Lithostratigraphy and petrology of the Prospect Mountain Quartzite and Pioche Shale, Upper Proterozoic to Middle Cambrian, southern Snake Range, Nevada.

摘要

Prospect Mountain Quartzite and Pioche Shale have been studied and correlated over much of the Eastern Great Basin. Because of the structural complexity in this area, nearly all of these outcrops were incomplete or deformed, especially in the southern Snake Range. A nearly continuous section (1,044 m) from the Precambrian Osceola Argillite to the Middle Cambrian Pole Canyon Limestone was described in detail. The Prospect Mountain is considered to be one formational unit. It was subdivided into two informal members, the lower Stella Lake and upper Pilot Knob based on the differences in lithology, texture, and the identification of a distinctive shale bed in the sequence. Five distinct lithostratigraphic units were defined for each formation based on petrographic descriptions of 172 thin sections. Seven facies and a depositional model were interpreted describing a transgressive sequence from a distal braidplain facies to a back-shoal facies of the middle Cambrian carbonate shoals.