REU: Miocene to Recent Sedimentary Conditions on the Peruvian Margin: Apatite Formation, Fluid Circulation, and Diagenesis

在秘鲁外海有三种主要的磷块岩：（1） 易碎的浅色纹层，包括小的盾状体， 结核，（2）以泥质为主的磷质砂，（3） 一般颜色较深，岩石化较好，致密的结核和坚硬的地面。 在大洋钻探项目（ODP）第112航次期间回收的岩心 包含所有三种磷块岩类型，并允许膨胀 关于新生代的许多方面的现有信息， 这一地区的第四纪沉积物。 因此，主要 该项目的目的是（1）提高对 海洋学和沉积学因素， 地质记录中磷块岩的幕式沉积， (2)制定地球化学和同位素标准， 区分原始属性中的主要属性 沉积环境，从修改的属性，这些 通过地下盐水的影响或在 后期埋藏成岩作用或改造富集作用 通过沉积过程。 %%% 大陆边缘的磷块岩是一个有趣的， 潜在经济存款。 本研究将探讨 成矿的控制因素。 秘鲁边缘的岩芯沉积物 通过各种地球化学技术的研究， 气候对形成的影响，以及后 流体流动和成岩作用的沉积效应。

Three major types of phosphorites occur off Peru: (1) friable light-colored laminae, including small peloids and nodules, (2) phosphatic sands dominated by peloids, and (3) generally darker, well lithified dense nodules and hard-grounds. The cores recovered during Ocean Drilling Project (ODP) Leg 112 contain all three phosphorite types and allow expansion of the existing information on many aspects of the older Cenozoic to Quaternary sediments of this region. Accordingly, the primary aims of this project are to (1) improve the understanding of oceanographic and sedimentologic factors which control the episodic deposition of phosphorites in the geologic record, and (2) to develop geochemical and isotopic criteria which may distinguish primary properites derived in the original depositional environment, from modified properties, those acquired by the influence of a subsurface saline brine or during later burial diagenesis, or by reworking and concentration through sedimentologic processes. %%% Phosphorites on continental margins are an interesting and potentially economical mineral deposit. This study will examine the controlling factors for the formation of these deposits. Sediments from drill cores on the Peruvian margin will be examined by a variety of geochemical techniques for clues to the climatic influences on formation as well as the post- depositional effects of fluid flow and diagenesis.