HR: 0830h
AN: PP51B-0932    [PDF]
TI: The Link Between Eolian Flux, Paleoproductivity, Microfossil Preservation, and the Global Climate
AU: * McCarthy, F M
EM: francine@craton.geol.brocku.ca
AF: Brock University, 500 Glenridge Avenue, St. Catharines, ON L2S 3A1 Canada
AB: Most of the terrigenous material that reaches the abyssal mid-latitude western North Pacific Ocean is wind-transported because the abyssal plains are isolated from the Asian continental margin by submarine trenches. Eolian flux is favored by continental aridification and by an increase in wind strength- i.e. by geologic changes like Himalayan uplift as well as by astronomic (Milankovitch) parameters that promote glaciation. Our data from several ODP sites show that phytoplankton blooms (inferred from dinoflagellate cyst concentrations) were driven by enhanced eolian flux of limiting nutrients (inferred from the concentration of pollen and embryophyte spores) during the late Cenozoic. The increased particle sinking rate- a nonlinear function of terrigenous and biogenic particle flux- resulted in rapid sedimentation in the abyssal western North Pacific Ocean over short intervals ~5, 3.5, 3, 2.5, 1.6. 0.8, and 0.4 Ma. Carbon burial was enhanced as the rapid sedimentation of fine particles protected oxidation-susceptible organic-walled microfossils (palynomorphs) like "round-brown" protoperidiniacean dinoflagellate cysts from oxidation and highly soluble calcareous planktonic foraminifera from dissolution. Based on the ages of enhanced burial events and on first-order calculations of organic and inorganic carbon in these palynomorph-rich calcareous sediments, we suggest that the sequestration of CO2 over a large area of the abyssal Pacific Ocean may have weakened the greenhouse effect sufficiently to explain the sudden cooling events in the Plio-Pleistocene record.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 1600 GLOBAL CHANGE (New category)
DE: 3022 Marine sediments--processes and transport
DE: 3030 Micropaleontology
DE: 4855 Plankton
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting