Lower Cambrian and Upper Precambrian Strata of Beaver Mountains, Utah

Abstract

Cambrian Prospect Mountain Quartzite and seven underlying units, tentatively considered Precambrian, are mapped in the Beaver Mountains. This concordant section begins where alluvium covers the base of the oldest unit and ends at the contact between the Prospect Mountain Quartzite and the overlying Pioche Shale. Assigned to the Precambrian is 5,145 ft of strata. These rocks are slate, argillite, marble, metasiltstone, quartzite, and conglomerate, which have undergone very low-grade regional metamorphism. The uppermost Precambrian unit, a purple conglomeratic quartzite, is correlated with the Mutual Formation of north-central Utah. The overlying tan and pink Prospect Mountain Quartzite is at least 4,000 ft thick. Lithologic correlation of the Beaver Mountains section with the strata described by Christiansen (1952) from the Canyon Range in central Utah is established. Tentative correlations with the late Precambrian McCoy Creek Group of eastern Nevada and western Utah (Misch and Hazzard, 1962) are suggested.