Salt Tectonism in the Destin Dome Region, Northeastern Gulf of Mexico

MACRAE, GRANT, Texas A&M University, College Station, TX

The continental margin of the northeastern Gulf of Mexico consists of a thick sequence of Mesozoic and Cenozoic sediments that have accumulated almost continuously since the Middle Jurassic in a relatively stable, slowly subsiding, tectonic environment. The distribution of Middle Jurassic (Callovian-age?) salt is widespread with an estimated minimum accumulation thickness of 760 m. Salt movement and associated listric normal growth faulting are the most significant tectonic elements affecting the structural development of the overlying sediments.

Structural and stratigraphic relationships indicated by seismic reflection data suggest two phases of salt tectonism in the Destin dome region. The earliest record of movement of Middle Jurassic salt is in the Oxfordian-age Smackover interval sediments on the Mississippi-Alabama shelf. The development of expanded Smackover interval sedimentary sections is directly related to the regional basinward dip of the presalt surface and to the growth of salt pillows, or rollers, in response to sediment loading. Syndepositional listric normal growth faults occur on the seaward flanks of these salt structures. Growth of the Destin dome anticline on the Florida shelf reflects a significant late phase of salt movement from Late Cretaceous through early Cenozoic time. Differential sediment loading y thick Lower Cretaceous sediments, along with subsequent movement of salt updip onto the Florida shelf, is the interpreted mechanism for growth of the Destin dome anticline. The presalt basement surface appears to be a common detachment surface, or decollement, for salt movement.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)