The Geochemistry of Hydrothermal Sediments, Middle Valley Juan de Fuca Ridge

Rigsby 9400751在这个项目中，PIS将确定在ODP139航段从日本国防军北部中谷回收的碳酸盐的氧、碳、锶和铅同位素组成。他们还将进行全岩心X光照相，以确定井下的纹理变化。其目的是获得过去和现在的热液系统的过去和现在的热剖面、流体平流和沉积物中的金属来源。他们还希望调查这些沉积物中的硫化物矿床。PI和他们的合作者的最终目标是开发热液流体循环以及流体和沉积物之间随时间进行的化学交换的模型。现在正计划(与美国地质勘探局的合作者)对中谷沉积物进行钻探，以专门研究硫化物矿化问题。

Rigsby 9400751 In this project the PIs will determine the O, C, Sr, and Pb-isotopic composition of carbonates recovered from the Middle Valley of the northern JdF at ODP Leg 139. They will also perform whole-core radiography to determine textural variations downhole. The objective is to obtain past and existing thermal profiles, fluid advection, and sources of metals in sediments of past and present hydrothermal system. They also wish to investigate the sulfide ore deposition in these sediments. The PIs' and their collaborators' ultimate goal is to develop models of hydrothermal fluid circulation and chemical exchange between fluids and sediments through time. A second Leg is now being planned (along with USGS collaborators) to drill the Middle Valley sediments to specifically examine the problem of sulfide mineralization.