Julie Brigham-Grette, Professor

Dept of Geosciences, University of Massachusetts, Amherst, MA 01003

Research Interests:

Stratigraphy, geochronology, and climate history of glacial, marine, and lacustrine sediments across the Arctic as archives of past climate; specific interests include the paleogeography and history of Beringia, the sea level history of the Bering Straits and circumarctic teleconnections on the ocean/land/ atmosphere system, the climate evolution of the arctic over the last 5 million years; special interests are in amino acid geochronology using fossil mollusks. First worked along the Arctic coast from Barrow to Pt. Lay in 1980 and 1981.

Lloyd Keigwin, Senior Scientist

Woods Hole Oceanographic Institution, Woods Hole, MA 02543

Research Interests:

Climate and ocean history using oxygen and carbon isotopes in foraminifera, biostratigraphic techniques, and sediment lithology; specific interests include: circulation history of the pre-Quaternary ocean on orbital time scales; history of climate and ocean circulation change in the Holocene and late Pleistocene on millennial and century time scales; relationship between the ecology of living benthic foraminiferal species and their stable isotope composition.

Neal Driscoll, Associate Professor

Scripps Institution of Oceanography, University of California-

San Diego, San Diego, CA 92121-2460

Research Interests:

Stratigraphy is the tape recorder of Earth history. Nevertheless, the fidelity with which stratigraphy records the dynamic processes of sediment erosion, transport, accumulation and preservation is still incompletely understood. Although these processes can be examined from many perspectives, my research has focused on: (1) unconformity generation and stratigraphic development in tectonically active settings, and (2) sediment input and dispersal in evolving sedimentary basins and along continental margins.

Effects of Changes in Sea Level Across Beringia

Sea Level at LGM

~12,000 ybp

~10,000 ybp

Modern Sea Level

During the last glacial maximum sea level was lowered by ~125m.The size of Beringia increased dramatically, and the flow of fresher, nutrient rich Pacific water into the Chukchi Sea was cut off due to the resulting emergence of the Bering Strait. These conditions affected the Beringian climate, the fresh water budget of the Arctic Ocean, and ocean circulation as they changed through time, but exactly how is not understood. Controversies exist as to whether the Bering Land Bridge was dominated by moist or dry tundra as large mammals and man migrated between continents. This lack of understanding is partly due to the fact that relative sea level in Beringia is likely to have differed from eustatic sea level as a result of tectonic and possible glacio-eustatic effects. Additionally, very little high-resolution proxy data exists for sea surface conditions in the Bering and Chukchi Seas.

Proposed Bering Sea Core Sites

PROPOSED WORK

It is clear that the ocean exerts tremendous control over Beringian climate through its temperature, salinity, ice extent, albedo, and sea level. Yet the history of these variables in the Bering and the Chukchi Seas is not known well enough to integrate with the evidence for terrestrial climate change. Our proposed work will recover sediment cores and geophysical data that will provide new constraints on the spatial and temporal variability of climate in the northern Pacific region, the Bering and Chukchi Seas, and Beringia. This approach will yield data necessary to understand the important linkages within Beringia as well as its importance in Earth’s climate system.

Area of Proposed Coring in Chukchi Sea

web page created June 12, 2002