Review of Geology of Mississippi Salt Domes Involved in Nuclear Research

Charles T. Swann

Mississippi salt domes were a part of nuclear research activities as early as 1960. Bruinsburg dome, Claiborne County, was initially considered suitable as a site for underground nuclear tests in the Ripple Program. The Bruinsburg dome is a shallow piercement dome with cap rock 1,629 ft below the surface. Additional screening resulted in Tatum dome, Lamar County, being chosen as the test site. Approximately 2,700 ft below the surface, two nuclear devices were detonated, one in 1964 and one in 1966. These detonations are referred to as Project Dribble and Project Sterling respectively, and are part of the Vela Uniform Program sponsored by the U.S. Department of Defense and the former U.S. Atomic Energy Commission. Tatum dome is a shallow piercement dome with cap rock appro imately 900 ft below the surface.

More recent investigations (1974-1987) were initiated to choose a site for the nation's first high-level nuclear waste repository. These investigations, sponsored by the U.S. Department of Energy, identified the Lampton (Marion County), Richton (Perry County), and Cypress Creek or Agnes (Perry County) domes as preferred sites. Lampton dome, a shallow piercement dome with cap rock at 1,305 ft below the surface, was later rejected from the repository siting process. The Cypress Creek dome is a shallow piercement dome with cap rock at a depth of approximately 1,195 ft. The Richton dome, Mississippi's shallowest salt structure, has cap rock as shallow as 497 ft below the surface. Richton and Cypress Creek domes were considered potentially acceptable sites, although all present repository iting activities are focused on the Yucca Mountain site, Nye County, Nevada.

Nuclear research regarding Mississippi salt domes has yielded abundant geologic data and short-term economic benefits. However, timing of research and private utilization plans at Bruinsburg and Richton domes suggest that the research activities have had a detrimental effect on utilization of Mississippi salt resources. This potential conflict of salt dome uses may have influenced private industry to seek other sources of salt supply. Tatum dome, contaminated by highly radioactive isotopes, can never be utilized for any purpose. These factors may contribute to the fact that none of Mississippi's 61 known salt domes are being commercially utilized.

AAPG Search and Discovery Article #91029©1989 AAPG GCAGS and GC Section of SEPM Meeting, October 25-27, 1989, Corpus Christi, Texas.