Accession Number : ADP007351

Title :   Deglaciation and Latest Pleistocene and Early Holocene Glacier Readvances on the Alaska Peninsula: Records of Rapid Climate Change Due to Transient Changes, in Solar Intensity and Atmospheric CO2 Content?

Corporate Author : ALASKA UNIV FAIRBANKS

Personal Author(s) : Pinney, DeAnne S. ; Beget, James E.

Report Date : MAR 1992

Pagination or Media Count : 7

Abstract : Geologic mapping near Windy Creek, Katmai National Park, identified two sets of glacial deposits postdating late-Wisconsin Iliuk moraines and separated from them by volcaniclastic deposits laid down under ice-free conditions. Radiocarbon dating of organic material incorporated in the younger Katolinat till and in adjacent peat and lake sediments suggests that alpine glaciers on the northern Alaska Peninsula briefly expanded between ca. 8500 and 10,000 years B.P. Stratigraphic relationships and radiocarbon dates suggest an age for the older Ukak drift near the Pleistocene-Holocene boundary between ca. 10,000 and 12,000 years B.P. We suggest that rapid deglaciation following deposition of the Iliuk drift occurred ca. 13,000-12,000 years B.P. in response to large increases in global atmospheric greenhouse gas content, including C02. Short-term decreases in these concentrations, as recorded in polar ice cores, may be linked with brief periods of glacier expansion during the latest Pleistocene and early Holocene. A transient episode of low solar intensity may also have occurred during parts of the early Holocene. Rapid environmental changes and glacial fluctuations on the Alaska Peninsula may have been in response to transient changes in the concentration of atmospheric greenhouse gases and solar intensity.

Descriptors :   *ALASKA, *GLACIERS, *PENINSULAS, *CLIMATE, *CARBON DIOXIDE, ATMOSPHERICS, BOUNDARIES, CORES, DEPOSITION, DEPOSITS, DRIFT, EXPANSION, GLACIAL DEPOSITS, GLOBAL, GREENHOUSES, ICE, INTENSITY, LAKES, MAPPING, MATERIALS, ORGANIC MATERIALS, PEAT, RADIOCARBON DATING, RESPONSE, SEDIMENTS, TRANSIENTS, WISCONSIN, SYMPOSIA, VOLCANOES.

Subject Categories : Geography
      Snow, Ice and Permafrost
      Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE