U-Pb Geochronology of the Wildhorse Gneiss Complex, Pioneer Mountains Core Complex, South-Central Idaho

Idaho State University, Pocatello ID

Investigators

Abstract

Faculty and students from Idaho State University are engaged in integrated field, petrographic, geochemical, and geochronologic study of Neoproterozoic strata exposed in the Pioneer Mountains core complex of Idaho. Previous studies of Paleozoic strata have identified an unusual population of detrital zircons with ages of about 750 to 600 Ma. Rocks of this age are very unusual along the western margin of North America. Fieldwork has traced the apparent origin of these rocks to the Pioneer Mountains. This study utilizes student projects to determine the source of these rocks and confirm their isotopic ages. The work has implications for paleogeographic reconstructions of Rodinia and evaluation of the Snowball Earth hypothesis.