THE “HISPANIC CORRIDOR”, ACROSS THE EARLY GULF OF MEXICO

Triassic-Jurassic sedimentary continental rocks from Huizachal and Huayacocotla anticlinoria, were analysed, since 1988, by palynostratigraphical, geochemical and petrographic methods. Obtained data allow conclude that a Liassic allostratigraphical sequence, deposited in a unique half-graben, bordered by alluvial fans, with anastomosed fluvial system, was invaded by marine incursions from SE, and divided, during Aalenian, in two fragments by SW ward displacements of tectonic blocks.

New petrological, paleontological and paleogeographical results enhanced the southern Tlaxiaco Anticlinorium stratigraphy, showing that its Liassic and Middle Jurassic sequences were deposited also into a similar half-graben connected, toward NW, to the Liassic “Portal del Balsas” epicontinental sea that became the Dogger “Hispanic Corridor”. Finally, the Jurassic sequences outcropping at the three known anticlinoria were correlated successfully and allow know the NE provenance from metamorphic quartzose rocks deposited above La Boca Alloformation, at Huizachal, and above Consuelo Group, at Tlaxiaco anticlinoria, both correlated to Cahuasas Formation at Huayacocotla Anticlinorium. Metamorphic quartz was produced by erosion of a lifting region due to a Late Liassic hot spot (sensu Tuzo Wilson) with triple-junction, appeared at the intersection of Precambrian Texas-Boquillas-Sabinas and Paleozoic Tampico-Lázaro Cárdenas megashears, at the present central Gulf of Mexico; cratonic quartzose sediments were transported by fluvial systems toward W and SW. An initial RRR triple junction system was formed, composed by SE-NW Texas-Boquillas-Sabinas, SW-NE Campeche Escarpement and N-S Nautla-Pico de Orizaba arms, bordering the Texas-Louisiana, Western Region of Mexico, and Chiapas-Yucatán subplates. Because the last subplate was still joined to South American plate during Jurassic, only Texas-Louisiana and Western Region of Mexico subplates displaced NW ward, because Texas-Boquillas-Sabinas and Vancouver-Bahamas megashears reactivated and a subduction zone existed at Pacific border of North-American Plate. This motion allowed Campeche Escarpement and Nautla-Pico de Orizaba arms became wider ridges and seafloor spreading zones, where the “Hispanic Corridor” formed across the Early Gulf of Mexico.