The petrography and petrology of a portion of the northern Cedar Mountains, Mineral County, Nevada

Abstract

A combined field and petrographic study describes the spatial mineralogical and textural characteristics of the Cedar Pass pluton and related volcanic rocks. Correlation between mantled feldspars, basic inclusions and geochemistry is made in order to determine the petrologic development of these igneous rocks. The study area is 30 kilometers northeast of Mina, Mineral County, Nevada in the northern Cedar Mountains. Well exposed sub-volcanic rocks have intruded into late Triassic marine sediments. Three periods of structural deformation have been imprinted on these rocks. These plutonic rocks are related to a period of extrusive eruptions which started about 28 million years ago and culminated about 10 million years ago. A minor phase of the pluton has been dated by K-Ar at 24.2 million years. Myrmekite, mantled feldspars and plagioclase morphology have been used to determine the igneous history during Oligocene-Miocene time.