Petrologic Evolution of the Northern Eldorado Mountains, Southern Nevada

内华达州南部埃尔多拉多山脉北部的岩石演化

• 批准号: 9506687
• 负责人: Phillip Gans
• 金额: $ 2.01万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-01 至 1998-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9506687&HistoricalAwards=false
• 关键词: Petrologic; Evolution; Northern; Eldorado; Mountains

The lower Colorado River extensional corridor in southern Nevada, western Arizona and southeastern California is an ideal natural laboratory in which to examine the interplay between continental extension and magmatism. Most of the 100% extension was concentrated over a rather short time interval (1-4 m.y.) after which both faulting and volcanism decreased rapidly. This study will focus on the structural/tectonic and petrological evolution of the northern Eldorado Mountains in Nevada, where a good data base of geological mapping, high precision 40Ar/39Ar geochronology and structural analysis already exists. Changes in major element geochemistry in the volcanic rocks erupted before, during and after large-scale extension will show how the magmatic rocks responded to rheological changes in the lower crust and mantle during extension. The results of this study will provide direct documentation of the relationship between rates of extension and changes in the composition of mafic magmas in highly extended continental terranes, and will have wide-reaching application to other extensional tectonic environments.

内华达州南部，亚利桑那州西部和加利福尼亚州东南部的科罗拉多河下游走廊是一个理想的天然实验室，可以在其中检查大陆延伸与岩浆作用之间的相互作用。 100％延伸中的大多数集中在相当短的时间间隔（1-4 M.Y.）中，因此断层和火山症都迅速下降。这项研究将重点关注内华达州北部Eldorado山脉的结构/构造和岩石学演化，那里的地质映射的良好数据库，高精度40AR/39AR的年代生产学和结构分析已经存在。在大规模延伸之前，之中和之后爆发的火山岩中主要元素地球化学的变化将表明岩浆岩石在延伸过程中如何响应下地壳和地幔的流变学变化。这项研究的结果将直接证明扩展率与高度扩展大陆台上镁铁质岩浆组成的变化之间的关系，并将在其他扩展的构造环境中广泛应用。