Geologic and Geophysical Evidence for a Pacific Origin for Seawater Filling the Callovian Gulf of Mexico Evaporite Basin

Abstract

The Gulf of Mexico (GOM) preserves one the largest (1,137,000 km²) and thickest (from hundreds of meters to more than 10 km) deposits of halite and anhydrite on Earth. Two possible origins for this massive deposit, now extensively remobilized by gravity tectonics, include the Jurassic proto-Pacific Ocean to the west of the GOM and the Jurassic proto-Atlantic basin to the east of the GOM. We integrate stratigraphic information for exposed marine rocks of Callovian age in the so-called “Portal de Balsas” area of central Mexico, that forms an approximately 200-km-wide in a north-south direction, and about 750-km-wide east-west-trending corridor. Geological data from The Portal de Balsas corridor includes marine rocks well dated using ammonites (Stephanoceras, Wagnericeras and Reineckeia) by early workers including Imlay (1953), Erben (1956), López Ramos (1981) and Cantú-Chapa (1981). The Balsas corridor crosses middle Mexico, roughly parallel to the Trans Mexican Volcanic Belt, from Michoacán-Guerrero States eastward to the Tampico-Veracruz area. The trend of the corridor exhibits a northwest trend indicating its close relation to Jurassic age, subduction-related backarc basins. In the northeastern GOM, deep-penetration seismic data reveals one of the few seismically-imaged salt-filled rift basins along the northeastern GOM in the US maritime zone. This basin exhibits a salt fill in the NW GOM that diminishes to the SE GOM in the direction of Cuba indicating a western source of Jurassic seawater that we relate to the Callovian Balsas corridor in central Mexico. We propose the Balsas corridor is a Callovian-age, Gibraltar-like marine strait through the highlands of Mexico that connected the Pacific Ocean and GOM and filled the possibly, subsealevel GOM sag basin from west to east.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016