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中的五个地点，每个地点都跨越过去 75,000 年（当前间冰期的最后一个冰河周期），将进行曝光绘制、描述和采样。 地点序列将形成降水量约 200 毫米至 700 毫米、温度从温暖到凉爽、从灌木草原到森林的生物气候样线。 地热年代学、土壤地层学和热释光测年将提供年代控制和地点之间的关联。 蛋白石植硅体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产生有关植物覆盖、植物群落类型和温度随时间变化的信息。 场地地层学和古土壤的微形态（土壤显微镜）、物理和化学特性将解释黄土的加积和侵蚀循环、土壤发育以及植被和气候变化与土壤形成过程和景观演化的关系。 古土壤和黄土磁化率的测量将作为对中国黄土开发的气候代理模型的关键测试。 上述子项目将综合成过去 75,000 年 5,000 至 10,000 年时间片变化的定量描述模型。 两个较长的地层剖面可以追溯到距今 175,000 年。然后将使用相同的技术进行采样和分析，以重建倒数第二个冰期-间冰期循环的记录。项目目标是提供有关气候和植被变化的直接信息，量化土壤学、沉积学和山坡地貌系统对这些变化的全区域响应，进一步记录科迪勒拉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.