ABSTRACT
During the Precambrian and Paleozoic, Mexican terranes were either part of or proximal to Laurentia and Middle America (basements of Mesozoic Maya, Oaxaquia, and Chortis terranes that bordered Amazonia). Obduction of the Sierra Madre proximal terrane in the Late Ordovician was followed by Permo-Carboniferous amalgamation of all proximal terranes into Pangea. Middle Jurassic breakup of Pangea resulted in two continental terranes, Maya and Chortis, which were surrounded by small ocean-basin/arc terranes: Gulf of México, Caribbean Sea, Juarez, Motagua terranes, and the Guerrero composite terrane. All of these terranes were obducted onto North America during the Late Cretaceous–Early Cenozoic, Laramide orogeny. Neogene propagation of the East Pacific Rise into the North American margin has led to separation and northwest translation of the Baja California terrane.
