Sediment Routing Systems: The Fate of Sediment from Source to Sink

422 Pages·2017·35.545 MB·English

by  Philip Allen

SEDIMENT ROUTING SYSTEMS
This cutting-edge summary combines ideas from several sub-disciplines, including
geology, geomorphology, oceanography and geochemistry, to provide an integrated view
of Earth surface dynamics in terms of sediment generation, transport and deposition.
Introducing a global view of fundamental concepts underpinning source-to-sink studies,
it provides an analysis of the component segments which make up sediment routing
systems. The functioning of sediment routing systems is illustrated through calculations
ofdenudationandsedimentationaswellastheresponsetoexternaldrivers;withthefinal
sections focusing on the stratigraphic record of sediment routing systems. Containing
quantitativesolutionstoawiderangeofproblemsinEarthsurfacedynamics,thisbookis
suitableforgraduatestudentsaswellasacademicandprofessionalresearchers.
philip a. allen is Emeritus Professor of Sedimentary Geology at Imperial College
Londonandaprocess-orientedEarthscientistwithaparticularinterestintheinteractions
andfeedbacksbetweenthesolidEarthandits‘exosphere’throughthecriticalinterfaceof
theEarth’ssurface.HehasreceivedtheRoyalSocietyWolfsonResearchMeritAwardfor
2006 to 2011 and the Lyell Medal from the Geological Society of London in 2007. He
servedontheCounciloftheGeologicalSocietyfrom2008to2012,andwasSecretaryof
theScienceCommitteefrom2009to2012.
In this new book, Philip Allen has distilled a lifetime of insightful study of the Earth’s
surface into a wide ranging and rigorous synthesis of planetary sediment processes.
SedimentRoutingSystemsisthefirsttousetheideaofglobalsedimentrouting–‘following
the sediment’ – to provide a framework for synthesis across environments and scales, to
integrate the source and sink sides of the routing system, and to link geochemical and
particulate fluxes. It manages to do this in a quantitative framework that is carefully
formulated, accessible, and perfectly pitched in clarity and detail. Sediment Routing
Systemsisalandmarkandmasterpiece;formanyEarthscientists,itwillbealltheyneed
intermsofglobalsedimentdynamics.
ChrisPaola
UniversityofMinnesota
Ifreadingthesedimentaryrecordisthedestination,thenthisbookisabrilliantcompanion
fortheroad,rangingwidelyfrombedloadtoorganiccarbonandprovidingthoroughdetail
on processes and methods at every turn. Philip Allen turns the sediment routing system
fromPandora’sboxintoadynamicsource-to-sinkcascade.
NielsHovius
GFZGermanResearchCentreforGeosciences
Sediment Routing Systems is the first complete, quantitative process-based account of
sediment generation, transport and deposition in book format. In true style, ahead of
anyoneelse,PhilipAllengivesanextremelythorough,comprehensiveviewofallprocess
aspects of source-to-sink systems. This book combines theoretical with practical aspects
and will be an obvious choice as an advanced text book in universities and as a key
referencebookforprofessionalgeologistsdealingwithenergyandEarthsystems.
OleJ.Martinsen
ChiefGeologistandVicePresident,Statoil
SEDIMENT ROUTING SYSTEMS
The Fate of Sediment from Source to Sink
PHILIP A. ALLEN
ImperialCollegeLondon
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www.cambridge.org
Informationonthistitle:www.cambridge.org/9781107091993
DOI:10.1017/9781316135754
©PhilipA.Allen2017
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andtotheprovisionsofrelevantcollectivelicensingagreements,
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permissionofCambridgeUniversityPress.
Firstpublished2017
PrintedintheUnitedKingdombyTJInternationalLtd.PadstowCornwall
AcataloguerecordforthispublicationisavailablefromtheBritishLibrary.
LibraryofCongressCataloging-in-PublicationData
Names:Allen,PhilipA.,author.
Title:Sedimentroutingsystems:thefateofsedimentfromsourcetosink/
PhilipA.Allen,ImperialCollege,London.
Description:Cambridge,UnitedKingdom;NewYork,NY:CambridgeUniversity
Press,2017.|Includesbibliographicalreferencesandindex.
Identifiers:LCCN2017014847|ISBN9781107091993(Hardback:alk.paper)
Subjects:LCSH:Sediments(Geology)
Classification:LCCQE471.2.A432017|DDC551.3/54–dc23LCrecord
availableathttps://lccn.loc.gov/2017014847
ISBN978-1-107-09199-3Hardback
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Contents
Preface pageix
PartI AGlobalViewofSedimentRoutingSystems 1
1 SedimentRoutingSystems:FirstConcepts 3
1.1 HowSedimentRoutingSystemsFunction 3
1.2 TheSedimentCascade 11
2 TheGlobalCharacterofRiverBasins 20
2.1 MappingoftheTerrestrialSegmentofSedimentRoutingSystems 20
2.2 TopologyofRiverBasins 27
2.3 GlobalParticulateSedimentandSoluteDeliverytotheOcean 30
2.3.1 Run-off 32
2.3.2 ParticulateLoads 35
2.3.3 DissolvedSolids 44
2.4 ChemicalWeatheringFluxesAssociatedwithGlaciation 49
3 GlobalBiogeochemicalCycles 54
3.1 BiogeochemistryofWorldRivers 54
3.1.1 GlobalWaterChemistry 56
3.1.2 ChemistryoftheParticulateLoad 60
3.1.3 TheEstuarineFilter 61
3.2 TheFateofOrganicCarbon 62
3.2.1 ParticulateOrganicCarbon 63
3.2.2 DissolvedOrganicCarbon 65
3.2.3 BurialofOrganicCarbonandGlobalClimate 66
3.2.4 OrganicCarbonintheAmazonSedimentRouting
System 69
3.2.5 OrganicCarbonthroughGlacial-InterglacialCycles 71
3.2.6 ParticulateOrganicCarbonatActiveandPassive
Margins 74
3.3 NutrientFluxes 78
v
vi Contents
PartII TheSegmentsofSedimentRoutingSystems 81
4 TheCatchment-FluvialSegment 83
4.1 HillslopesandBedrockChannels 86
4.1.1 OutletSpacingofTransverseDrainageBasins 86
4.1.2 BedrockChannels 87
4.1.3 EffectofTectonicUpliftonRiverLongProfiles 92
4.1.4 Hillslopes 93
4.2 Basin-MarginFans 100
4.3 AxialversusTransverseDrainage 104
4.4 AlluvialRivers 108
4.4.1 FluvialGeomorphicElementsinSedimentaryBasins 108
4.4.2 Long-RangeSedimentTransportandDeposition 110
4.4.3 RiverPlanformPatternsandLongProfilesofAlluvialRivers 114
4.5 FloodplainsasSedimentStores 116
4.6 PalaeohydrologyofRivers 128
5 TheContinentalShelfSegment 131
5.1 DynamicsatRiverMouths 131
5.2 NaturalRangeofDeltaicandSubaqueousClinoforms 140
5.3 SimpleModelsofDeltaProgradation 141
5.4 SedimentTransportontheShelf 151
5.5 RiverPlumesandDispersalScaling 155
5.6 TheBottomBoundaryLayer 160
5.7 InteractionbetweenOceanCurrentsandCoastalWaters 166
6 TheDeepMarineSegment 170
6.1 SlopeMorphology 170
6.2 SedimentTransfertotheDeepSea:CriticalRoleofSubmarineCanyons 174
6.3 BasinPlainsandDeepSeaFans 176
6.4 Deep-WaterCirculation 184
6.5 RecordofGlaciationintheDeepSea 185
PartIII TheFunctioningofSedimentRoutingSystems 191
7 DenudationandSedimentation 193
7.1 RangeofTechniques 193
7.2 ControlsonSedimentYieldandErosionRate 196
7.2.1 ErosionRateinGlaciatedBasins 198
7.3 TheBQARTPredictor 202
7.4 EstimatesofErosionfromStrontiumIsotopeRatios 206
7.5 DenudationfromLow-TemperatureThermochronometry 211
7.5.1 FissionTrackAnalysis 211
7.5.2 HeliumDiffusion:(U-Th)/He 216
Contents vii
7.6 DenudationfromAnalysisofCosmogenicNuclides 218
7.6.1 Catchment-AveragedErosionRatefromCosmogenicNuclide
Analysis 222
7.7 Sedimentation:Patterns,RatesandHierarchies 226
7.7.1 Life-SpanofSedimentaryBasins 226
7.7.2 SedimentationRatesandHierarchies 227
7.7.3 StratigraphicCompleteness 231
7.7.4 BedThicknessStatistics 236
8 DynamicsofSedimentRoutingSystems 240
8.1 MovingBoundaries 240
8.1.1 TheGravelFrontandGravelCline 240
8.1.2 TheShoreline 244
8.2 MassBalance 247
8.3 StochasticTheoryofParticleTrajectories 250
8.4 TowardsaVocabularyforTectonicLandscapes 256
8.5 TransientResponseswithinSedimentRoutingSystems 259
8.5.1 AlluvialRivers 261
8.5.2 HillslopeErosion 262
8.5.3 Catchment-FanSystems 263
8.5.4 GrowthofExtensionalFaultArrays 269
8.5.5 LateralGrowthofaFaultTip 273
8.5.6 KnickpointMigration 274
8.5.7 UnroofingofTectonicFolds 277
8.6 CouplingofTectonicsandSurfaceProcesses 279
8.6.1 OrogenicWedgesandForelandBasinSystems 280
8.6.2 CoupledTectonic-ErosionModelsofForelandBasinSystems 285
8.6.3 ArraysofContractionalFolds 288
8.7 TransformationofSignalsinSedimentRoutingSystems 291
PartIV TheStratigraphicRecordofSedimentRoutingSystems 295
9 SedimentProduction,EvolutionandProvenance 297
9.1 TheFormationofSediment 297
9.2 Precipitation,VegetationandErosion 304
9.3 Grain-SizeMixofSedimentSuppliedtoBasins 309
9.3.1 SimulationsUsingaVariableGrain-SizeMixintheSupply 313
9.4 Grain-SizeFractionationinSedimentRoutingSystems 318
9.4.1 DownstreamChangesinHydraulicGeometry 318
9.4.2 FractionationofGrainSizeDuringDispersal 319
9.4.3 Down-SystemFiningofGravelbySelectiveDeposition 323
9.4.4 EffectsofClimateChangeonGrain-SizeTrends 326
9.5 LinkingSourcetoSink:ProvenanceTools 330
viii Contents
10 SedimentRoutingSystemsandSequenceStratigraphy 335
10.1 InsightsfromQuaternaryStudies 335
10.2 OrbitallyDrivenSignalsinStratigraphy 343
10.2.1 EffectsofSeaLevelChange 346
10.3 AnalogueandNumericalExperimentsofSequenceArchitectures 349
10.3.1 AutostratigraphyResultingfromInternalDynamics 351
10.4 CyclesandtheGlobalSeaLevelChart 356
10.4.1 AnOrderedHierarchy? 356
References 364
Index 403
Preface
By far the most powerful way to find out about Earth’s history is to study the sediments
and sedimentary rocks comprising the stratigraphic record. With this in mind, Doyle and
Bennett(1998)statedconfidentlythat
StratigraphyisthekeytounderstandtheEarth,itsmaterials,structureandpastlife.Itencompasses
everythingthathashappenedinthehistoryoftheplanet.
ChrisPaola(www.esci.umn.edu/people/chris-paola)observedlyricallyandcautiously
RachelCarsonwrotethat‘ThesedimentsareasortofepicpoemoftheEarth’.Unfortunatelythis
poemiswritteninalanguagewedon’tunderstand.
Part of this lack of understanding of the language of the epic poem of the Earth has its
originsintheimperfectrecordingofeventsinthestratigraphicrecord,andparticularlyin
thedifficultyofdecipheringwhattheEnglishpoetTennyson(1809–1892)calledthe‘long
result of Time’, since the familiar processes responsible for the liberation, transport and
depositionofsedimentarebestknownattheveryshorttimescalesofhumanobservation.
AsJamesHuttonwrote(1785),
itisnotinhumanrecord,butinnaturalhistory,thatwearetolookforthemeansofascertainingwhat
hasalreadybeen.
The other part of our lack of understanding derives from the difficulty of seeing the big
picturewithallofitsfeedbacksandlinkages,whichallowsustoeffectively‘jointhedots’
(Allen,2014)(ch.1).Thisbig,integratedpictureisthatofthesedimentroutingsystem.
Sedimentroutingsystemsarethedynamicalsystemsthatlinkthefateofsedimentfrom
sourcetosinkandintegratetheprocessestakingplaceatornearthesurfaceoftheEarth,
and the resultant depositional products, at the timescales relevant to the understanding of
stratigraphy.Theyinvolvea‘cascade’ofsedimentfromprimarilyerosionalsourceareasto
depositionalsinks,andthereforeareresponsibleforuplandlandscapesandtheirsediment
andsoluteeffluxes,transportacrossthecontinentalsurfaceanddeliverytotheocean,and
dispersalintolong-termdepositionalsitesinthedeepsea.Theprocessesactinginsediment
routingsystemsthereforeshapeerosionalanddepositionallandscapesandextractsediment
tobuildstratigraphy,theprimaryarchiveofthe‘epicpoemoftheEarth’.
ix