Processes of Late Tertiary-Age Mass Transport and Associated Deposits Along the Eastern Mexico Margin, Southern Gulf of Mexico

Lorena Moscardelli¹, Lesli Wood¹, Ricardo Torres-Vargas², Juan Bermúdez², and G. López-Leyva^3
1Bureau of Economic Geology, Jackson School of Geosciences University of Texas at Austin, Austin, TX
²Instituto Mexicano del Petroleo, Mexico City, Mexico
³PEMEX, Mexico City, Mexico

Significant volumes of mass transport complexes (MTCs) appear to have been shed from the shelf edge of eastern offshore Mexico during the late Tertiary. A large 3D seismic survey was used to map shelf-edge clinoform packages and individual clinoforming units in detail. A significant surface bounding the base of this MTC-rich section that was mapped on the shelf appears to separate a period of aggradational clinoform development from a later period of oversteepened clinoform development. Further detailed mapping shows that clinoform failure is progressive, migrating from north to south with time. Large down-to-the-east normal faults appear to verge westward, marking the initial updip zone of failure. Large cookie-bite features show the volume of material detached from the upper slope to be slope-attached MTCs. However, a significant volume of the material that failed downslope derives directly from the failure of oversteepened clinoforms, suggesting a series of sandy, shelf-attached MTCs in basinward locations. A large canyon can be seen in the south parts of the mapped survey that most likely feeds sediments directly eastward. Semblance images along the basal MTC surface show dense cat’s claw scours and major truncation of older, underlying upper-slope and delta topset, foreset, and toe-set architecture. Some of these “erosional remnants” may provide exploration opportunities. Cretaceous-age, mass transport deposits form the major reservoir in Cantarell field of offshore Mexico, suggesting that additional opportunities may lie in the final resting place of these Tertiary-age, sandy, shelf-attached MTC deposits.

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas