CHAPTER 5: MarineCHAPTER 5: Marine
SedimentsSediments
Marine sedimentsMarine sediments
 Eroded rock particles and fragmentsEroded rock particles and fragments
 Transported to...
Classification of marineClassification of marine
sedimentssediments
 Classified by originClassified by origin
 Lithogeno...
Lithogenous sedimentsLithogenous sediments
 Eroded rock fragments from land (Eroded rock fragments from land (originorigi...
BY PERCENTTransport Mechanism
S
Lithogenous sedimentsLithogenous sediments
Fig. 4.5
S
Lithogenous sedimentsLithogenous sediments
 Most lithogenous sediments at continentalMost lithogenous sediments at contin...
Smaller particles have a larger SA/Vol. ratio,
increasing the frictional drag (sinking rates) and
making small particles s...
Brazos River Meets the GulfBrazos River Meets the Gulf
of Mexicoof Mexico
FLOCCULATIONFLOCCULATION - THE JOINING- THE JOIN...
Brazos River
Distribution of sedimentsDistribution of sediments
 NeriticNeritic
 Shallow water depositsShallow water deposits
 Close...
Neritic lithogenous sedimentsNeritic lithogenous sediments
 Beach depositsBeach deposits
 Mainly wave-deposited quartz-r...
Pelagic lithogenous sedimentsPelagic lithogenous sediments
 Sources of fine material:Sources of fine material:
 Volcanic...
BiogenousBiogenous marine sedimentsmarine sediments
 Hard remains of once-livingHard remains of once-living
organismsorga...
Biogenous marine sedimentsBiogenous marine sediments
 Commonly eitherCommonly either calcium carbonatecalcium carbonate
(...
SilicaSilica in biogenic sedimentsin biogenic sediments
 DiatomsDiatoms (algae)(algae)
 PhotosyntheticPhotosynthetic
Siliceous oozeSiliceous ooze
 Seawater undersaturated with silicaSeawater undersaturated with silica
 Siliceous ooze com...
Calcium carbonateCalcium carbonate in biogenousin biogenous
sedimentssediments
 CoccolithophCoccolithoph
oresores (algae)...
S
White Cliffs of Dover
Calcium carbonateCalcium carbonate in biogenousin biogenous
sedimentssediments
 ForaminiferaForaminifera
(protozoans)(pro...
Living Foraminifera
Distribution of biogenousDistribution of biogenous
sedimentssediments
 Factors controlling distributionFactors controllin...
Calcareous ooze and the CCDCalcareous ooze and the CCD
 Warm, shallow ocean saturated withWarm, shallow ocean saturated w...
Distribution of calcareous oozes inDistribution of calcareous oozes in
surface sediments of modern seafloorsurface sedimen...
Hydrogenous marine sedimentsHydrogenous marine sediments
 Minerals precipitate directly fromMinerals precipitate directly...
Iron-Manganese nodulesIron-Manganese nodules
 Fist-sized lumps of manganese, iron, andFist-sized lumps of manganese, iron...
ManganeseManganese
nodulesnodules
Fig. 4.26
Cosmogenous marineCosmogenous marine
sedimentssediments
 Macroscopic meteor debrisMacroscopic meteor debris
 Microscopic...
Microtektites - extraterrestrial
Mixtures of marine sedimentsMixtures of marine sediments
 Usually mixture of different sedimentUsually mixture of differe...
Distribution of neritic and pelagic marineDistribution of neritic and pelagic marine
sedimentssediments
Fig. 4.19
WHS Ocean -Marine Sed.
WHS Ocean -Marine Sed.
WHS Ocean -Marine Sed.
WHS Ocean -Marine Sed.
WHS Ocean -Marine Sed.
WHS Ocean -Marine Sed.
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WHS Ocean -Marine Sed.

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WHS Ocean -Marine Sed.

