Petrologic and Isotopic Investigations of Chemically Reactive Fluid Flow During Metamorphism

提出的研究将解决变质过程中化学过程的基本问题：(1)反应变质流体通道化的尺度、几何和构造控制是什么？(2)通过扩散和弥散将多少质量输送进或运出流动通道？(3)流动输送的主要元素质量的数量和规模是多少？(4)变质流体流动的年代如何确定？这些问题将通过对加州、意大利和苏格兰三个接触变质地体中碳酸盐岩的新野外研究以及手头的来自新英格兰的三个岩石样品套的实验室研究来解决。流体流动的通道将根据矿物反应产物的分布在野外进行绘制，并与构造特征相关联。通过输运理论对反应过程和氧同位素数据进行定量解释，对传质的几何结构和传质机理进行评价。硅迁移的数量和规模将通过岩石的化学分析进行评估。流体事件的年龄将通过确定独居石和尿晶石形成的变质条件和用质谱仪测量矿物的Ph-Th-U年龄来确定。

9805346FerryProposed research will address fundamental questions about chemical process during metamorphism: (1) What is the scale, geometry, and structural control on the channelization of reactive metamorphic fluid flow? (2) How much mass is transported into or out of the flow channels by diffusion and dispersion? (3) What is the amount and scale of major element mass transport by flow? (4) How can episodes of metamorphic fluid flow be dated? The questions will be addressed by new field studies of carbonate rocks in 3 contact metamorphic terrains in California, Italy, and Scotland as well as by laboratory study of 3 rock sample suites from New England at hand. Channels for fluid flow will be mapped in the field from the distribution of mineral reaction products and correlated with structural features. The geometry amd mechanisms of mass transfer will be evaluated by quantitatively interpreting reaction progress and O-isotope data with transport theory. The amount and scale of Si-transport will be assessed from chemical analyses of rocks. The age of flow events will be determined by defining the metamorphic conditions at which monazite and allanite form and measurement of the minerals' Pb-Th-U ages by mass spectrometry.