9412262 THOMPSON Ice cores drawn from glaciers provide an important source of information about changes in climate, vegetation, and other phenomena over tens of thousands of years. Analyses of oxygen isotopes can generate proxies for temperature, and analyses of soluble and insoluble aerosols can provide indications of wind strength and direction, volcanic activity, and drought. Measurement of the thickness of annual ice layers yield valuable information about precipitation patterns. Pollen contained within ice cores has not been studied as extensively, but these fine particles offer great potential as sources of information about past patterns of vegetation. This collaborative research project will extract a long-term pollen record with a high temporal resolution from ice cores extracted from the Dunde Ice Cap in western China. This pollen record will supplement other climate proxy data to provide a detailed regional history of changes in the climate and related variables over the last 100,000 years. Special emphasis will be placed on the use of these data to examine vegetational responses to monsoon circulation changes induced by changes in the Earth's orbit. Analyses also will be undertaken to consider vegetational responses to cooling during the "Little Ice Age" and to greenhouse gas-induced warming during the late Pleistocene and Holocene periods. This project will provide valuable new data to facilitate the reconstruction and analyses of climatic changes over the last 100,000 years. Because subtropical glaciers like the Dunde Ice Cap contain far more pollen than do glaciers at higher latitudes, they permit examinations with relatively great temporal precision of changing patterns of climate and vegetation. They also provide valuable sources of data regarding current rates of change, and these data can be used to help validate a number of different climatic models. ***
