Abstract

Paleozoic rocks ranging from Cambrian to Pennsylvanian age crop out in the southern Fairview and northern Bristol Ranges. Although complexly faulted, the sequence is essentially complete and may be related to formational concepts widely recognized in the eastern Great Basin. Strata assigned to the Tank Hill Limestone are referable to the Pogonip Group. Rocks assigned to the Silverhorn Dolomite are referable to the Sevy, Simonson and Guilmette Formations. Rocks assigned to the Peers Spring Formation include all formations of the White Pine Group and rocks assigned to the Bristol Pass Limestone may be referred to the Joana Limestone.

Paleozoic rocks in the area are overlapped by early Tertiary volcanic rocks and are surrounded and overlapped by at least two alluvial deposits.

Extensive normal faulting in the area is for the most part older than the volcanic sequence, but younger normal faults, including a range front fault bounding the west side of the Bristol Range cut the volcanic material. A set of west northwest trending high angle faults serves to truncate the northern end of the Bristol Range, dividing the area into two distinctly different structural blocks.

The Bristol Range overthrust allochton in the northwestern part of the Bristol Range is composed of highly brecciated Ordovician through Devonian sedimentary rocks. This feature appears to be a gravity phenomenon and may or may not be related to post-Oligocene monolithologic breccias in the West Range.