turbidites


TurbiditesTurbidites


Proximal TurbiditesProximal Turbidites


Distal TurbiditesDistal Turbidites


Soft-Sediment DeformationSoft-Sediment Deformation


Submarine ChannelsSubmarine Channels


Delaware Mountains – Basin FansDelaware Mountains – Basin Fans

Channel Sands

Channel Sands

Deepwater ChannelDeepwater Channel

Kendall PhotoKendall Photo


Brushy Canyon Group - Base of Slope Brushy Canyon Group - Base of Slope Permian BasinPermian Basin


Channel FillChannel FillTurbidites Turbidites


Brushy Canyon GroupBrushy Canyon Group - Base of Slope - - Base of Slope - Permian BasinPermian Basin

U.S. Highway 62-180 south of Guadalupe PassU.S. Highway 62-180 south of Guadalupe Pass

Margin of submarine fan channel incised Margin of submarine fan channel incised into "overbank". Channel fill with into "overbank". Channel fill with amalgamation as well as flowage & injection amalgamation as well as flowage & injection of sand into the surrounding strata of the of sand into the surrounding strata of the channel walls.channel walls.



Pelagic Depositional SystemsPelagic Depositional Systems Form in the open ocean or open (large) lakes and seasForm in the open ocean or open (large) lakes and seas Small sediment flux, very low sedimentation rateSmall sediment flux, very low sedimentation rate Suspended load current transport Suspended load current transport

Surface wavesSurface wavesTidal waves (not tsunami!)Tidal waves (not tsunami!)Fluvial inputFluvial inputTurbidity currents & sub-aqueous debris flowsTurbidity currents & sub-aqueous debris flows

Suspension fall-out deposition Suspension fall-out deposition Fine-grained (clay, mud and silt) depositionFine-grained (clay, mud and silt) deposition

CarbonatesCarbonatesSiliciclastic mudstonesSiliciclastic mudstones


Pelagic SedimentsPelagic Sediments


Deep Marine SedimentationDeep Marine Sedimentation


Pelagic SedimentsPelagic Sediments


Calcareous MicrofossilsCalcareous Microfossils


CCDCCD


Abyssal PlainsAbyssal Plains


Siliceous MicrofossilsSiliceous Microfossils


Siliceous Microfossils Siliceous Microfossils Chert Chert


Siliceous Microfossils Siliceous Microfossils Chert Chert


Aeolian DustAeolian Dust





http://toms.gsfc.nasa.gov/aerosols/images/dust021.gif


DropstonesDropstones







Terrestrial Depositional SystemsTerrestrial Depositional Systems

Alluvial Fan Alluvial Fan FluvialFluvial GlacialGlacial EolianEolian LacustrineLacustrine PlayaPlaya





Alluvial Fan System Characteristics Alluvial Fan System Characteristics Sediments fine upward within fan lobesSediments fine upward within fan lobes Sand bodies form lobes perpendicular to basin marginSand bodies form lobes perpendicular to basin margin Formed by a mix of fluvial input, and mass sediment movementFormed by a mix of fluvial input, and mass sediment movement FaciesFacies

Subdivided erosion surfaces formed during Subdivided erosion surfaces formed during – Migrating fan lobe fillMigrating fan lobe fill– Dropping in base levelDropping in base level


Poor to well sorted litharenite boulders, gravels and sands commonPoor to well sorted litharenite boulders, gravels and sands commonSedimentary structures Sedimentary structures

– Fining upward cycles that coarsen up as depo-center of lobes progrdesFining upward cycles that coarsen up as depo-center of lobes progrdes– Up dip channel cut and fillUp dip channel cut and fill– Gently seaward dipping thin parallel lobate sheets Gently seaward dipping thin parallel lobate sheets

Geometries Geometries – Confined incised channelsConfined incised channels– Open lobate sheets perpendicular and occasionally parallel to Mt front Open lobate sheets perpendicular and occasionally parallel to Mt front

Fauna & floraFauna & flora– Terrestrial flora can be common in over bank lobes Terrestrial flora can be common in over bank lobes


Alluvial Fan Depositional SystemsAlluvial Fan Depositional Systems Form upon exit of drainage basin from a mountain frontForm upon exit of drainage basin from a mountain front Mix of sediment gravity flow & fluid flow depositional Mix of sediment gravity flow & fluid flow depositional

processesprocessesDebris flowsDebris flowsHyperconcentrated flowsHyperconcentrated flowsFluvial channelsFluvial channelsSheetfloodsSheetfloods

Lobe-switching processes produce coneLobe-switching processes produce cone Radial sediment dispersalRadial sediment dispersal Decreasing grain size downslopeDecreasing grain size downslope



exit gorge

active lobes



Drainage & Depositional BasinsDrainage & Depositional Basins


Alluvial Fan ArchitectureAlluvial Fan Architecture

Spearing, 1974Spearing, 1974


Alluvial Fans Alluvial Fans

Blair & McPherson. 1994Blair & McPherson. 1994



Kelly & Olson, 1993Kelly & Olson, 1993


Alluvial and Fluvial FansAlluvial and Fluvial Fans ‘‘Stream-dominated’ Alluvial FansStream-dominated’ Alluvial Fans D = ~10 Km; S = 5-15D = ~10 Km; S = 5-15ºº

