Bureau of Economic Geology, The University of Texas at Austin (www.beg.utexas.edu).
American Association of Petroleum Geologists Annual Meeting, Dallas, April 18-21, 2004
Regional Structural Setting and Evolution of the Northeastern Deep Gulf of Mexico
Renaud Bouroullec, Paul Weimer, and Olivier Serrano
This study presents the results of structural analyses of the Mississippi Canyon and Atwater Valley protraction areas, northeastern deep Gulf of Mexico. Analysis included 19,557 km of 2-D and 378 square miles of 3-D seismic data, tied to 150 exploration wells and biostratigraphy. The study area is an active exploration province, including 50 fields and discoveries.
Structural analyses were carried out to characterize the geometry and kinematics of (1) the basement, (2) the extensional, contractional and strike-slip systems, and (3) the multi-level allochthonous salt systems from Jurassic to present. This study also investigates the intricate temporal and spatial relationship between these three tectonic systems, in relation to the formation of main structural traps.
Basement structures consist of a series of horsts, grabens and half-grabens with various orientations. This organization greatly controls the subsequent evolution of the basin. Three successive extensional and contractional systems are present: (1) a regional pre mid-Oligocene E/W trending system, (2) a regional post mid-Oligocene NNW/SSE trending system migrating landward through time, and (3) series of local NNW/SSE trending Upper Miocene systems. Three levels of allochthonous salt systems are present at the top Albian (99 Ma), top Cretaceous (66 Ma) and during the Neogene (between 10 and 4 Ma). Four main contrasting styles of allochthonous salt systems have been identified: basement, counterregional, Roho, and foldbelt related systems. Some of these systems have been modified by late strike-slip tectonics triggered by differential subsidence along the slope, itself related to the irregular early (autochthonous and early allochthonous) salt distribution.