Regional Structural Setting and Evolution of the Northeastern Deep Gulf of Mexico
Renaud Bouroullec, Paul Weimer, and Olivier Serrano
Department of Geological Sciences, University of Colorado, Boulder, Colorado
This Mississippi Canyon and Atwater Valley protraction areas of the northeastern deep Gulf of Mexico comprise an active exploration province that includes 50 fields and discoveries. The results of structural analyses of the area include 19,557 kilometers of 2 dimensional and 378 square miles of 3 dimensional seismic data that have been tied to 150 exploration wells and related biostratigraphy.
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, east-west trending system, (2) a regional post mid-Oligocene, north-northwest trending system migrating landward through time, and (3) a series of local, Upper Miocene, north-northwest trending systems. Three levels of allochthonous salt systems are present at the upper Albian 99 Ma, upper Cretaceous 66 Ma and within the Neogene between 10 and 4 Ma. Four principal 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 a slope that is related to the irregular early salt distribution of autochthonous and early allochthonous origin.
AAPG Search and Discovery Article #90032©2004 GCAGS 54th Annual Convention, San Antonio, Texas, October 10-12, 2004