Ocean chemistry and deep-sea sediments

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Preservation of pelagic carbonatesedimentsBiological productivity of calcareous oozedominate in lower productivity zones whileforaminiferal oozes increase faster in highproductivity zones.CO 2 plays a major role in carbonatepreservation. First note that CO 2 is moresoluble in cold than in warm water. Therefore,higher CO 2 concentrations in colder watercause more carbonate dissolution (polarwaters have no or only minor amounts ofcarbonate)!Second, CO 2 combined with water produces aweak acid. It produces hydrogen andbicarbonate ions:Typical profile of sum (marked left) of total dissolvedinorganic carbon Σ CO 2 . CO 2 is removed from solution insurface waters by photosynthesis. It is returned tosolution in deep water as organic matter is decomposed.CO 2 gas + H 2 O = H 2 CO 3 = H + + HCO 3-HCO 3- = H + + CO 32-
Preservation of pelagic carbonatesedimentsΣCO 2 is total dissolved inorganic matter, as this sum increases, so does the ratio of bicarbonate tocarbonate ions. CO 2 gas + H 2 O = H 2 CO 3 = H + + HCO 3- ; HCO 3- = H + + CO 32-[H + ] = K [HCO 3- ]/[CO 32-]The terms are in molar concentrations and K is the equilibrium konstant.• If H + increases, then there are more hydrogen ions in the water, and the water becomes more acid(pH decreases)!• If H + decreases, then the ΣCO 2 decreases, and the water becomes less acid (pH increases)!• Dissolution of calcium carbonate skeletons occurs where ΣCO2 is high that means the water ismore acid. We can use two equations for the carboanet dissolution.1. CaCO 3 + H + Ca 2+ + HCO 32-2. CaCO 3 Ca 2+ + CO 32-
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Ocean chemistryanddeep-sea sediment
Page 3 and 4: 1. Introduction - Type of deep-sea
Page 5 and 6: Biogenic sedimentsBeneath high-prod
Page 7 and 8: Sediments in the open ocean are cal
Page 9: Carbonate oozePhytoplankton - Cocco
Page 12 and 13: Gastropod molluscs- pteropodsAragon
Page 15 and 16: Cold-water coral reefsExamples of d
Page 17 and 18: Zooplankton - Radiolaria
Page 20 and 21: Calcareous and Siliceousmicrofossil
Page 22 and 23: Nutrients and δ 13 C13δ C =1313(
Page 24: Modern and glacial Atlantic interme
Page 28 and 29: Clay mineralsKaolinite is formed by
Page 30: Turbidites
Page 33: LGM ice sheet extentIRD input
Page 37: Sedimentation rates
Page 40 and 41: 2. Chemical cycles in the Oceans
Page 42 and 43: Steady state oceanWhat do the nutri
Page 44 and 45: Dissolved constituents arecoming fr
Page 46 and 47: A large part of the decomposed mate
Page 48 and 49: Phosphate distribution in oceansat
Page 50 and 51: Upper right: Nutrients areenriched
Page 52 and 53: 3. Accumulation of pelagic biogenic
Page 56 and 57: 1 2Ca 2+ concentrations inseawater
Page 58 and 59: Preservation of pelagic carbonatese
Page 60 and 61: The Lysoclineand the Carbonate Comp
Page 62 and 63: SUMMARY:• The solubility of calci
Page 64 and 65: Transport and deposition of dissolv
Page 66 and 67: Water mass stratification hinderpar
Page 68 and 69: Sedimentation ratesdetermine time r
Page 70: What causes the Gulfstream?Circulat
Page 73 and 74: • Transport of sediments to the o
Page 75 and 76: Sediment drifts• A major step in
Page 78 and 79: Sediment waves or mud waves
Page 81 and 82: Bottom currents and sediment drifto
Page 83 and 84: Downslope transport by gravitation
Page 85 and 86: IntroductionTwo factors are crucial
Page 87 and 88: Tsunami deposits on landIcelandStor
Page 89 and 90: Continental margin slope failuresDo
Page 91 and 92: Slide headwalls ArcticShelf
Page 93 and 94: Rotational slumps/faults at Stornes
Page 95 and 96: Glide planes and sediment typesThe
Page 97 and 98: Debris flow
Page 101 and 102: Downslopesedimenttransport•TMF•
Page 103 and 104: Sidescan Sonar and Seismic Images
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Continental margin slope failuresDo
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Solsikke - Seabed topographySlide d
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Key questions for the understanding
Page 111 and 112:
Slope angles - Section B
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Summary•Geological, morphological
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Mienert, J. & Weaver, P.P.W., eds.,
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Ice margin 18 000 BPGrand BanksSour
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Scotian Slope multibeamDownloaded f
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From Pickrill et al., 2001. OTC pap
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Upper and middle slope canyonseast
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Single channel airgun profile over
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Slope canyon incisions and sediment
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Diagenesisof sediments after burial
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Ocean chemistry and deep-sea sediments

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