--> ABSTRACT: Regional Strain in U.S. Gulf Coast Using Fry Analysis of Salt Dome Spacing, by Stephen L. Wust; #91022 (1989)

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Regional Strain in U.S. Gulf Coast Using Fry Analysis of Salt Dome Spacing

Stephen L. Wust

Fry plots result in a representation of the strain ellipse for the area studied. Ronnlund and Koyi, in 1988, showed that this technique could be successfully applied using spacing of salt domes. The method is here applied to the United States Gulf Coast using a regional map of salt distribution. Only diapiric salt bodies were considered; salt tongues and massifs (mostly far offshore) have no distinct center points and could not be included.

Axial ratios and directions of long axes for the resultant ellipses were compared for four regions: Mississippi delta onshore and offshore, Atchafalaya basin onshore, Houston salt basin onshore, and offshore shelf. Directions of extension correspond to those derived from orientations of regional normal faults--north-northeast in the delta, northwest along the Texas coast, and mixed northeast and northwest in the central zone. Highest strain (axial ratio 3.86:1) was recorded in the Mississippi delta and Houston regions, with the lowest strain value (1.55:1) from the western offshore shelf. An intermediate axial ratio (2.92:1) was calculated for the Atchafalaya basin.

Center-point spacing analysis of salt dome distribution provides a useful means of calculating regional strain. In the U.S. Gulf Coast, postdiapiric deformation may be attributed to differential sediment loading in a combination of Tertiary depocenters and recent deltaic systems. Extension directions are consistent with regional faulting patterns.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.