Geochemical Investigations of Major Environmental and Tectonic Changes in the Permian and Triassic

记录了海水的化学和同位素组成 包含了大量关于气候的信息 海底的地质构造热液活动 关于海平面变化、海洋环流和 大气成分 问题是要解开各种 在这些过程中记录在沉积物中的信号。 这里 我们将研究二叠纪和早期 三叠纪，一个全球环境变化的时期。 我们的研究将 集中在SR和Nd同位素记录，但也将包括 其他各种可能相关的地球化学指标。 通过 合作者，我们已经获得了一套样品这项工作 从地理分布广，地层控制， 重叠部分。 我们的大部分工作将在牙形刺上完成， 其提供地层信息以及具有 方便地高浓度的大多数元素的 感兴趣，以便可以对单个个体进行分析， 碎片在大多数情况下。 我们会仔细调查 成岩作用，并试图更精确地描绘 比以前所做的时间和规模的 观察到海水中Sr和Nd同位素比值的巨大变化 在这段时间里。 数据将根据以下方面进行检查： 古构造、古气候和 古地理学 此外，我们亦会探讨 在这个时间间隔内牙形刺的U-Th测年， 我们同位素研究的时间框架， 段间相关性

The record the chemical and isotopic composition of seawater through time contains a wealth of information about climate, tectonics, hydrothermal activity on the sea floor, and perhaps even about the details of sea level change, ocean circulation and atmospheric composition. The problem is to unravel the various signals recorded in sediments in terms of these processes. Here we will examine the time period spanning the Permian and early Triassic, a time of global environmental change. Our study will concentrate on the SR and Nd isotopic record, but will also include various other, probably related, geochemical indicators. Through collaborators, we have acquired a suite of samples for this work from geographically widespread, stratigraphically controlled, overlapping sections. Much of our work will be done on conodonts, which provide stratigraphic information as well as having conveniently high concentrations of most of the elements of interest, so that analyses can be made on single individuals or fragments in most cases. We will carefully investigate possible diagenetic effects, and attempt to delineate much more precisely than has been done previously the timing and magnitude of the observed large changes in Sr and Nd isotopic ratios in seawater during this time period. The data will be examined in terms of current knowledge of paleotectonics, paleoclimate and paleogeography. In addition, we will explore the feasibility of U-Th dating of conodonts in this time interval, in order to refine the temporal framework for our isotopic studies and to aid in section-to-section correlation.