HR: 0830h
AN: PP51C-0939    [PDF]
TI: Beringian Sea Level and Marine Climate History: Investigations into Regional \& Global Impacts
AU: * Brigham-Grette, J
EM: juliebg@geo.umass.edu
AF: University of Massachusetts-Amherst, Department of geosciences, Amherst, MA 01003 United States
AU: Driscoll, N
EM: ndriscoll@ucsd.edu
AF: Scripps Institution of Oceanography, Geaosciences Research Division, La Jolla, CA 92093 United States
AU: Keigwin, L
EM: lkeigwin@whoi.edu
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543 United States
AU: Lundeen, Z
EM: zlundeen@geo.umass.edu
AF: University of Massachusetts-Amherst, Department of geosciences, Amherst, MA 01003 United States
AU: Hill, J
EM: jchill@ucsd.edu
AF: Scripps Institution of Oceanography, Geaosciences Research Division, La Jolla, CA 92093 United States
AU: Cook, M
EM: meacook@mit.edu
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543 United States
AU: Donnelly, J
EM: jdonnelly@whoi.edu
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543 United States
AB: Glacial-interglacial cycles have imposed on the Bering Strait region some of the most radical changes in paleogeography documented in the Northern Hemisphere. Only 20,000 years ago during the last glaciation when sea level was about 130 m below present, the Bering Land Bridge separated the deeper Bering Sea and North Pacific Ocean from the Arctic Ocean by more than 1000 kilometers of herb-dominated tundra. Missing from existing literature are studies of how the Bering and Chukchi seas participate in controlling Beringian and global climate. Fluctuations in sea level caused the rapid migration of shorelines changing gradients in temperature and moisture with considerable downwind effects based on regional terrestrial records. The greatest east-west heterogeneity across Beringia occurred during warm (flooded) or warming (partially flooded) periods of late Pleistocene summers, when the cool maritime influence bifurcated the relatively warm continental interior. Oceanographic changes were also radically influenced by changes in sea level across the Bering Straits that regulated the northward flow of Pacific waters into the Arctic Ocean and North Atlantic. Especially important in our collective research is an understanding of how the flow of water through the Bering Strait may have influenced documented changes in thermohaline circulation in the North Atlantic (e.g., Younger Dryas) by changing the flux of fresher Pacific water into the Arctic Ocean. On board the USCGC Healy in the summer of 2002, we collected from -2800m to -50 m water depth, a set of nearly 100 different marine cores measuring over 500 meters in total length. Some are up to 21 meters long, from -1300 m water depth, the longest cores taken in this part of the western Arctic. Specific cores appear to hold a high-resolution record of the deglacial and Holocene history in this region and a few of the cores likely contain sediments back to nearly 140,000 yrs BP. We also learned that the stratigraphic architecture of channel cut and fill across the Chukchi shelf is very complex with an outstanding record of repeated phases of sea level rise and fall. This complexity and related paleoceanographic implications will likely drive the direction of our future research. A series of related posters in this session highlight initial results from this ongoing project.
DE: 4267 Paleoceanography
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting