Presidential Young Investigator: Desert Geomorphology, Focusing on Dating Techniques and Paleoenvironmental Reconstruction

总统青年调查员开展的研究将侧重于开发和应用重建环境变化的方法，使用既有时间控制又有广泛分布的陆地记录。由首席研究人员为岩石清漆涂层开发的新的测年和古环境方法，将允许对许多以前无法确定日期的沙漠表面进行辐射年龄分配和计时年龄测定。表面涂层中的化学变化被发现记录了过去灰尘、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研究湿温带环境中的山坡碎屑，以及进一步开发岩石清漆测年方法。理解环境变化依赖于获得既可确定日期又无处不在的“代理”记录。沙漠清漆和斜坡堆积物为半干旱和湿润环境中过去事件的古环境重建提供了重要的信息。

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 paleoenvironmental 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 paleoenvironmental reconstruction of past events in both semi-arid and humid environments.