One of the remaining fundamental questions in extensional tectonics is the role of intrusive rocks which commonly are emplaced during extension. The Miocene intrusive complex of the Eldorado Mountains of southern Nevada was emplaced broadly synchronously with extreme crustal extension. It provides a unique opportunity to investigate the nature and genesis of granitic and more mafic magmas in extensional settings and the interplay between tectonism and igneous processes. This project will employ field, geochronologic, petrographic and barometric data to assess the role of the plutonic rocks in the tectonic and volcanic history of this region. Results should apply to the general questions of the relationship between pluton emplacement and extensional deformation, the chemical and mechanical effects of plutonism on the upper crust and the origin of petrochemical "fingerprints" of extensional igneous rocks.
