The extent and timing of Pleistocene ice sheets over northern Eurasia remain unresolved. The views range from full coverage of the Barents and Kara Seas by a marine-based ice sheet to land-based ice-cap systems on adjacent archipelagos. The heart of the divergence on the nature of last glaciation in northern Eurasian is uncertainty on ice sheet thickness over Novaya Zemlya and extension into Siberia. In collaboration with the Murmansk Institute of Marine Biology we propose to initiate basic glacial-geologic, stratigraphic and geochronologic studies to provide new field data to independently evaluate the limits and timing of Weichselian glacial and deglacial events on Novaya Zemlya, Russia. Field research will focus on three field areas on northern Novaya Zemlya, where ice-free forelands contain abundant raised marine and glacial features. We plan to use the following approaches to decipher the record of Quaternary glaciations on Novaya Zemlya: 1) High resolution (10-m pixels) SPOT satellite imagery will be used to evaluate large scale sea-level, glacial erosional and depositional features (moraines) that may not readily be discernible in the field. 2) Documentation of the timing and rate of the glacial-isostatic response by radiocarbon dating of subfossils included in raised beaches of known elevation. 3) A study of the stratigraphy and sedimentology of superimposed Quaternary sediments in cliff sections. Particular attention will be given to the recognition of glacial damicts and unconformities, and the collection of micro-and macro-fauna for paleoenvironmental assessment and chronologice control. Provenance studies of clasts from glacial diamicts and fabric analysis should provide new information on glacial source area. 4) Age control for the latest glacial/sea level events will be derived from conventional and AMS radiocarbon dating of included marine subfossil and driftage. The number and timing of older events will be constrained by amino acid epimerization analyses of mollusks using L-isoleucine/D-alloisoleucine ratios and higher resolution D/L aspartic acid ratios. Numeric age will be determined by luminescence geochronometry on the fine-grained fraction (4-11(m) from raised sublittoral sediments. 5) Integration of field data with isostatic and glaciological modeling to provide insight into glacier thickness, position of ice divides, domes and streams and response to sea level rise. Results from this study are important for evaluating if ice sheets on northern continental shelves responded synchronously, if the Barents, Kara and Norwegian Seas deglaciated prior to 14 ka ago, and the effect of Eurasian ice sheets on North Atlantic thermohaline circulation. This field-based research will provide new data on Weichselian glacier geometry in the Russian Arctic, where little currently exists, which is a critical boundary condition for evolving global climate models.
