Wawrzyniec, Tim F.1
(1) The University of New Mexico, Albuquerque, NM
ABSTRACT: Shale, Salt, and Gravitational Sliding – a Threesome of Intrabasinal Tectonic Accommodation Processes with Examples from the Western Gulf Of Mexico
Sediment accommodation within a basin that is enhanced by intrabasinal extension, deformation is often dynamically and kinematically linked to three end-member processes. These processes are not mutually exclusive and include extension related to shale migration, salt diapirism, or coupled to distal, gravity-slide, compressional fold belts. Although the first two processes are issues of rheology, they are different in that the rheology of a body of salt is constant over time, while shale rheology is dependant on a potentially variable fluid content. Therefore, depending on basin geology, all three of these end-member classes may permit extensional accommodation as a function of the dynamic feedback between global tectonic forces, climate, on-going deformation, and the distribution of load forces created by spatial variation in sedimentation rates within and around a basin. The western Gulf of Mexico (GOM) provides examples of this organizational scheme as it spans three underlying structural domains that were first defined during the opening of the GOM. These are the extended continental crust of the northern and southern GOM and their related salt provinces; and the diapir barren, strike-slip transform margin below the Laguna Madre-Tuxpan shelf. This variation provides an excellent setting to contrast the styles of basin accommodation associated with the salt and shale movement (Burgos Basin), gravity-slide/compressional fold belt (Laguna Madre-Tuxpan shelf – Mexican Ridges fold belt), and a largely evacuated shale basin (Macuspana basin). Moreover, it provides a basis for a comparative analysis between the end-member extensional accommodation processes and their unique impacts on their related hydrocarbon systems.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.