Miocene faulting in the southwestern Sierra Madre Occidental, Nayarit, Mexico: kinematics and segmentation during the initial rifting of the southern Gulf of California

Crustal stretching affecting western Mexico during the Neogene, and its relationship with the opening of the Gulf of California, has been widely studied and discussed for several decades. Nevertheless, the timing and kinematics of the opening is a matter of debate. Most authors essentially agree in considering the rupture of the lithosphere around the Gulf of California, as a fast process that began at similar to 12.5 Ma and became successful in the early Pliocene, when new oceanic crust began to form in the southern Gulf of California. However, recent studies demonstrated that the crustal stretching processes leading to the Gulf opening began in Late Oligocene as a wide rift, which subsequently focused into the present Gulf area in the early Miocene, accompanied by a slight change in the direction of extension. Eventually, after subduction ceased, highly oblique transtensional deformation broke the previously extended lithosphere.