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Abstract: A New Model for the Role of Salt in the Salina Basin of Southeast Mexico

Adan Oviedo, Guillermo Mora, Richard Herbert

The Salina basin lies on the southern margin of the Gulf of Mexico, adjacent to the Late Cretaceous-Tertiary foldbelt of the Sierra de Chiapas. As its name implies, the basin contains a significant quantity of salt, which is interpreted to be a laterally equivalent deposit of the Jurassic Louann Salt in the northern Gulf of Mexico. Compressional tectonics, intermittently active since the Late Cretaceous, has profoundly affected the distribution of allochthonous salt in the basin.

Traditional models of the Salina basin interpret the salt tectonics as dominated by steep, vertical-sided salt diapirs. Although the presence of isolated diapirs cannot be ruled out, recent studies of wells and improved-quality seismic data indicate the widespread presence of remnant salt canopies of sheets in the basin. These canopies exhibit many of the characteristics of the same features now identified in the northern Gulf of Mexico. Canopy emplacement was initiated during the Paleocene in response to thrusting and burial under a thick foredeep sediment load, prograding from the south. The widest extent of the salt canopied occurred during the Early Miocene. Subsequent elevation of the Sierra de Chiapas provided a large sediment influx, which loaded the canopies, forming intra-sal basins. Some of these developed into large salt evacuation basins, of which the Comalcalco and Macuspana basins are examples. A number of oil fields have been discovered below the remnant salt sheets, with significant future potential remaining.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France