Radiogenic Isotopic Study of Diagenesis and Low-grade Metamorphism Pelites

沉积和浅变质泥质岩记录了与地壳流体相互作用的产状、时间和大小，但由于关键矿物，特别是粘土矿物来源的不均质性，这类岩石和事件的放射性同位素研究导致结果不明确。该项目将把放射性同位素研究(Rb-Sr和K-Ar)与扫描电子显微镜(STEM)的详细表征结合起来，以便为解释同位素数据提供坚实的基础。该建议是基于一个成功的“试点项目”开发的墨西哥湾沿岸页岩的Rb-Sr分析方法，该方法证实了构造诱导的流体流动的“幕式”成岩作用。这项研究将通过对墨西哥湾沿岸页岩的进一步研究，以及对纽约北部和威尔士从晚成岩到绿片岩相变质作用的连续层序的分析，将研究范围扩大到成岩作用-低级变质作用的全范围。

Sedimentary and low-grade metamorphic pelitic rocks record the occurrence, timing and magnitude of interaction with crustal fluids, but radiogenic isotopic studies of such rocks and events lead to ambiguous results due to heterogeneity of source of the key minerals, especially clay minerals. The project will combine radiogenic isotopic studies (Rb-Sr and K-Ar) with detailed characterization by scanning transmission electron microscopy (STEM) in order to provide a firm basis of interpretation of the isotopic data. The proposal is based on a successful "pilot project" development of methods for Rb-Sr analysis of Gulf Coast shales that have verified "episodic" diagenesis by tectonically- induced fluid flow. This research will expand the studies to the full range of diagenesis - low-grade metamorphism with further studies of Gulf Coast shales, and analyses of continuous sequences across northern New York and in Wales that span the range from late diagenesis to greenschist facies metamorphism.