Middle Jurassic Tectonics and Paleogeography (160 Ma).

Middle to Late Jurassic (160 Ma)

Major arc magmatism

Initial collision between southern Wrangellia and Cordilleran margin at approximately the latitude of Klamaths and Sierras

Fringing arcs south of collision zone

Ophiolites obducted in collision zone and in inter arc region between Cordilleran arc and fringing arcs

Foreland basin in Utah and thrusting in Nevada

Rift basin in southwestern North America related to opening Gulf of Mexico