‘‘Gravity-flow’ Alluvial FansGravity-flow’ Alluvial Fans D = ~10 Km; S = 5-15D = ~10 Km; S = 5-15ºº

Talus ConesTalus Cones D < 1 Km; S = 10-30D < 1 Km; S = 10-30ºº

Fluvial MegafansFluvial Megafans D = 50 -100s Km; S < 1D = 50 -100s Km; S < 1ºº



Alluvial Fan StratigraphyAlluvial Fan Stratigraphy

Nemec & Steel, 1984Nemec & Steel, 1984





Stream-dominated AF StratigraphyStream-dominated AF Stratigraphy

Boothroyd, 1972Boothroyd, 1972


Gravity-Flow AF StratigraphyGravity-Flow AF Stratigraphy

Blair, 1987Blair, 1987



Gloppen & Steel, 1980Gloppen & Steel, 1980





Fluvial System Characteristics Fluvial System Characteristics Sediments fine upward within channel fillSediments fine upward within channel fill Sand bodies fine distally from channelsSand bodies fine distally from channels Formed by a mix of fluvial bedload, and fine suspended sedimentFormed by a mix of fluvial bedload, and fine suspended sediment FaciesFacies

Subdivided erosion surfaces formed during Subdivided erosion surfaces formed during – Migrating channel fillMigrating channel fill– Dropping in base levelDropping in base level


Poor to well sorted litharenite gravels, sands and shales commonPoor to well sorted litharenite gravels, sands and shales commonSedimentary structures Sedimentary structures

– Fining upward cycles that fill channelsFining upward cycles that fill channels– Up dip channel cut and fillUp dip channel cut and fill– Gently dipping thin parallel lobate sheets perpendicular to channelsGently dipping thin parallel lobate sheets perpendicular to channels

Geometries Geometries – Confined incised channelsConfined incised channels– Open lobate sheets perpendicular and occasionally parallel to channelsOpen lobate sheets perpendicular and occasionally parallel to channels

Fauna & floraFauna & flora– Terrestrial flora can be common in over bank sediments Terrestrial flora can be common in over bank sediments


Fluvial Depositional SystemsFluvial Depositional Systems Dominant conduit from regions of sediment Dominant conduit from regions of sediment

production (mountains) to sediment storage production (mountains) to sediment storage (oceans, basins)(oceans, basins)

Characterized by channel patternCharacterized by channel patternMeanderingMeanderingBraidedBraidedAnastomozingAnastomozing

Characterized by sediment loadCharacterized by sediment loadBedloadBedloadSuspended loadSuspended loadMixed loadMixed load

Unidirectional sediment dispersalUnidirectional sediment dispersal



Fluvial Channel PatternsFluvial Channel Patterns



Schumm & Khan, 1972Schumm & Khan, 1972


Meandering StreamsMeandering Streams


Meandering Fluvial SystemMeandering Fluvial System

Allen, 1964Allen, 1964


ThalwegsThalwegs


AvulsionAvulsion

Cross et al., 1989Cross et al., 1989


Meandering Fluvial ArchitectureMeandering Fluvial Architecture


Braided Fluvial ArchitectureBraided Fluvial Architecture

Nemec, 1992Nemec, 1992


Fluvial ChannelsFluvial Channels

HirstHirst, , 19911991


MaturityMaturity


Fluvial CharacterizationFluvial Characterization

Schumm, 1981Schumm, 1981



Orton & Reading, 1993Orton & Reading, 1993



fluvialfluvial alluvial fanalluvial fan glacialglacial eolianeolian lacustrinelacustrine playaplaya

GLACIERSGLACIERSAND AND GLACIATIONGLACIATION


Past Glacial PeriodsPast Glacial Periods Pre-Cambrian at end of Neoproterozoic eonPre-Cambrian at end of Neoproterozoic eon End of the OrdovicianEnd of the Ordovician Late Carboniferous (Pennsylvanian] Late Carboniferous (Pennsylvanian]

through Permianthrough Permian PleistocenePleistocene


Glacial PeriodsGlacial Periods


The Snowball EarthThe Snowball Earth

During last ice age max, 21,000 years ago, North During last ice age max, 21,000 years ago, North America & Europe covered by glaciers over 2 America & Europe covered by glaciers over 2 kilometers thick, sea level dropped 120 meters. kilometers thick, sea level dropped 120 meters. Global chill : land & sea ice covered 30 %t of Earth, Global chill : land & sea ice covered 30 %t of Earth, more than at other times in last 500 million yearsmore than at other times in last 500 million years

