Paleoclimatic Studies of Closed-Basin Lakes in Great Basin of the Western U.S.

美国西部大盆地的第四纪地质在中纬度地区的冰河时期气候记录方面提供了很多信息。先前的研究表明，大陆气候可能以一种与海洋沉积物中记录的高纬度冰川反应截然不同的方式对天文（轨道）强迫做出反应。然而，与海洋领域的记录相比，陆地记录的数据库相当贫乏，对这两种记录进行严格的比较可能是我们了解更新世气候的关键。该项目的目的是重建过去35-40万年西部大盆地的古气候变化和水平衡。重建工作将利用最近同位素技术的一些重要发展，以及莫诺湖和欧文斯湖沉积物的及时地层学工作。这些进展使我们能够以前所未有的详细程度定量评估古降水/蒸发记录。使用的同位素工具为10Be/9Be比值、u系不平衡、818O和813C稳定同位素。

The Quaternary geology of the Great Basin of the Western U.S. has much to offer in term of ice age climate records on land in mid-latitudes. Previous works have shown that the continental climate may have responded to astronomical (orbital) forcing in a manner that could be quite different from the high-latitude glacial response recorded in marine sediments. However, the data base for land-based records is rather meager relative to that for the oceanic realm and a rigorous comparison between the two records may hold a key to our understanding of Pleistocene climates. The objective of this project is to reconstruct the paleoclimate variations and water balance of the Western Great Basin during the past 35-40 thousand years. The reconstruction will take advantage of some recent important developments in isotopic techniques and in time stratigraphic work on sediments of the Mono and Owens Lakes. These developments enable us to quantitatively assess the paleoprecipitation/evaporation records in unprecedented detail. The isotopic tools to be used are 10Be/9Be ratios, U-series disequilibrium, and stable isotopes 818O and 813C.