Abstract: Reddell Salt Dome of Louisiana--Geotemperatures and Halokinetics

Madhurendu Bhushan Kumar

The Reddell structure in Evangeline Parish, Louisiana, is a complexly faulted dome on a deep-seated salt plug (salt top at 12,368 ft or 3,770 m). The 10,000-ft (3,048 m) level isotherms reflect the structural configuration of the dome. Wells in the area have encountered high temperatures with geopressure; some of the high-temperature wells are hydropressured and are located on the crestal part of the structure. These pressures are attributed to the deep-seated salt plug functioning as an efficient thermal conduit.

Wells in the area, including Wilcox (lower Eocene) penetrations, provide reasonably adequate control for a study of the interplay between sedimentation and salt movements close to the northern rim of the Gulf Coast salt basin. On the basis of electric-log correlations, a stratigraphic section from the Eocene through the Miocene was divided into 22 intervals.

The isopach maps constructed from these intervals reveal that the centers of uplift shifted with time while the structural growth of the dome progressed in varying degrees. Considering stratigraphic thinning as an approximate measure of salt uplift, the growth rates are estimated at 0.06 mm/year for the Wilcox (lower Eocene), 0.03 mm/year for the Claiborne (middle Eocene), 0.01 mm/year for the Jackson-Vicksburg-Frio (upper Eocene-Oligocene), and 0.02 mm/year for the Miocene. The lateral shifts of depositional "thins" are interpreted in terms of spines of motion active at different rates at different times. The overall patterns of salt movement through the time intervals mapped suggest that initially the salt rose in the south, and, near the end of the Miocene, it rose in the north. Th northward salt movement may be related to the emplacement of Pine Prairie, Eola, and Cheneyville domes, which mark the northernmost edge of the Gulf Coast salt basin.

AAPG Search and Discovery Article #90965©1978 GCAGS and GC Section SEPM, New Orleans, Louisiana