Emergent Marine Record and Paleoclimate of the Last Interglaciation along the Northwest Alaskan Coast

摘要: The last interglacial high sea-level stand, the Pelukian transgression of isotope substage 5e, is recorded along western and northern coasts Alaska by discontinuous but clearly traceable marine terraces coastal landforms up to about 10 m altitude. stratigraphy indicates that sea level reached this altitude only once during cycle. From type area at Nome, St. Lawrence Island in Bering Sea, eastern limit Beaufort deposits contain extralimital faunas indicating waters were warmer than present. Amino acid ratios molluscs from these decrease north toward Barrow, consistent with modern regional temperature gradient. Fossil assemblages Nome suggest winter sea-ice was Strait, least 800 km its present position, Sea perennially ice-free. Microfauna sediments recovered boreholes indicate Atlantic water may have been on shallow Shelf, suggesting Arctic Ocean not stratified cover perennial for some period. In regions Alaska, spruce woodlands extended westward beyond their range Coastal Plain, groves entered upper Colville River basin. Flaxman Member Gubik Formation Alaskan Plain deposited 5a records breakup an intra-stage 5 ice sheet over northwestern Keewatin.