ABSTRACT

A biostratigraphic study of south-central Lafourche Parish, Louisiana, was undertaken to solve some of the structural and stratigraphic problems of the area. Wells were examined paleontologically from Valentine, Bully Camp, Golden Meadow, Leeville, and Bayou Raphael Fields in Lafourche Parish. One well was examined from Bayou Jean LaCroix Field in eastern Terrebonne Parish. Results of these paleontological examinations served as the principal source of regional correlations; electrical logs were also used at key locations when samples were not available, or were not collected from high enough in a well for the uppermost regional occurrence of index forms to be observed.

A restored stratigraphic dip section illustrating downdip thickening, and a stratigraphic strike section demonstrating the essentially horizontal nature of the beds, were constructed. A structural cross-section through the Golden Meadow Field illustrates a graben and fault pattern typically associated with a deep-seated salt mass.

As defined in this study, the "Eggerella Wedge" and the "second" Cibicides carstensi zone are useful horizons south of a zone of flexure found between the west flank of the Golden Meadow Field and the south flank of the Bully Camp Field. This zone of flexure may be traced downdip. Sediments above the trace are "plate-like" continental shelf deposits and are easily correlated; those below the trace are continental slope deposits and extremely difficult to correlate because of the great thickening and gross lithologic changes which take place in this zone.