Date

3-2010

Degree Name

BS in Earth Sciences

Department

Earth and Soil Sciences Department

Advisor(s)

Scott Johnston

Abstract

Detrital zircon studies of miogeoclinal sediments can help provide a deeper look into the mechanisms leading to continental breakup by studying the evolution of the continental margin of North America. Few detrital zircon studies have been conducted to support previous research and theories about the sedimentation of the Miogeocline from the Neoproterozoic to the Cambrian. Studies targeted at the Basin and Range province of the western United States show a trend of increasing local sediment sources. We analyzed detrital zircons from the Pilot and Deep Creek Ranges in Nevada and Utah via LA-MC-ICP-MS at the University of Arizona LaserChron Center with the hope of better understanding miogeoclinal provenance patterns and deformation during the early history of the North American continental margin. Our results indicate age peaks at 1.0–1.2 Ga, ~1.4 Ga, with increasing 1.6–1.8 Ga grains in the McCoy Creek Group. The Prospect Mountain Quartzite contains mainly 1.6–1.8 Ga zircons in the Pilot Range, and mainly 1.44 Ga and 1.72 Ga zircons in the Deep Creek Range. The Busby Group in the Deep Creek Range is dominated by 1.6–1.8 Ga zircons. Zircons from the McCoy Creek Group are consistent with distal sediment sources from the eastern margin of North America, including Grenvillian and Granite-Rhyolite terranes. Zircons from the Prospect Mountain Quartzite and the Busby Group are derived from more local terranes, including the Mojave, Mazatzal, and Yavapi. Although there are many possibilities to explain the change in sedimentary sources, we favor on the emergence of the Tooele-Uinta Arch and shallow marine transgressions. The Tooele-Uinta Arch may have created a point source for local deposition to the Deep Creek and Pilot Ranges. Shallow marine transgressions to the inner North American continent may have blocked sediment from the east coast from reaching the miogeocline.

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