Transgressions and Regressions in the Barataria Bight Region of Coastal Louisiana

LEVIN, DOUGLAS, R., Bryant College, Smithfield, RI

A literature review of Mississippi River delta lobe chronologies revealed a paucity of stratigraphic information in the Barataria shoreline area between Caminada/Moreau headland and Point Chenier Ronquille. The geologic history of this part of the Louisiana delta plain has since been determined using a database that includes nearly one hundred vibracores, high-resolution seismic data, carbon-14 dates, scrutiny of historical maps, and a consolidation of regional investigations conducted by other researchers. The refinement of the Mississippi delta lobe chronology is of primary interest to researchers of coastal Louisiana.

At least three delta progradations have contributed to the Barataria geologic framework since 5000 years ago. The Bayou des Families lobe (4600-3600 years ago) was first followed by Bayou Blue (2600 and 1900 years ago) and then the Mississippi lobe (1000 years ago to the present). The newer dataset suggests that the des Families lobe is older and the life span of the Bayou Blue lobe significantly longer than previously thought. The age of the Mississippi River lobe agrees with past researchers with the exception that the newer data allowed recognition of an early and late phase of lobe construction.

A flooding surface separates the (lower) Bayou des Families lobe from the Bayou Blue progradation (above). The shoreface of the Bayou des Families transgression lies seaward of the present Barataria shoreline. This transgression lasted approximately one thousand years. A flooding surface also separates the (lower) Bayou Blue progradation from the Mississippi delta lobe (above). This (Bayou Blue) transgression lasted 900 years, stopped near the present shoreline, and can be traced from the Caminada headland to the meander bend of the Mississippi River at Nairns, Louisiana. Grand Terre barrier island is part of a strand plain formed during the abandonment phase of the Late Mississippi delta lobe progradation. Grande Isle lies slightly seaward of Grand Terre. It was formed following the rogradation of a delta lobe (late Lafourche) on the western margin of the Barataria region.

AAPG Search and Discovery Article #91006 © 1991 GCAGS and GC-SEPM Meeting, Houston, Texas, October 16-18, 1991 (2009)