Applications of Radiogenic Isotope Geochemistry to Studies of Igneous and Hydrothermal Processes

这是为了继续支持三个独立的计划， 放射性成因同位素地球化学研究 热液作用、岩浆系统和地幔 地球化学 1.热液过程的研究将 强调进一步发展用于确定 流体运动的时间和尺度。 这些技术可以包括 流体包裹体定年，硫化物定年， 碳酸盐、磷酸盐及副矿物增生，稀土元素 分析各种热液相，包括硫化物和 萤石。 研究将集中在密西西比河谷类型 (MVT)美国的矿床和与深成矿作用有关的矿床， 英国 2.对岩浆系统的研究将集中在 利用Rb-Sr技术研究岩浆分异作用， 岩浆房居住区的分异时代 喷发年龄，以及火山喷发过程中物质传递的研究 系统. 美国和其他地方的一些系统已经被 选择学习。 3.地球化学研究现状 喀麦隆线下的地幔将被扩大以研究痕迹 元素富集过程与岩石圈年龄的关系 使用来自各种火山岩的熔岩和/或超镁铁质捕虏体 中心. 此外，还介绍了利用 40 Ar-39 Ar正在研制中。

This is for continued support of three separate programs of research in radiogenic isotope geochemistry as applied to hydrothermal processes, silicic magma systems and mantle geochemistry. 1. The research in hydrothermal processes will emphasize the further development of techniques for determining the timing and scales of fluid movement. These techniques may include dating of fluid inclusions, dating of sulfides, dating of carbonates, phosphates and accessory mineral overgrowths, and REE analysis of a variety of hydrothermal phases including sulfides and fluorite. Research will be concentrated on MIssissippi Valley Type (MVT) deposits and pluton-related mineralization in the U.S. and U.K. 2. Studies of silicic magma systems will focus on dating of magma differentiation using Rb-Sr techniques, the longevity of magma chamber residence by resolving differentiation ages from eruption ages, and the study of mass transfer within silicic systems. A number of systems in the U.S. and elsewhere have been chosen for study. 3. Current research on the geochemistry of the mantle under the Cameroon line is to be expanded to study trace element enrichment processes as a function of lithospheric age using lavas and/or ultramafic xenoliths from various volcanic centers. In addition, techniques for dating young MORB using 40Ar-39Ar are being developed.