Missing the forests for the trees: classical Pleistocene multiproxy records versus new geochemical tracers
Abstract
We present traditional paleoceanographic records from five DSDP/ODP cores ranging from 58.1N (Site 646), off W. Greenland to 41.5N (Site 607)on the Mid Atlantic Ridge, MAR(Fig. 1). The suite of proxies includes: grain size, clay mineral abundance, IRD and its source rock palynomorphs; foraminifera & their stable isotopes, SSTs and SSTw, coccoliths, dinocyst assemblages, SST and PP, and pollen markers of terrigenous carbon influx. Inter-site comparison shows major latitudinal shifts in intensity of glacial cooling cycles beginning in the Mid-Pleistocene (MIS 13-11), accompanied by floral and faunal re-organizations, shifts in carbon production and burial, and IRD sources. This reorganization clearly correlates with long-term shifts in Milankovitch orbital parameters. We compare these results with three sites where new proxies were used to reinterpret paleoceanography for the last 4 glacial cycles: Grand Banks site CH69-K09 (near site HU89-007-3) and MAR sites CHN82-2040 and IODP U1313 (re-occupation of DSDP site 607). New Fe and Ti markers of sediment remobilization confirm and refine our traditional palynological data. However, new interpretations of warmest and coldest conditions based on Mg/Ca-SSTs need to be re-evaluated against the old foraminifera-based SSTs from northern sites closer to icesheet margins, and in the context of updated, more precise surface current data.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFMPP31B1323M
- Keywords:
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- 0473 BIOGEOSCIENCES / Paleoclimatology and paleoceanography;
- 1050 GEOCHEMISTRY / Marine geochemistry