Collaborative Research: Millennial Scale Arctic Climate Change for the last 3.6 My: Scientific Drilling at Lake El'gygytgyn, NE Russia

点击翻译按钮获取中文摘要

The sedimentary record of Lake El'gygytgyn, an impact crater in northeastern Siberia, has become a focus for paleoclimatic research and is now considered a high-priority, world-class target for drilling by the International Continental Drilling Program (ICDP). Sediment cores retrieved from the deepest part of the lake (170 m) in 1998 and 2003 revealed a basal age of ~ 250 and nearly 300 ka, and reproducibly demonstrated the sensitivity of the lake to climatic change across NE Asia at millennial timescales. These cores are the oldest terrestrial Arctic cores yet retrieved. This grant will support acquiring deeper cores in spring 2008 through to bedrock. The cores could potentially yield a record of Arctic climate dating back to over 3 My ago. Seismic measurements show 400 m of sediments overlying the impact breccias. This grant is the U.S. contribution to a multi-national effort to retrieve the cores and carry out subsequent scientific research, joining contributions from the ICDP, the Canadian, German and Russian governments.Intellectual merit: The goal is to collect and interpret the longest time-continuous record of climate change in the terrestrial Arctic and compare this record with those from lower latitude marine and terrestrial sites to better understand hemispheric and global climate change. Coring objectives include 2 replicate overlapping cores at 2 sites near the deepest part of the lake. One additional land-based core on lake sediments now overlain by frozen alluvial sediments will allow a better understanding of sediment supply to the lake. These cores will provide a unique Arctic record capturing the mechanisms and dynamics of glacial/interglacial and millennial-scale change for comparison with other long records from the oceans. This will allow scientists to evaluate and model systemic teleconnections and leads/lags relative to insolation forcing during periods of both 41 ka and 100 ka cycling. This record will provide insight as to whether rapid change events identified during the last glacial cycle are typical of earlier glacial periods. This core will allow us to address questions concerning the evolution and mode of Arctic climate change via the transition from the warm middle Pliocene to the onset of the first major Northern Hemisphere glaciation. The cores will provide a record of the regional sensitivity of the N E Asian Arctic to millennial-scale abrupt change and interglacial warmth detected in the timeframe of the EPICA ice cores, long Asian loess and lake records, and marine records.Broader impacts: This work will help us understand the background of natural variations in Arctic climate so that modern changes can be understood within that context. As this work will occur during the International Polar Year (IPY), the retrieval of a unique Arctic core will be especially timely. International sharing of research builds trust and mutual respect between our nations and individuals, but also between political bodies and institutions in Moscow and the more remote regions of Russia. This proposal will support graduate and undergraduates at 4 U.S. institutions. A large portion of the outreach efforts will be internet-based, incorporating the latest interactive 3D GIS and terrain visualization technology, video, and real-time interactions with educators in the field, all tying this project into the IPY.