Abstract: Fossil Salt Structures in Vacherie Salt Dome Area, Louisiana

C. T. Crowe

Subsurface structural studies around Vacherie salt dome, northwestern Louisiana, included the Sibley, Ada, and Sailes petroleum fields and parts of the Minden basin. The Minden basin, bounded on all sides by anticlinal petroleum fields, contains the Vacherie, Bistineau, Minden, Gibsland, and Arcadia salt domes. The Sligo and Trinity formations (Lower Cretaceous) are considerably thicker in the basin than on the anticlines, and the age of the units with maximum thickness changes varies with each subbasin. In contrast, the Jurassic and early Lower Cretaceous beds are thicker over the anticlines. This reversal of thickening with time involves two stages of development. In the Jurassic, an elongated, esker-shaped salt pillow developed along the axis of the present basin, and ontemporaneous Jurassic salt withdrawal formed a peripheral sink in the area of the anticlines. During the Early Cretaceous second stage, salt stocks developed by cannibalizing the salt accumulated in the pillows, thereby lowering the thinned Jurassic section. Thus the thickened Jurassic section in the peripheral sink became an area of structural highs or anticlines compared to the Minden basin.

The major movement of the Vacherie salt dome was during the Early Cretaceous as indicated by the larger rim syncline development, steeper dips, and greater thinning than in the Late Cretaceous and Tertiary. At the Gibsland and Bistineau salt domes, data are considerably more sparse, but the presence of large Early Cretaceous rim synclines suggests a similar history.

AAPG Search and Discovery Article #90972©1976 AAPG-SEPM Annual Convention and Exhibition, New Orleans, LA