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“near Surface Contraction, Salt Tectonics and Deep Water Sedimentation, Southern Gulf of Mexico”

Mora-Oropeza, Guillermo 1
1 Subdirección Técnica de Exploración, Pemex Exploración y Producción, Villahermosa, Mexico.

The following study focus on near surface interpretation by using a large offshore 3D seismic survey. The regional framework includes the Chiapas and Juarez Fold Belt, as sediment suppliers, these have been carried out to the shoreline trough the Coatzacoalcos, Grijalva and Cosamaloapan fluvial systems, the sediment composition is derived from granite, metamorphic, siliciclastic and carbonate rocks. Tree major geologic features converge in the area, the East Margin of Mexican Ridges (EMMR), the West Margin of the Salina Basin (WMSB) and the Prograding Shef (PS).

The Shelf in front of (EMMR) is building out to the slope by well defined cycles of progradation; in contrast, the shelf break against (WMSB) is controlled by salt withdrawal and counter regional faulting. Linear amplitude anomalies parallel to the cost suggest shelf sand bars.

The (EMMR) behaves like an embayment in the slope with high amplitude low relief folds, in the West boundary low amplitude high relief detachment folds, and vertical salt diapirs to the East. Sedimentation pinches out en both edges. Seismic amplitude anomalies can be interpreted as huge amount of sand deposited along the topographic low of the embayment and subtle sediment control by the folds.

The (WMSB) shows vertical oval diapirs NNE oriented rising close to the surface with different stages of growing by downbuilding and compression; deeper salt bodies can be interpreted as extension fall and sedimentation. Sea bottom seismic amplitude shows correlation between relative high topographic reliefs, sinuous channel system and underlying extension salt bodies, by other hand topographic lows and lobular shapes is associated to minibasins filling.

 

AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009