Tectonic implications of a petrographic and geochemical characterization of the Lower to Middle Jurassic Sailor Canyon Formation, northern Sierra Nevada, California

Abstract

The Lower to Middle Jurassic Sailor Canyon Formation in the northern Sierra Nevada of California consists of basinal volcaniclastic and tuffaceous sedimentary rocks. Petrographic and geochemical data from the formation provide an opportunity to assess a proposed ∼400 km of pre–Late Cretaceous dextral strike- slip displacement on the cryptic Mojave–Snow Lake fault. A corollary to the proposed displacement is that Triassic-Jurassic volcanic complexes exposed in eastern California were the source for Sailor Canyon Formation sediments. However, geochemical data derived from volcanic rocks from this area are unlike those of the volcanic provenance characterized for the Sailor Canyon Formation. Comparisons of geochemical data suggest that contemporaneous volcanic centers exposed in western Nevada north of ∼38°N may be better candidates for the source of the volcanic material in the Sailor Canyon Formation. This interpretation implies that dextral strike-slip displacement on the Mojave–Snow Lake fault may be less than ∼200 km, a value that agrees with some interpretations of Mesozoic intrabatholithic displacements in the Sierra Nevada.