The Lateral Extent and Tectonic Significance of Late Miocene/Pliocene Inverted Metamorphism in the Himalaya

喜马拉雅山晚中新世/上新世反转变质作用的横向范围及其构造意义

• 批准号: 9614869
• 负责人: Timothy Harrison
• 金额: $ 25.04万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-01-01 至 2000-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9614869&HistoricalAwards=false
• 关键词: Lateral; Extent; Tectonic; Significance; Late

9614869 Harrison Under normal circumstances, heat and pressure increase with depth in the earth's crust, however a number of cases of inverted metamorphic gradients are well documented in zones of tectonic deformation. This study involves the collection of data that will allow the testing of two competing hypotheses of "up-side-down" metamorphic sequences. One hypothesis holds that warmer rocks are thrust over cooler rocks which became heated from above, - producing an inverted thermal metamorphic sequence. The second hypothesis proposes that previously metamorphosed rocks, once cooled, are thrust over other previously metamorphosed but lower grade rocks. This leads to an up-side down gradient in the grade of ancient metamorphic conditions but does not reflect an instantaneous up-side-down temperature gradient. Results will be important in understanding the tectonic significance of many examples of inverse metamorphism.

9614869哈里森在正常情况下，热和压力随着地壳深度的增加而增加，然而，在构造变形带中有许多反转变质梯度的例子。这项研究涉及的数据收集将允许测试两个相互竞争的“倒置”变质序列假说。一种假说认为，较热的岩石被推到较冷的岩石上，这些较冷的岩石从上方加热，从而产生倒置的热变质序列。第二种假设认为，先前变质的岩石一旦冷却，就会被推到其他先前变质但级别较低的岩石之上。这导致了古变质条件等级的倒置梯度，但并不反映瞬时的倒置温度梯度。这一结果将对理解许多逆变质作用的构造意义很重要。