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Geoscience Systems: Modeling oxygen and carbon dioxide over the past 600 million years

Geoscience Systems: Modeling oxygen and carbon dioxide over the past 600 million years. Robert A. Berner Yale University December 20, 2010. Short Term Carbon Cycle. Marine photosynthesis. Ocean C. Atmosphere C. Gas exchange. Terrestrial Respiration. Terrestrial

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Geoscience Systems: Modeling oxygen and carbon dioxide over the past 600 million years

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  1. Geoscience Systems: Modeling oxygen and carbon dioxide over the past 600 million years Robert A. Berner Yale University December 20, 2010

  2. Short Term Carbon Cycle Marine photosynthesis Ocean C Atmosphere C Gas exchange Terrestrial Respiration Terrestrial Photosynthesis Degassing River transport Litter fall Root decay Calcification Soil C Biota C Marine respiration

  3. Carbon Masses • FORM 1018 moles C • Sedimentary rock CaCO3 3000 • Sedimentary rock CaMg(CO3)2 2000 • Sedimentary organic carbon 1250 • Oceanic HCO3- + CO3-- 2.8 • Soil organic carbon 0.3 • Life 0.04 • Atmospheric CO2 0.056

  4. Long Term Carbon Cycle Over millions of years HCO3-

  5. Long Term Carbon Cycle Rock Organic C Rock Carbonate C Organic C Burial Carbonate C Burial Carbonate C Weathering Organic C Weathering Ocean Atmosphere Biota Soils C Volcanic,Metamorphic, Diagenetic, Degassing Volcanic, Metamorphic, Diagenetic Degassing

  6. Weathering plus Sedimentation • CaSiO3 + 2 CO2 + H2O ---> Ca++ + 2HCO3- + SiO2 • Ca++ + 2HCO3- ---> CaCO3 + CO2 + H2O • Overall Silicate Reaction CO2 + CaSiO3 ---> CaCO3 + SiO2

  7. CO2 Reactions Weathering and sedimentation CO2 + (Ca,Mg)SiO3 ---> (Ca,Mg)CO3 + SiO2 Metamorphism/volcanism/diagenesis (Ca.Mg)CO3 + SiO2 ---> CO2 + (Ca,Mg)SiO3 Organic matter burial CO2 + H2O ---> CH2O + O2 Organic matter weathering & metamorphism/volcanism/diagenesis CH2O + O2 --->CO2 + H2O

  8. Jacques Ebelmen 1814-1852 Founder of long term C and S cycles

  9. Mountain Building & Erosion CO2 System = Negative response Solar Radiation Weathering Ca-Mg Silicates Ca-Mg carbonate burial +/- Continental drift A B Climate (T + pptn) +/- CO2 Land Plants Weathering Org C Organic C sed. Burial Long Term Volc/Met/Diag Degassing Long Term

  10. Surficial System C Mass Balance Fwc + Fmc + Fwg + Fmg = Fbc + Fbg dcFwc + dcFmc + dgFwg + dgFmg = dbcFbc + dbgFbg w = weathering; m= metamorphism: b= burial c = carbonate : g = organic matter d = measure of 13C/12C

  11. Controls on Atmospheric O2 Organic Matter Burial and Weathering CO2 + H2O CH2O + O2 Sedimentary Pyrite Formation and Weathering 2Fe2O3 + 16 Ca++ + 16HCO3- + 8SO4-- 15O2 + 4FeS2 + 16 CaCO3 + 8H2O

  12. Isotope Mass Balance Rock Carbonate C Rock Organic C Org C Burial (+O2) CaCO3 Burial Weathering Weathering ( - O2) Oceanic Carbon and Sulfur Volc/met gas oxidation (-O2) Volc/met gas Weathering ( - O2) Weathering Rock Sulfate S Rock Sulfide S Sulfide Burial (+O2) CaSO4 Burial

  13. CaSO4 dissolution SO4

  14. Isotope Feedback for Atmospheric O2 Sulfur Isotope Fractionation aS Carbon Isotope fractionation aC O2 Organic C burial Pyrite S burial Fborg Fbpyr = K/a

  15. Rapid Recycling and O2 Burial of Organic C Pyrite S Weathering of Organic C Pyrite S Uplift Sea level drop O2

  16. Phanerozoic Oxygen

  17. Geological Forcing and Oxygen Continental Relief and Erosion Volc-Met- Diagen Degassing Weathering Phosphorus Weathering FeS2 Weathering Organic C FeS2 Burial O2 Organic C sed. Burial

  18. Animal Gigantism

  19. Modern dragonfly

  20. Plants, Fires and Oxygen Feedbacks Fires Erosion Charcoal O2 Land Plants Organic C sed. Burial

  21. P Tr

  22. Permo-Triassic Extinction feedbacks h Plant-derived Organic burial CO2 In air i a O2 in air g b Volcanism Land plants Ocean Temp. j f O2 In sea H2S In air c Ocean stratification & anoxicity k e d Sulfate reduction

  23. EFFECTS OF RISE AND SPREAD OF LARGE LAND PLANTS 1. Atmospheric CO2 removal by increased silicate weathering 2. Additional CO2 removal by increased burial of organic matter 3. Extra O2 added to atmosphere by increased organic burial 4. CO2 drop induced global cooling via the greenhouse effect 5. Elevated O2 induced animal gigantism

  24. Oxford University Press, 2004

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