COLLABORATIVE RESEARCH: Global Change: The Geologic and Pedologic Record of Climate and Vegetation in Pleistocene Palouse Loess, Pacific Northwestern U.S.

哥伦比亚高原的帕卢塞黄土中的五个地点，每个地点都跨越最近75,000年（通过当前间冰期的最后一个冰期周期），将绘制暴露图，进行描述和采样。该序列的网站将形成一个生物气候样带约200毫米至700毫米的降水量，温暖到凉爽的温度，灌木草原森林。灰岩年代学、土壤地层学和热释光测年法将提供遗址之间的年代控制和相关性。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关于植物覆盖、植物群落类型和温度随时间的波动的信息。遗址地层学和古土壤的微形态（土壤显微镜）、物理和化学性质将产生对黄土沉积和侵蚀循环、土壤发育以及植被和气候变化与土壤形成过程和景观演变的关系的解释。古土壤和黄土磁化率的测量将作为对中国黄土气候代用模型的重要检验。上述子项目将被综合成一个定量描述模型，描述过去75,000年中5,000到10,000年时间段的变化。两个较长的地层剖面可以追溯到175，000年B. P.，然后将使用相同的技术进行采样和分析，以重建倒数第二次冰期-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，量化整个区域土壤学、沉积学和山坡地貌系统对这些变化的响应，以进一步记录基于损失的科迪勒拉冰盖活动的代理记录，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.