Chronology of the structural and petrologic development of the southwest Sierra Nevada foothills, California: Summary

Abstract

Metamorphic country rocks of the southwest Sierra Nevada foothills represent the southernmost exposures of the western foothills metamorphic belt. The rocks of the foothills belt in this region are disrupted and metamorphosed by the Cretaceous batholith to a much greater extent than to the north, probably owing to a deeper level of exposure. The oldest country rocks in the region consist of the Carboniferous to Triassic Kings—Kaweah ophiolite belt which served as basement for Jurassic volcanic arc and continent-derived clastic sequences (Saleeby, 1978, 1979). The history of ophiolite generation, sea-floor transport, continental margin accretion, and volcano-plutonic arc growth is recorded by numerous petrogenetic and deformational episodes. Useful time constraints have been derived for a significant number of these episodes by U/Pb and K/Ar geochronometry. These time constraints have facilitated the construction of an absolute chronology for the structural and petrologic evolution of the region. In this paper, the critical geological and geochronological relations are summarized. The isotopic data and their interpretation, and the detailed field relations of the rocks dated along with supporting petrographic and petrochemical data are presented in the complete article in Part II.

Additional details