Global Change: COLLABORATIVE RESEARCH: Geologic & Pedologic Record of Climate and Vegetation in Pleistocene Palouse Loess, Pacific, Northwest

哥伦比亚高原帕卢斯黄土的五个地点，每个地点跨越过去75000年（最后一个冰期到现在的间冰期），将在暴露、描述和采样中绘制地图。这些站点的序列将形成一个从200毫米到700毫米降水，温暖到凉爽，灌木-草原到森林的生物气候样带。温度年代学、土壤地层学和热释光测年将提供地点之间的年代控制和相关性。蛋白石植物岩的稳定同位素地球化学和丰度以及土壤形成的碳酸钙的稳定同位素地球化学将提供有关植物覆盖、植物群落类型和温度随时间变化的信息。遗址地层学和微观形态（土壤显微镜）、古土壤的物理和化学性质将有助于解释黄土的退化和侵蚀循环、土壤的发育以及变化的植被和气候与土壤形成过程和景观演变的关系。古土壤和黄土磁化率的测量将成为检验中国黄土气候代理模型的关键。上述子项目将被综合成一个定量描述模型，描述过去75000年的5000至10000年时间片的变化。两个更长的地层剖面可追溯到公元前175000年，然后将进行采样和分析，使用相同的技术来重建第二次冰期-间冰期旋回的记录利用气候和植被变化的信息，量化区域范围内土壤学、沉积学和山坡地貌系统对这些变化的响应，进一步记录科迪勒冰盖活动的基于损失的代理记录，并测试几个气候代理记录。

Five sites in the Palouse Loess of the Columbia Plateau, that each span the last 75,000 yr (the last glacial cycle through the current interglacial), will be mapped in exposures, described, and sampled. The sequence of sites will form a bioclimatic transect from about 200 mm to 700 mm precipitation, warm to cool temperature, and shrub-steppe to forest. Tephrochronology, soil stratigraphy, and thermoluminescence dating will provide chronological control and correlation among sites. The stable isotope geochemistry and abundances of opal phytoliths and the stable isotope geochemistry of soil-formed calcium carbonates will yield information about fluctuations in plant cover, plant community type, and temperature through time. Site stratigraphy and the micromorphology (soil microscopy), physical, and chemical properties of paleosols will yield interpretations of loess aggradation and erosion cycles, of soil development, and of relationships of changing vegetation and climate to soil-forming processes and landscape evolution. Measurement of magnetic susceptibility of paleosols and loess will serve as a critical test of the climate proxy model developed from Chinese loess. The sub projects above will be synthesized into a quantitative descriptive model of change in 5,000 to 10,000 year time slices through the last 75,000 yr. Two longer stratigraphic sections that date back to 175,000 yr B.P. then will be sampled and analyzed using the same techniques to reconstruct the record of the penultimate glacial-interglacial cycle Project goals are to provide direct information on changes in climate and vegetation, to quantify region-wide responses of the pedologic, sedimentologic, and hillslope-geomorphic systems to those changes, to further document a losess-based proxy record of activity of the Cordilleran Ice Sheet, and to test several climate proxy records.