HR: 1340h
AN: PP33A-0911    [Abstracts]
TI: Differentiation of Cenozoic Eolian Dust Sources in the Eastern Pacific by Nd-Sr-Pb Radiogenic Isotopes
AU: * Stancin, A M
EM: astancin@umich.edu
AF: Department of Geological Sciences, University of Michigan 2534 C.C. Little Building, Ann Arbor, MI 48109-1063 United States
AU: Gleason, J D
EM: jdgleaso@umich.edu
AF: Department of Geological Sciences, University of Michigan 2534 C.C. Little Building, Ann Arbor, MI 48109-1063 United States
AU: Owen, R M
EM: rowen@umich.edu
AF: Department of Geological Sciences, University of Michigan 2534 C.C. Little Building, Ann Arbor, MI 48109-1063 United States
AU: Rea, D K
EM: davidrea@umich.edu
AF: Department of Geological Sciences, University of Michigan 2534 C.C. Little Building, Ann Arbor, MI 48109-1063 United States
AU: Moore, T C
EM: tedmoore@umich.edu
AF: Department of Geological Sciences, University of Michigan 2534 C.C. Little Building, Ann Arbor, MI 48109-1063 United States
AU: Hendy, I
EM: ihendy@umich.edu
AF: Department of Geological Sciences, University of Michigan 2534 C.C. Little Building, Ann Arbor, MI 48109-1063 United States
AU: Blum, J D
EM: jdblum@umich.edu
AF: Department of Geological Sciences, University of Michigan 2534 C.C. Little Building, Ann Arbor, MI 48109-1063 United States
AU: Klaue, B
EM: bklaue@umich.edu
AF: Department of Geological Sciences, University of Michigan 2534 C.C. Little Building, Ann Arbor, MI 48109-1063 United States
AB: DSDP, ODP and piston core samples from the eastern Pacific provide a temporal and spatial context for mapping changing sources of eolian dust during the Cenozoic Era (65 Ma to present). We examined core sites from ODP Sites 469, 495, 853, 885/886, DSDP Sites 32, 319, 320, and piston core sites EW9709-01, 07 for Pb, Sr and Nd isotopic provenance. Isotopic analyses were performed on the $<$63 micron extracted detrital component following reductive cleaning to remove all authigenic and biogenic components. Downcore comparison of continental margin sites with those dominated by pelagic clays from north and south of the equator was facilitated by factor analysis using two programs. Multivariate factor analysis was performed with both CABFAC and Minitab. Three factors were identified and accounted for 98.4% of the variance. Factor 1 (epsilon Nd and Pb 207/206) defines the dominant late Cenozoic Asian dust source and accounts for 44.1% of the variance. Factor 2 identifies a South American dust source based on $^{87}$Sr/$^{86}$Sr and Pb 206/204, 208/204 and 207/204 and accounts for 36.5% of the variance. Factor 3 identifies a North American dust source ($^{87}$Sr/$^{86}$Sr, Pb 208/206, and Pb 207/206) and accounts for 17.8% of the variance. We conclude that in the eastern Pacific, late Cenozoic Asian dust sources can be quantitatively differentiated from both North American and South American continental sources. We are attempting to extend this record back to 65 Ma, with the ultimate goal being to reconstruct long-term Cenozoic atmospheric circulation and wind patterns across major climate transitions.
DE: 4835 Inorganic marine chemistry
DE: 4267 Paleoceanography
DE: 3022 Marine sediments--processes and transport
DE: 1040 Isotopic composition/chemistry
DE: 1050 Marine geochemistry (4835, 4850)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting