Presidential Young Investigator Award: Desert Geomorpho- logy, Focusing on Dating Techniques and Paleoenvironmental Reconstruction

总统青年调查员进行的研究将集中于发展和应用利用具有时间控制和广泛分布的陆地记录重建环境变化的方法。由首席研究员为岩石清漆涂层开发的新的年代测定和古生代环境方法，将允许对许多以前无法确定年代的沙漠表面进行辐射年龄测定和时间测定。表面涂层的化学变化被发现记录了过去的尘埃水平、碱度和邻近植被的光合作用途径的系统变化。下一阶段的研究包括对湿温带环境下山坡碎屑的研究，以及进一步发展岩石清漆测年方法。了解环境变化依赖于获取可追溯且无处不在的“代理”记录。沙漠清漆和坡面积层沉积物为半干旱和湿润环境下的古环境重建提供了重要信息。

Research conducted by the Presidential Young Investigator will focus on development and application of methods for reconstructing environmental changes, using terrestrial records having both time control and wide distribution. New dating and paleoen>vironmental methods developed by the Principal Investigator for rock varnish coatings, will permit radiometric age assignments and chronometric age-determinations of many previously undateable desert surfaces. Chemical changes in surface coatings have been found to record systematic variations in past levels of dust, alkalinity and photosynthetic pathways of adjacent vegetation. The next phase of research includes study of hillslope debris in humid-temperate environments and further development of rock varnish dating methods. Understanding environmental changes depends on obtaining "proxy" records that are both dateable and ubiquitous. Desert varnish and slope colluvium deposits hold great promise to provide important information for paleoenviromental reconstruction of past events in both semi-arid and humid environments.