HR: 0830h
AN: PP11A-0220    [PDF]
TI: The Deglaciation in the Bering Sea: New Results From High Accumulation Rate Cores
AU: * Cook, M S
EM: meacook@mit.edu
AF: MIT-WHOI Joint Program in Marine Geology \& Geophysics, Mail Stop #24, Clark South 275B, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 United States
AU: Keigwin, L D
EM: lkeigwin@whoi.edu
AF: Department of Marine Geology \& Geophysics, Woods Hole Oceanographic Institution, Mail Stop #8, McLean 207A, Woods Hole, MA 02543 United States
AB: Previous work in the Bering Sea region is difficult to integrate with data from other parts of the world because of the low sediment accumulation rates and low carbonate preservation endemic to the Pacific. In summer, 2002, we collected new sediment cores from 3 regions of the Bering Sea from the USCGC Healy. Based on lithologic and isotopic correlation, preliminary data show that accumulation rates are high (10 to 100\,cm/ky). These cores will provide a stratigraphic and chronologic framework for studying the extent and timing of climate events in the region over the past $\sim$60\,ky. The deglaciation in the Bering Sea was marked by an abrupt freshening of surface water, as recorded in planktonic foraminifer and diatom $\delta^{18}$O. The origin of this freshwater is unknown. One possible source is discharge from the Yukon River, though Alaska is not thought to have been highly glaciated during the last glacial maximum. Another possible source is the newly opened Bering Strait, though the timing of the submergence of the strait is poorly constrained. Today, flow through the strait is primarily northward, though in the past, with different boundary conditions, the flow could have been reversed. All of our Bering Sea cores contain this deglacial sequence, which is characterized by high %carbonate, low %opal, and high organic carbon, and can be correlated with other cores from the open North Pacific. In our oxygen minimum zone-depth cores, this sequence is often laminated, not just during the deglaciation, but in the early Holocene and episodically through marine isotope stage 3. This is analogous to the lamination found in Santa Barbara Basin and the Gulf of California cores.
DE: 3030 Micropaleontology
DE: 4207 Arctic and Antarctic oceanography
DE: 4223 Descriptive and regional oceanography
DE: 4243 Marginal and semienclosed seas
DE: 4267 Paleoceanography
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting