Oxygen and Hydrogen Isotope Studies of Igneous Rocks and Associated Hydrothermal Alteration

9317036泰勒低18 O热点，如夏威夷可能代表回收的低18 O洋壳。 这一假设将通过与地幔柱有关的火山岩的18 O/16 O绘图进行检验，最初侧重于萨摩亚和瓜达尔卡邦热点链。 目前正在建造一台激光同位素分析仪，可以对非常小的样品进行18 O/16 O分析;它将用于研究含水流体和共存矿物以及火山玻璃的详细18 O/16 O交换行为。 另外两个正在进行的项目将完成：（1）与高加索山脉Chegem Caldera有关的热液效应，俄罗斯 这是世界上侵蚀最深、暴露最好的年轻（2.8 Ma）破火山口;在700 m厚的破火山口填充灰流凝灰岩段中，它包含一个显著的18 O贫化区，其中共存的斑晶和火山玻璃大大超出了18 O/16 O平衡。 (2)不列颠哥伦比亚省变质核杂岩中与断层有关的热液系统。 对世界上一些最大的变质核杂岩的同位素研究将为地壳中主要断裂带的渗透性提供新的见解，并可能帮助我们了解含水流体在地震中的作用。

9317036 Taylor Low-18O hotspots like Hawaii may represent recycled low-18O oceanic crust. This hypothesis will be tested by 18O/16O mapping of volcanic rocks associated with mantle plumes, initially focusing on the Samoa and Guadalupe hotspot chains. A laser fluorination apparatus is being constructed, allowing the analysis of 18O/16O on very small samples; it will be used to study detailed 18O/16O exchange behavior of aqueous fluids and coexisting minerals and volcanic glasses. Two other on-going projects will be completed: (1) Hydrothermal Effects Associated with Chegem Caldera, Caucasus Mtns., Russia. This is the most deeply erode, best exposed, young (2.8 Ma) caldera in the world; it contains a remarkable zone of 18O depletion in a 700 m- thick section of caldera-fill ash-flow tuff, where coexisting phenocrysts and volcanic glass are drastically out of 18O/16O equilibrium. (2) Hydrothermal Systems Associated with Faulting in Metamorphic Core Complexes, British Columbia. This isotopic study of some of the largest metamorphic core complexes in the world will provide new insight into the permeabilities of major fracture zones in the earth's crust, and may help us to understand the role of aqueous fluids in earthquakes.