Near end of Neoproterozoic eon (1000-543 million Near end of Neoproterozoic eon (1000-543 million years ago), glaciation immediately preceded first years ago), glaciation immediately preceded first appearance of recognizable animal life some 600 appearance of recognizable animal life some 600 million years agomillion years ago


Paul Hoffman & Daniel Schrag - Paul Hoffman & Daniel Schrag - Snowball EarthSnowball Earth Sun abruptly cooled or Earth tilted on its axis or Sun abruptly cooled or Earth tilted on its axis or

experienced an orbital blip that reduced solar experienced an orbital blip that reduced solar warmth or carbon dioxide increased?warmth or carbon dioxide increased?

ice sheets covered continents & seas froze ice sheets covered continents & seas froze almost to equator, events that occurred at least almost to equator, events that occurred at least twice between 800 million & 550 million years twice between 800 million & 550 million years agoago

Each glacial period lasted millions of years & Each glacial period lasted millions of years & ended under extreme greenhouse conditions. ended under extreme greenhouse conditions. Climate shocks triggered evolution of Climate shocks triggered evolution of multicellular animal life, & challenge long-held multicellular animal life, & challenge long-held assumptions regarding the limits of global assumptions regarding the limits of global changechange


SnowballSnowballEarthEarth

-- Rocky cliffs Rocky cliffs

along along Namibia's Namibia's Skeleton Skeleton

Coast.Coast.


SnowballSnowballEarthEarth

-- Drop Drop

StonesStones



Glacial System CharacteristicsGlacial System Characteristics Signal extremes in local climate & sea level positionSignal extremes in local climate & sea level position Stratigraphic markers of glacial eventsStratigraphic markers of glacial events Source of Source of tillite (pebbles & larger fragments supported in tillite (pebbles & larger fragments supported in

fine-grained matrix ) deposited from glaciers. fine-grained matrix ) deposited from glaciers. Massive tillite inferred deposited below ice sheets or dropping Massive tillite inferred deposited below ice sheets or dropping from marine supported ice in submarine settingfrom marine supported ice in submarine settingBanded tillite may be deposited by ice sheetsBanded tillite may be deposited by ice sheets

Laminites common in lakes (Varve), Loess dust on landLaminites common in lakes (Varve), Loess dust on land Supraglacial & pro-glacial deposits with stratified Supraglacial & pro-glacial deposits with stratified

conglomerates & sandstoneconglomerates & sandstone U Shaped valleys & glacial striae U Shaped valleys & glacial striae Mountain glaciation could be source of much downslope Mountain glaciation could be source of much downslope

fluvial sedimentfluvial sediment


Simplified Glacial Systems signalsSimplified Glacial Systems signals Sediment signal a mix of:Sediment signal a mix of:

Glacial carried & dumped in morainesGlacial carried & dumped in morainesWater born fluvial sedimentWater born fluvial sedimentLacustrian varvesLacustrian varvesAeolian loessAeolian loess

Erosion: Erosion: U-shaped valleysU-shaped valleysEroded rock surfaceEroded rock surface– GroovedGrooved– Plucked Plucked – StriatedStriated

Base level: changes in sea level.Base level: changes in sea level.


Glacial Setting Glacial Setting

Develop where all of annual snow doesn’t melt away Develop where all of annual snow doesn’t melt away in warm seasonsin warm seasons

Polar regionsPolar regionsHeavy winter snowfall Heavy winter snowfall e.g. Washington Statee.g. Washington StateHigh elevations High elevations e.g. even equatore.g. even equator85% in Antarctica85% in Antarctica10% in Greenland10% in Greenland

Currently forms 10% of earths’s surface, Pleistocene Currently forms 10% of earths’s surface, Pleistocene reached 30%, but in Pre Cambrian could have reached 30%, but in Pre Cambrian could have reached 100%reached 100%


Adelie Penguins Taking a DiveAdelie Penguins Taking a Dive


Glacial ErosionGlacial Erosion Under glacierUnder glacier

Abrasion & pluckingAbrasion & pluckingBedrock polished & striatedBedrock polished & striatedRock flour washes out of glacierRock flour washes out of glacierPolishing and roundingPolishing and rounding

– ““Sheep Rocks”Sheep Rocks”

Striations- scratches & grooves on rockStriations- scratches & grooves on rock Above glacierAbove glacier

Frost wedging takes placeFrost wedging takes placeErosion by glaciers steepens slopesErosion by glaciers steepens slopes


Roche Moutone – Ice Sheet PluckingRoche Moutone – Ice Sheet Plucking


Glacial Scarring Glacial Scarring Of Bedrock Of Bedrock

--Findelen Findelen

GlacierGlacierSwitzerlandSwitzerland

--MatterhornMatterhorn

In In BackgroundBackground


Glacial SedimentsGlacial Sediments Facies of continental glacial settings Facies of continental glacial settings

