A major provenance change in sandstones from the Tezoatlán basin, southern Mexico, controlled by Jurassic, sinistral normal motion along the Salado River fault: Implications for the reconstruction of Pangea

Abstract

During the last decades, authors dealing with the reconstruction of Pangea recognized that restoration of Gondwana to its early Mesozoic position relative to Laurentia produces a continental overlap encompassing most of the Mexican territory. To avoid such a continental misfit, some authors suggested that, during early Mesozoic time, southern and central Mexico were originally located farther to the NW of its present position, and that they were emplaced to its current location by lithospheric-scale, NW-trending, sinistral faults during Jurassic time. However, there are currently few reports of NW-trending sinistral faults that were active in Mexico during Jurassic time.In this work, we present sedimentological and petrological data that document a major provenance change within the Jurassic stratigraphic record exposed in the Tezoatlán basin, southern Mexico. We interpret this provenance change as the result of exhumation of Paleozoic metamorphic rocks of the Acatlán Complex along the Salado River fault, which is a WNW-trending sinistral normal fault that bounds the Tezoatlán basin to the north. Our U-Pb detrital zircon ages integrated with previous biostratigraphic data bracket the age of the Salado River fault between ∼179 and ∼170 Ma. Therefore, we reaffirm that sinistral normal block motion along WNW-trending faults took place in southern Mexico during Jurassic time as predicted by some previous geodynamic reconstructions of Pangea breakup.