Abstract: Interaction Between Sedimentation and Salt Tectonics; a Case Study from the Northern Green Canyon and Central Ewing Bank Areas, Northern Gulf of Mexico

VARNAI, PETER
Exxon Exploration Company, Houston, TX;
PAUL WEIMER
University of Colorado, Boulder, CO 80309-0399

The Northern Green Canyon and central Ewing Bank: protraction areas are characterized by complex syndepositional salt deformation and growth-faulting that affect the Pliocene and Pleistocene turbidite sediments. Analysis of a series of isopach maps revealed characteristic thickness variations within the ten studied sequences. The localized depositional thicks consist of divergent seismic facies. The thicks are interpreted as the result of syndepositional salt withdrawal and growth faulting. There are great variations in the position, areal extent and the number of the depositional thicks. The systematic analysis of these depositional thicks showed how salt withdrawal and growth faulting affected the deposition of the different turbidite elements. Salt tectonics had the most important influence on the distribution of basinfloor fans. The thickest and largest fans are interpreted in the southeastern part of the area in the 5.5 - 3.0 Ma interval, where salt withdrawal was most active. Basin-floor fan deposition gradually shifted to the north, following the northward shift in the area of maximum salt withdrawal. No large basin-floor fans were deposited elsewhere, even though extensional growth faulting created large mini-basins in the northern part of the area. This type of extension probably did not create a significant decrease in slope gradient for the coarse grained fraction in turbidity currents to be deposited.

AAPG Search and Discovery Article #90932©1998 GCAGS/GCS-SEPM Meeting, Corpus Christi, Texas