Grounded Ice FaciesGrounded Ice FaciesGlaciofluvial facies Glaciofluvial facies Glacial lacustrine faciesGlacial lacustrine facies

– Facies of proglacial lakesFacies of proglacial lakes– Facies of periglacial lakesFacies of periglacial lakes

Cold-climate periglacial faciesCold-climate periglacial facies

Facies of marine glacial settingsFacies of marine glacial settingsProximal faciesProximal faciesContinental Shelf faciesContinental Shelf faciesDeepwater faciesDeepwater facies


Glacial DepositionGlacial Deposition TillTill

Unsorted debris in fine matrixUnsorted debris in fine matrix ErraticErratic Moraine- body of tillMoraine- body of till

Lateral MoraineLateral MoraineMedial Moraine- where tributaries joinMedial Moraine- where tributaries joinEnd moraine-End moraine-

– Terminal Terminal – RecessionalRecessional

Ground moraineGround moraineDrumlinDrumlin



Twenty Mile Medial MoraineTwenty Mile Medial Moraine


Robinson Tumbling Glacier Brit. ColumbiaRobinson Tumbling Glacier Brit. Columbia


Ground and End MorainesGround and End Moraines


GlacialGlacialLakesLakes

--IrelandIreland


Glacial SedimentsGlacial Sediments


VarvesVarves


Glaciation Subdividing SurfacesGlaciation Subdividing Surfaces


Glacial SedimentsGlacial Sediments Facies of continental glacial settings Facies of continental glacial settings

Grounded Ice FaciesGrounded Ice FaciesGlaciofluvial facies Glaciofluvial facies Glacial lacustrine faciesGlacial lacustrine facies

– Facies of proglacial lakesFacies of proglacial lakes– Facies of periglacial lakesFacies of periglacial lakes

Cold-climate periglacial faciesCold-climate periglacial facies

Facies of marine glacial settingsFacies of marine glacial settingsProximal faciesProximal faciesContinental Shelf faciesContinental Shelf faciesDeepwater faciesDeepwater facies


Glacial Systems - Conclusions Glacial Systems - Conclusions Signal extremes in local climate & sea level positionSignal extremes in local climate & sea level position Stratigraphic markers of glacial eventsStratigraphic markers of glacial events Source of Source of tillite (pebbles & larger fragments supported in tillite (pebbles & larger fragments supported in

fine-grained matrix ) deposited from glaciers. fine-grained matrix ) deposited from glaciers. Massive tillite inferred deposited below ice sheets or dropping Massive tillite inferred deposited below ice sheets or dropping from marine supported ice in submarine settingfrom marine supported ice in submarine settingBanded tillite may be deposited by ice sheetsBanded tillite may be deposited by ice sheets

Laminites common in lakes (Varve), Loess dust on landLaminites common in lakes (Varve), Loess dust on land Supraglacial & pro-glacial deposits with stratified Supraglacial & pro-glacial deposits with stratified

conglomerates & sandstoneconglomerates & sandstone U Shaped valleys & glacial striae U Shaped valleys & glacial striae Mountain glaciation could be source of much downslope Mountain glaciation could be source of much downslope

fluvial sedimentfluvial sediment


Simplified Conclusions Glacial SystemsSimplified Conclusions Glacial Systems Sediment signal a mix of:Sediment signal a mix of:

Glacial carried & dumped morainesGlacial carried & dumped morainesWater born fluvial sedimentWater born fluvial sedimentLacustrian varvesLacustrian varvesAeolian loessAeolian loess

Erosion: Erosion: U-shaped valleysU-shaped valleysEroded rock surfaceEroded rock surface– GroovedGrooved– Plucked Plucked – StriatedStriated

Base level: changes in sea level.Base level: changes in sea level.

AEOLIANAEOLIANAND AND DESERTSDESERTS


Sandy Desert – N. Africa – Sandy Desert – N. Africa – GoingGoing


Aeolian System – Desert & CoastAeolian System – Desert & Coast Distribution of Aeolian systems – Holocene & Distribution of Aeolian systems – Holocene &

AncientAncient Deserts: Transport & Depositional Sytems Deserts: Transport & Depositional Sytems

Wind & Fluvial ActionWind & Fluvial Action Deposits of Modern DesertsDeposits of Modern Deserts

DunesDunesInterdunesInterdunesSheet SandsSheet Sands

Aeolian SystemsAeolian Systems Bounding SurfacesBounding Surfaces Ancient DepositsAncient Deposits


Simplified Desert Systems signalsSimplified Desert Systems signals Sediment signal a mix of:Sediment signal a mix of:

Aeolian sediment – dunes and sheetsAeolian sediment – dunes and sheetsWater born intermittent fluvial sedimentWater born intermittent fluvial sedimentPlayas and lakesPlayas and lakesAeolian loessAeolian loess

Erosion: Erosion: Water table “Stokes Surfaces” marks limitWater table “Stokes Surfaces” marks limitIncised valleysIncised valleysGravel remnantsGravel remnantsRock pavementsRock pavementsVentifactsVentifacts

Base level: changes in ground water level.Base level: changes in ground water level.


DesertDesertRegion with low precipitationRegion with low precipitation

Usually less than 25 cm rain per yearUsually less than 25 cm rain per yearDistributionDistribution

Most related to descending airMost related to descending airBelts at 30 degrees North & South latitudeBelts at 30 degrees North & South latitudeRain shadow of mountainsRain shadow of mountainsGreat distance from oceansGreat distance from oceansTropical coasts beside cold ocean currentsTropical coasts beside cold ocean currentsPolar dessertsPolar desserts



Earth'sEarth'sGeneralGeneral

CirculationCirculation



Rain Shadow Deserts Rain Shadow Deserts


Deserts – Dune FactoriesDeserts – Dune Factories

Lack of through-flowing streamsLack of through-flowing streams Internal drainageInternal drainageLocal base levelsLocal base levelsDesert thunderstormsDesert thunderstorms

Flash floodsFlash floods– MudflowsMudflows

Common characteristics:-

Dominated by water transportation


Deserts – Depositional SystemsDeserts – Depositional Systems

Margin rimmed by incised seasonal streams Margin rimmed by incised seasonal streams (Wadiis or Arroyo)(Wadiis or Arroyo)

In turn flanked by alluvial fans and rock In turn flanked by alluvial fans and rock pavements or bajada pavements or bajada

Intermittent drainage supplying sedimentIntermittent drainage supplying sediment Dunes Dunes PlayasPlayas

Dunes fed by water transported sediment


Bajada Bajada “Pediment”“Pediment”

&&AlluvialAlluvial

Fans Fans --

NamibiaNamibia


Alluvial fans – Death Alluvial fans – Death ValleyValley


Salt Pan & Alluvial Fans – Death ValleySalt Pan & Alluvial Fans – Death Valley


Sediment Source - Deserts & CoastsSediment Source - Deserts & Coasts Abundant sediment supply (sand, silt)Abundant sediment supply (sand, silt) Favorable wind regimesFavorable wind regimes Grain transport in windGrain transport in wind Transport populations & resultant depositsTransport populations & resultant deposits

i. Traction (deflation pavements)i. Traction (deflation pavements)ii. Saltation (sand dunes)ii. Saltation (sand dunes)iii. Suspension (loess)iii. Suspension (loess)III. Subenvironments of eolian dune systemsIII. Subenvironments of eolian dune systems

Dominated by water transportation


Wind Erosion and TransportationWind Erosion and Transportation

SandSandMoves along ground- saltationMoves along ground- saltationSandstormsSandstormsSandblasting up to 1 meterSandblasting up to 1 meter

– VentifactVentifactDeflationDeflation

BlowoutBlowoutDust stormsDust storms


Sand Movement Sand Movement


Brice Canyon - UtahBrice Canyon - Utah


Arches National Park – UtahArches National Park – Utah



Dust stormsDust stormsSandSand

Moves along ground- saltationMoves along ground- saltationSandstormsSandstormsSandblasting up to 1 meterSandblasting up to 1 meter


BlowoutBlowout



Wind ActionWind ActionStrong in desert because:Strong in desert because:

Low humidityLow humidityGreat temperature rangesGreat temperature rangesMore effective because of lack of More effective because of lack of vegetationvegetation

Effective erosion in deserts because Effective erosion in deserts because sediment is drysediment is dry














RedSeaDustStorm

Red Sea Dust StormRed Sea Dust Storm


North Africa - Sea Dust StormNorth Africa - Sea Dust Storm



Dust stormsDust stormsWind-blown dust accumulates in the deep Wind-blown dust accumulates in the deep

ocean floor at a rate of 0.6 x 1014 g/year.ocean floor at a rate of 0.6 x 1014 g/year.



LoessLoess


Wind DepositionWind Deposition

LoessLoessGravel PavementsGravel Pavements

Desert varnish & “petroglyphs”Desert varnish & “petroglyphs”Sand DunesSand Dunes

Well-sorted, well-rounded sand grainsWell-sorted, well-rounded sand grainsSlip faceSlip face

– Angle of reposeAngle of repose

Wind ripplesWind ripples


Desert Pavement FormationDesert Pavement Formation

















Barchan Dunes - JordanBarchan Dunes - Jordan


Zion National Park - UtahZion National Park - Utah










Dune EvolutionDune Evolution


Hierarchies exhibited by aeolian Hierarchies exhibited by aeolian and associated sedimentsand associated sediments GrainsGrains RipplesRipples Dunes Dunes Interdune unconfined sheetsInterdune unconfined sheets Confined bodies of wadii channel fillsConfined bodies of wadii channel fills Playa unconfined sheets of heterogenous Playa unconfined sheets of heterogenous

chemical, wind and water transported chemical, wind and water transported clastic sedimentsclastic sediments


