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Award ID contains: 2114631

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  1. (, NSF Arctic Data Center)
    The Camp Century ice core, collected in 1966 from northwestern Greenland, recovered 3.44 meters of sub-glacial sediment from below nearly 1400 meters of ice. After drilling, the sediment was cursorily investigated and then misplaced for decades. This data set provides water isotope data from pore waters in the sediment, which reflects climate conditions when that sediment was exposed at the surface, about 400,000 years ago. 
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  2. ; ; ; ; ; ; ; ; ; ; et al (, Proceedings of the National Academy of Sciences)
    The persistence and size of the Greenland Ice Sheet (GrIS) through the Pleistocene is uncertain. This is important because reconstructing changes in the GrIS determines its contribution to sea level rise during prior warm climate periods and informs future projections. To understand better the history of Greenland’s ice, we analyzed glacial till collected in 1993 from below 3 km of ice at Summit, Greenland. The till contains plant fragments, wood, insect parts, fungi, and cosmogenic nuclides showing that the bed of the GrIS at Summit is a long-lived, stable land surface preserving a record of deposition, exposure, and interglacial ecosystems. Knowing that central Greenland was tundra-covered during the Pleistocene informs the understanding of Arctic biosphere response to deglaciation. 
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  3. ; ; ; ; ; ; ; ; ; ; et al (, Science)
    Past interglacial climates with smaller ice sheets offer analogs for ice sheet response to future warming and contributions to sea level rise; however, well-dated geologic records from formerly ice-free areas are rare. Here we report that subglacial sediment from the Camp Century ice core preserves direct evidence that northwestern Greenland was ice free during the Marine Isotope Stage (MIS) 11 interglacial. Luminescence dating shows that sediment just beneath the ice sheet was deposited by flowing water in an ice-free environment 416 ± 38 thousand years ago. Provenance analyses and cosmogenic nuclide data and calculations suggest the sediment was reworked from local materials and exposed at the surface <16 thousand years before deposition. Ice sheet modeling indicates that ice-free conditions at Camp Century require at least 1.4 meters of sea level equivalent contribution from the Greenland Ice Sheet. 
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