Pacific Water Mass Circulation During the Paleogene: Initial Results from Pacific Equatorial Age Transect (PEAT) Sediment Cores
Abstract
During the Pacific Equatorial Age Transect (PEAT), comprised of Integrated Ocean Drilling Program (IODP) Expeditions 320/321, eight sediment cores were drilled over progressively younger oceanic basement ages. This strategy enabled the recovery of sediments deposited beneath the equatorial high productivity zone throughout key intervals during the Cenozoic. Furthermore, known rates of Pacific seafloor subsidence combined with new sediment accumulation rates from the PEAT cores provide tightly constrained seafloor paleodepths. In our study we measured neodymium (Nd) isotope compositions and rare earth element (REE) compositions from fossil fish teeth in Paleogene sections of Sites U1331, U1332, and U1333 at a sampling resolution of <500kyr. Paleodepths of these sites ranged from 2750 to 4000 m. Fossil fish teeth preserve the Nd isotopic composition of bottom waters at the time of deposition, which contain information about the source region of the water mass. Thus, this dataset contains information about the vertical water mass composition in the Pacific during the Paleogene. Our preliminary results reveal significant secular variability in the Nd isotopic composition of Pacific water masses (on the order of 1.5 ɛNd units), which have implications for water mass mixing, wind-blown terrigenous inputs to the Pacific basin, and inter-basin water mass exchange.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMPP13A1797S
- Keywords:
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- 1050 GEOCHEMISTRY / Marine geochemistry;
- 4924 PALEOCEANOGRAPHY / Geochemical tracers;
- 9355 GEOGRAPHIC LOCATION / Pacific Ocean