  1. 1. CHAPTER 5: MarineCHAPTER 5: Marine SedimentsSediments
  2. 2. Marine sedimentsMarine sediments  Eroded rock particles and fragmentsEroded rock particles and fragments  Transported to or produced in the oceanTransported to or produced in the ocean  Deposit by settling through water columnDeposit by settling through water column  Oceanographers decipher Earth historyOceanographers decipher Earth history through studying sedimentsthrough studying sediments S
  3. 3. Classification of marineClassification of marine sedimentssediments  Classified by originClassified by origin  LithogenousLithogenous (derived from(derived from landland))  BiogenousBiogenous (derived from(derived from organismsorganisms))  HydrogenousHydrogenous also called authigenicalso called authigenic (derived from(derived from waterwater))  CosmogenousCosmogenous (derived from(derived from outerouter spacespace))
  4. 4. Lithogenous sedimentsLithogenous sediments  Eroded rock fragments from land (Eroded rock fragments from land (originorigin))  TransportedTransported from landfrom land byby  Water (e.g.,Water (e.g., riverriver transported sediment)transported sediment)  WindWind (e.g., windblown dust)(e.g., windblown dust)  IceIce (e.g., ice-rafted rocks)(e.g., ice-rafted rocks)  Gravity (e.g.,Gravity (e.g., turbidity currentsturbidity currents))
  5. 5. BY PERCENTTransport Mechanism
  6. 6. S
  7. 7. Lithogenous sedimentsLithogenous sediments Fig. 4.5 S
  8. 8. Lithogenous sedimentsLithogenous sediments  Most lithogenous sediments at continentalMost lithogenous sediments at continental marginsmargins  Coarser sediments closer to shoreCoarser sediments closer to shore  Finer sediments farther from shoreFiner sediments farther from shore WHY?WHY?  Mainly mineral quartz (SiOMainly mineral quartz (SiO22))
  9. 9. Smaller particles have a larger SA/Vol. ratio, increasing the frictional drag (sinking rates) and making small particles sink more slowly than large particles
  10. 10. Brazos River Meets the GulfBrazos River Meets the Gulf of Mexicoof Mexico FLOCCULATIONFLOCCULATION - THE JOINING- THE JOINING TOGETHER OF ELECTRICALLYTOGETHER OF ELECTRICALLY CHARGED CLAY PARTICLESCHARGED CLAY PARTICLES WHICH SETTLE MORE RAPIDLYWHICH SETTLE MORE RAPIDLY THAN INDIVIDUAL ONESTHAN INDIVIDUAL ONES
  11. 11. Brazos River
  12. 12. Distribution of sedimentsDistribution of sediments  NeriticNeritic  Shallow water depositsShallow water deposits  Close to landClose to land  Dominantly lithogenousDominantly lithogenous  Typically deposited quicklyTypically deposited quickly  PelagicPelagic  Deeper water depositsDeeper water deposits  Finer-grained sedimentsFiner-grained sediments  Deposited slowlyDeposited slowly UNDERSTANDING THE PROCESSES WOULDUNDERSTANDING THE PROCESSES WOULD ALLOW YOU TO GENERATE THIS TABLEALLOW YOU TO GENERATE THIS TABLE YOURSELVESYOURSELVES
  13. 13. Neritic lithogenous sedimentsNeritic lithogenous sediments  Beach depositsBeach deposits  Mainly wave-deposited quartz-richMainly wave-deposited quartz-rich sandssands  Continental shelf depositsContinental shelf deposits  Relict sedimentsRelict sediments  Turbidite depositsTurbidite deposits  Glacial depositsGlacial deposits  High latitude continental shelfHigh latitude continental shelf
  14. 14. Pelagic lithogenous sedimentsPelagic lithogenous sediments  Sources of fine material:Sources of fine material:  Volcanic ashVolcanic ash (volcanic eruptions)(volcanic eruptions)  Wind-blown dustWind-blown dust  Fine grained material transported byFine grained material transported by deep ocean currentsdeep ocean currents  Abyssal clay (red clay)Abyssal clay (red clay)  Oxidized ironOxidized iron  Abundant if other sediments absentAbundant if other sediments absent
  15. 15. BiogenousBiogenous marine sedimentsmarine sediments  Hard remains of once-livingHard remains of once-living organismsorganisms  Shells, bones, teethShells, bones, teeth  Macroscopic (large remains)Macroscopic (large remains)  Microscopic (small remains)Microscopic (small remains)  Tiny shells or testsTiny shells or tests settle throughsettle through water columnwater column  Biogenic ooze (30% or more tests)Biogenic ooze (30% or more tests)  Mainly algae and protozoansMainly algae and protozoans