Mechanisms of Aeolian Mechanisms of Aeolian TransportationTransportation Rolling: 2-4 mmRolling: 2-4 mm Surface creepSurface creep 20-25% of sand moves by grains shifted by 20-25% of sand moves by grains shifted by

impacting saltating grains < 2 mmimpacting saltating grains < 2 mm Suspension: fine sand, silt, claySuspension: fine sand, silt, clay Grains 0.1 mm are most easily moved by Grains 0.1 mm are most easily moved by

wind; mostly > 2 m above the ground wind; mostly > 2 m above the ground surfacesurface


Mice Tracks & Mice Tracks & RipplesRipples

White Sands, NMWhite Sands, NM


Ripples on DuneRipples on Dune



Types of dunesTypes of dunesBarchanBarchanTransverse duneTransverse duneParabolic duneParabolic duneLongitudinal duneLongitudinal dune


Salt Pan – West Texas, El CapitanSalt Pan – West Texas, El Capitan

BARCHAN LONGITUDINAL

TRANSVERSE PARABOLIC

BARCHINOID STAR


North Africa - Sea Dust StormNorth Africa - Sea Dust StormStar Dunes – NamibiaStar Dunes – Namibia


Sahara – Barchans & CamelsSahara – Barchans & Camels


Navajo SandstoneNavajo Sandstone


Cross-bedded Navaho SandstoneCross-bedded Navaho Sandstone


NavajoNavajoSandstoneSandstone


Quaternary of UAE – Stokes SurfaceQuaternary of UAE – Stokes Surface



Base level change punctuates the sandstone with erosion surfaces!



Base level change punctuates the Base level change punctuates the sandstone with erosion surfaces!sandstone with erosion surfaces!



Base level change punctuates the Base level change punctuates the sandstone with erosion surfaces!sandstone with erosion surfaces!


Some characteristics of desertsSome characteristics of deserts

Stream channels normally dryStream channels normally drycovered with sand & gravelcovered with sand & gravelNarrow canyons with vertical wallsNarrow canyons with vertical walls

Resistance of rocks to weatheringResistance of rocks to weatheringDesert topography typically steep and angularDesert topography typically steep and angular


Aeolian Aeolian Sediment -Sediment - Critical Character Critical Character Aeolian sediments evidenced by x-bedding with Aeolian sediments evidenced by x-bedding with

high angle (30-34 degrees) high angle (30-34 degrees) Horizontal thin laminae common locallyHorizontal thin laminae common locally Sand rounded and frostedSand rounded and frosted Quartz coated by iron oxide suggests hot arid Quartz coated by iron oxide suggests hot arid

and/or seasonally humid climate (exceptions)and/or seasonally humid climate (exceptions) Well Sorted: often unimodal but if bimodal two Well Sorted: often unimodal but if bimodal two

populations presentpopulations present Silt and clay minimalSilt and clay minimal


Small & large scale cross bedding, with multiple Small & large scale cross bedding, with multiple orientations within horizontal beddingorientations within horizontal bedding

Grains in laminae well sorted, especially finer Grains in laminae well sorted, especially finer sizes, sharp differences in size between laminasizes, sharp differences in size between lamina

Size ranges from silt (60 mu) to coarse & (2mm)Size ranges from silt (60 mu) to coarse & (2mm) Max size transported by wind 1 cm but rare grains Max size transported by wind 1 cm but rare grains

over 5 mmover 5 mm Larger grains (0.5 - 1.mm) often well rounded Larger grains (0.5 - 1.mm) often well rounded Sands free of clay and clay drapes rareSands free of clay and clay drapes rare Uncemented sands have frosted surfacesUncemented sands have frosted surfaces Mica usually absentMica usually absent

Aeolian Aeolian Sediment -Sediment - Critical Character Critical Character

Rules of thumb - Glennie1970


Aeolian sediment interpretationAeolian sediment interpretation Analyse sedimentology & internal architecture Analyse sedimentology & internal architecture

with outcrop, cores and downhole imaging with outcrop, cores and downhole imaging Identify & seperate single aggradational units Identify & seperate single aggradational units

bounded by regional deflation surfaces (deep-bounded by regional deflation surfaces (deep-scoured to flat surfaces) scoured to flat surfaces)

Genetic models from cyclic recurrence in facies Genetic models from cyclic recurrence in facies Aggradation characterises near- continuous Aggradation characterises near- continuous

accumulationaccumulation Internal facies evolution related to differences in Internal facies evolution related to differences in

sediment budget & moving water table sediment budget & moving water table Palaeosols provide evidence of climate change Palaeosols provide evidence of climate change


Conclusions - Desert Systems - Simplified Conclusions - Desert Systems - Simplified Sediment signal a mix of:Sediment signal a mix of:

Aeolian sediment – dunes and sheetsAeolian sediment – dunes and sheetsWater born intermittent fluvial sedimentWater born intermittent fluvial sedimentPlayas and lakesPlayas and lakesAeolian loessAeolian loess

Erosion: Erosion: Water table “Stokes Surfaces” marks limitWater table “Stokes Surfaces” marks limitIncised valleysIncised valleysGravel remnantsGravel remnantsRock pavementsRock pavementsVentifactsVentifacts

Base level: changes in ground water level.Base level: changes in ground water level.

