Petrologic Evolution of the Northern Eldorado Mountains, Southern Nevada

位于内华达州南部、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伸展走廊是研究大陆伸展和岩浆作用之间相互作用的理想天然实验室。大部分100%的伸展集中在一个相当短的时间间隔（1-4 m.y），之后断裂和火山活动都迅速减少。本研究将重点研究内华达州埃尔多拉多山脉北部的构造/构造和岩石学演化，该地区已具备良好的地质填图、高精度的40Ar/39Ar年代学和构造分析数据库。大规模伸展前、伸展中、伸展后喷发的火山岩主要元素地球化学特征的变化，揭示了岩浆岩在伸展过程中对下地壳和地幔流变学变化的响应。研究结果将为研究高伸展陆块的伸展速率与基性岩浆组成变化之间的关系提供直接的文献资料，并对其他伸展构造环境具有广泛的应用价值。

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.