Metamorphic and Isotopic Studies of Mylonite

糜棱岩的变质和同位素研究

• 批准号: 8707388
• 负责人: Akhaury Sinha
• 金额: $ 10万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: GAA
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 1989-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8707388&HistoricalAwards=false
• 关键词: Metamorphic; Isotopic; Studies; Mylonite

Mylonites form from rock flour ground up along faults. The rocks have received a good deal of study but progress has been difficult because of their fine, almost impalpable grain size. There is considerable current interest in mylonites not only because they may yield information on earthquake mechanisms but also because old faults may act as deep conduits for the flow of metamorphic and hydrothermal fluids. The proposed research includes: (1) determination of the sizes of domains over which chemical and isotopic equilibrium is achieved in mylonites; (2) measurement of reaction progress and chemical metasomatism to estimate fluid-rock ratios; and (3) adapting Rb-Sr and U-Pb isotopic methods to dating mylonitization. These methodologies will be applied to mylonites from the Brevard fault zone, Georgia, the Hope Valley sheartone, Connecticut, and the Borrega Springs mylonite zone, California. The comparison of detailed studies of mylonites from a variety of P-T fluid environments should make it possible to isolate important factors controlling the development of mylonites.

糜棱岩是由沿着断层磨碎的岩石粉形成的。 岩石已经得到了大量的研究，但进展 因为它们的纹理很细，几乎摸不着 尺寸 目前对糜棱岩的兴趣很大， 只是因为它们可以提供地震机制的信息 也是因为古老的断层可能充当了 变质和热液的流动。 拟议 研究内容包括：（1）确定畴的大小 化学和同位素的平衡， 糜棱岩;（2）反应进程和化学成分的测定 交代作用，以估计流体-岩石比率;和（3）适应 Rb-Sr和U-Pb同位素方法测定糜棱岩年龄 这些方法将适用于糜棱岩从 布雷瓦德断层带，格鲁吉亚，希望谷剪切带， 康涅狄格州和加州的博雷加斯普林斯糜棱岩带。 不同类型糜棱岩详细研究的比较 的P-T流体环境应该可以隔离 是控制糜棱岩发育的重要因素。