LAKE LAKE AND AND ORGANICSORGANICS

Lakes Lakes Are Are

EphemeralEphemeral


Lacustrian SystemsLacustrian Systems Critical characteristics of system?Critical characteristics of system? Geomorphologic & tectonic setting Geomorphologic & tectonic setting Dominant sedimentary processesDominant sedimentary processes FaciesFacies

Subdividing surfacesSubdividing surfacesLithologyLithologySedimentary structuresSedimentary structuresGeometries – Confined versus open Geometries – Confined versus open Fauna & floraFauna & flora


Lake Systems – Simplified Signals Lake Systems – Simplified Signals Sediment signal a mix of:Sediment signal a mix of:

Lake Center –sheets and incised & unconfined turbidite cyclesLake Center –sheets and incised & unconfined turbidite cyclesMargins marked by alluvial fans & fluvial sedimentMargins marked by alluvial fans & fluvial sedimentReducing setting that favors organic preservationReducing setting that favors organic preservationSignal cycles in order from:Signal cycles in order from:

– CClastics & organicslastics & organics– Limestone & organicsLimestone & organics– Evaporites & organics Evaporites & organics

Base level: changes in ground water levelBase level: changes in ground water level Origin of large lakes:Origin of large lakes:

Continental break upContinental break upContinental collision Continental collision Sags on cratonSags on craton


Significance of Lake Systems Significance of Lake Systems Signal extremes in local climate & geochemistrySignal extremes in local climate & geochemistry Stratigraphic markers (Organics trap radioactive minerals)Stratigraphic markers (Organics trap radioactive minerals) Major source of hydrocarbons along Atlantic MarginsMajor source of hydrocarbons along Atlantic Margins Major source of oil shale & gas in western USA & CanadaMajor source of oil shale & gas in western USA & Canada Major source ofMajor source of

Trona (Hydrated Sodium Bicarbonate Carbonate)Trona (Hydrated Sodium Bicarbonate Carbonate)Borax (Hydrated Sodium Borate)Borax (Hydrated Sodium Borate)Sulfohalite (NaSulfohalite (Na66ClF(SOClF(SO44))22))

Hanksite (Sodium Potassium Sulfate Carbonate Chloride)Hanksite (Sodium Potassium Sulfate Carbonate Chloride)


Lake Geomorphologic & Tectonic Setting Lake Geomorphologic & Tectonic Setting

Major rifted, & faulted (Break-up) continental terrains – Major rifted, & faulted (Break-up) continental terrains – E. AfricaE. Africa Major final fill of foreland basin – Major final fill of foreland basin – Caspian & AralCaspian & Aral Continental sags – Continental sags – Victoria, Kenya, Uganda, and EyreVictoria, Kenya, Uganda, and Eyre Glacial features including:Glacial features including:

Moraine damming and/or ice scouring – Moraine damming and/or ice scouring – Great LakesGreat Lakes Ice dammingIce damming

Landslides or mass movementsLandslides or mass movements Volcanic activity including: Volcanic activity including:

Lava dammingLava dammingCrater explosion and collapse – Crater explosion and collapse – Crater LakeCrater Lake

Deflation by wind scour or damming by wind blown sand - Deflation by wind scour or damming by wind blown sand - FayumFayum Fluvial activity includingFluvial activity including

Oxbow lakes Oxbow lakes Levee lakes, Levee lakes, Delta & barrier island entrapmentDelta & barrier island entrapment

Temporary features forming 1% of earths’s land surface, filling:-Temporary features forming 1% of earths’s land surface, filling:-


Initial Initial BreakupBreakupA Salt A Salt Filled Filled BasinBasinMay be May be CreatedCreated

Mix of Mix of high high salinity to salinity to fresh fresh water, water, organic organic rich to rich to evaporitievaporiticc


Lake TanganyikaLake Tanganyika




Lake levels have varied historical and earlierLake levels have varied historical and earlier Fossil and living stromatolites abundant around Fossil and living stromatolites abundant around

the margins of Lake Tanganyika, Africa provides a the margins of Lake Tanganyika, Africa provides a source of paleolimnologic and paleoclimatic source of paleolimnologic and paleoclimatic information for the late Holoceneinformation for the late Holocene

late Holocene carbonates suggests that the late Holocene carbonates suggests that the surface elevation of the lake has remained near surface elevation of the lake has remained near the outlet level, with only occasional periods of the outlet level, with only occasional periods of closureclosure

In past the lake draw down encouraged In past the lake draw down encouraged evaporites evaporites





