Basin and range extensional tectonics has been the focus of considerable geological and geophysical investigation, however, there are several major problems remaining such as the relation- ship between extension and magmatism and the rate of extension. This study will involve 40 Ar/39 Ar dating of synextensional volcanic rocks and metamorphic rocks from east-central and western Nevada and western Arizona. Results will address the question of strain rates and whether extension was synchronous or diachronous across domains and if magmatism was concurrent with extension.
