Tectonic implications of a late Mesozoic fold and thrust belt in northwestern Nevada

Abstract

The Luning-Fencemaker fold and thrust belt of northwestern Nevada formed east of the Mesozoic Sierran arc in a back-arc setting where noncontinental crust localized marine deposition and subsequent deformation. The fold-thrust belt was active in Middle or Late Jurassic and Early Cretaceous time and evolved during major northwest-southeast contraction. Comparable shortening was not developed in the Sierran arc, and for much of the Mesozoic the arc and the back-arc regions were at least partially decoupled and separated by the regionally extensive Pine Nut fault system, which underwent substantial left-lateral displacement. Development of the fold-thrust belt and associated strike-slip fault is attributed to oblique subduction. The shortening axis of the fold-thrust belt and inferred displacement of the strike-slip fault are incompatible with right-oblique subduction and call for an interval of left-oblique convergence during part of Jurassic-Cretaceous time.