Lakes formed Lakes formed between between splitting splitting

continentscontinents


Restricted Restricted Entrances Entrances

To SeaTo Sea

Isolated linear

Isolated linear

Belt of interior

Belt of interiordrainage

drainage Regional Regional Drainage Drainage

Away Away From MarginFrom Margin

Arid Tropics Air System Arid Tropics Air System

Wide Envelope of surrounding continentsWide Envelope of surrounding continents

Organic Rich Lake FillOrganic Rich Lake Fill



Lakes flanking Major Mountain ChainsLakes flanking Major Mountain Chains


Bodies of fresh to saline water trapped on Bodies of fresh to saline water trapped on craton behind major mountain chainscraton behind major mountain chains

Tend to act as traps to clastics, carbonates Tend to act as traps to clastics, carbonates and evaporitic sedimentsand evaporitic sediments

Climatic change is recorded in the record Climatic change is recorded in the record of the sediment fillof the sediment fill

Water draw down encourages evaporites Water draw down encourages evaporites

Caspian and the Arral SeaCaspian and the Arral Sea


CaspianCaspian


Aral SeaAral Sea


Great LakesGreat Lakes


Bodies of fresh water trapped on glacially Bodies of fresh water trapped on glacially scoured depressions on craton behind scoured depressions on craton behind glacial moraines glacial moraines

Act as traps to clastic sedimentsAct as traps to clastic sediments Climatic change is recorded in record of Climatic change is recorded in record of

sediment fillsediment fill Water draw down encourages precipitates Water draw down encourages precipitates

Great Lakes Great Lakes


Lake Constance - Lake Constance - SwitzerlandSwitzerland



Ice Dammed Lake – AlaskaIce Dammed Lake – Alaska


Lake Response to StratificationLake Response to Stratification


Lake Sedimentary faciesLake Sedimentary facies Sedimentary signal like that of a foreshortened Sedimentary signal like that of a foreshortened

Marine settingMarine setting Narrow shores with beaches and deltasNarrow shores with beaches and deltas Finer sediments and turbidites fill the lake center Finer sediments and turbidites fill the lake center


Lake Sedimentary faciesLake Sedimentary facies Presence of freshwater fossilsPresence of freshwater fossils Lake sediments commonly better sorted than fluvial and periglacial Lake sediments commonly better sorted than fluvial and periglacial

sedimentssediments May (or may not) display a tendency toward fining upward and May (or may not) display a tendency toward fining upward and

inward towards the basin centerinward towards the basin center Lake sediments are predominantly fine grained sediments either Lake sediments are predominantly fine grained sediments either

siliciclastic muds but may be carbonate sediments and evaporates siliciclastic muds but may be carbonate sediments and evaporates Typical sequence may produced as the lake dries up with a Typical sequence may produced as the lake dries up with a

coarsening upward sequence from laminated shales, marls and coarsening upward sequence from laminated shales, marls and limestones to rippled and cross-bedded sandstone and possibly limestones to rippled and cross-bedded sandstone and possibly conglomeratesconglomerates

Lake sediment fill often shows cyclic alternation of laminaeLake sediment fill often shows cyclic alternation of laminae Varves produced by seasonal variations in sediment supply and Varves produced by seasonal variations in sediment supply and

lake circulation which changes the chemistry of the lakeslake circulation which changes the chemistry of the lakes


Lacustrian sedimentary geometriesLacustrian sedimentary geometries Shore marked by linear beachesShore marked by linear beaches Coarse to fine slopeCoarse to fine slope Deeper water lake laminae and turbiditesDeeper water lake laminae and turbidites Eclectic clastic and evaporitic sedmentsEclectic clastic and evaporitic sedments


GreenGreenRiver River LakeLake


Green River Lake FillGreen River Lake Fill


Green Green RiverRiver

– – Systems Systems

&&FaciesFacies


Green River SectionGreen River Section




Green River Green River SectionSection


Green River Green River Fauna & FloraFauna & Flora


East African Lake MarginEast African Lake Margin





Conclusions - Lake Systems Conclusions - Lake Systems Sediment signal a mix of:Sediment signal a mix of:

Lake Center –sheets and incised & unconfined turbidite cyclesLake Center –sheets and incised & unconfined turbidite cyclesMargins marked by alluvial fans & fluvial sedimentMargins marked by alluvial fans & fluvial sedimentReducing setting that favors organic preservationReducing setting that favors organic preservationSignal cycles in order from:Signal cycles in order from:

– CClastics & organicslastics & organics– Limestone & organicsLimestone & organics– Evaporites & organics Evaporites & organics

Base level: changes in ground water levelBase level: changes in ground water level Origin of large lakes:Origin of large lakes:

Continental break upContinental break upContinental collision Continental collision Sags on cratonSags on craton

Lakes Lakes Are Are

EphemeralEphemeral

End of the LectureEnd of the Lecture

Lets go for lunch!!!Lets go for lunch!!!

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Clastic depositional system

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