  16. 16. Biogenous marine sedimentsBiogenous marine sediments  Commonly eitherCommonly either calcium carbonatecalcium carbonate (CaCO(CaCO33)) oror silicasilica (SiO(SiO22 or SiOor SiO22.nH.nH22O)O)  UsuallyUsually planktonicplanktonic (free-floating)(free-floating)
  17. 17. SilicaSilica in biogenic sedimentsin biogenic sediments  DiatomsDiatoms (algae)(algae)  PhotosyntheticPhotosynthetic
  18. 18. Siliceous oozeSiliceous ooze  Seawater undersaturated with silicaSeawater undersaturated with silica  Siliceous ooze commonly associated withSiliceous ooze commonly associated with high biologic productivity in surface oceanhigh biologic productivity in surface ocean Fig. 4.12
  19. 19. Calcium carbonateCalcium carbonate in biogenousin biogenous sedimentssediments  CoccolithophCoccolithoph oresores (algae)(algae)  Photo-Photo- syntheticsynthetic  CoccolithsCoccoliths (nanno-(nanno- plankton)plankton)
  20. 20. S White Cliffs of Dover
  21. 21. Calcium carbonateCalcium carbonate in biogenousin biogenous sedimentssediments  ForaminiferaForaminifera (protozoans)(protozoans)  UseUse externalexternal foodfood  CalcareousCalcareous oozeooze P
  22. 22. Living Foraminifera
  23. 23. Distribution of biogenousDistribution of biogenous sedimentssediments  Factors controlling distributionFactors controlling distribution  ProductivityProductivity  Destruction (dissolution)Destruction (dissolution)
  24. 24. Calcareous ooze and the CCDCalcareous ooze and the CCD  Warm, shallow ocean saturated withWarm, shallow ocean saturated with calcium carbonatecalcium carbonate  Cool, deep ocean undersaturatedCool, deep ocean undersaturated with calcium carbonatewith calcium carbonate  LysoclineLysocline--depth at which CaCO--depth at which CaCO33 beginsbegins to dissolve rapidlyto dissolve rapidly  Calcite compensation depthCalcite compensation depth CCD--CCD-- depth where CaCOdepth where CaCO33 readily dissolvesreadily dissolves
  25. 25. Distribution of calcareous oozes inDistribution of calcareous oozes in surface sediments of modern seafloorsurface sediments of modern seafloor Why in these places?
  26. 26. Hydrogenous marine sedimentsHydrogenous marine sediments  Minerals precipitate directly fromMinerals precipitate directly from seawaterseawater  Manganese nodulesManganese nodules  PhosphatesPhosphates  CarbonatesCarbonates  Metal sulfidesMetal sulfides  Small proportion of marine sedimentsSmall proportion of marine sediments  Distributed in diverse environmentsDistributed in diverse environments
  27. 27. Iron-Manganese nodulesIron-Manganese nodules  Fist-sized lumps of manganese, iron, andFist-sized lumps of manganese, iron, and other metalsother metals  Very slow accumulation ratesVery slow accumulation rates Fig. 4.15a
  28. 28. ManganeseManganese nodulesnodules Fig. 4.26
  29. 29. Cosmogenous marineCosmogenous marine sedimentssediments  Macroscopic meteor debrisMacroscopic meteor debris  MicroscopicMicroscopic iron-nickel and silicateiron-nickel and silicate spherulesspherules  TektitesTektites  Space dustSpace dust  Overall, insignificant proportion ofOverall, insignificant proportion of marine sedimentsmarine sediments
  30. 30. Microtektites - extraterrestrial
  31. 31. Mixtures of marine sedimentsMixtures of marine sediments  Usually mixture of different sedimentUsually mixture of different sediment typestypes  For example, biogenic oozes canFor example, biogenic oozes can contain up to 70% non-biogeniccontain up to 70% non-biogenic componentscomponents  Typically one sediment typeTypically one sediment type dominates in different areas of thedominates in different areas of the sea floorsea floor
  32. 32. Distribution of neritic and pelagic marineDistribution of neritic and pelagic marine sedimentssediments Fig. 4.19
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