ABSTRACT

A tectonic and depositional model is presented for the North Louisiana-South Arkansas (NL-SA) Basin, extending from the up-dip sedimentary outcrop limit of the Mississippi Embayment, to the Sabine uplift and its possible eastward extension to the Wiggens Arch in the south, and lying between the Sabine and Monroe uplifts. Included in this designation is the North Louisiana Salt Basin.

Geohistory modeling of basin subsidence with time has been correlated to sediment deposition. The objective is to develop a dynamic model framework accurate enough to underpin individual prospects with regional understanding.

The tectonic chronology began with subduction in the middle Paleozoic, followed by rifting that is possibly part of mantle plume that rose in the upper Paleozoic. A second episode of magmatic intrusion associated with North Atlantic rifting occurred in middle Jurassic, with upper Jurassic seafloor spreading south of the Sabine uplift. Regional subsidence occurred from the edge of the Mississippi Embayment through the North Louisiana salt basin, including the proto-Sabine uplift. Thinning of salt indicates some relief in the late Jurassic. Early Cretaceous cessation of the central Gulf of Mexico spreading was accompanied by initiation of tectonic subsidence and the beginning of the South Louisiana salt basin. There was continued regional downdip from the edge of the Mississippi Embayment through the proto-Sabine uplift region. Mid-Cretaceous development of the Sabine and Monroe uplifts, with a reduction of subsidence rate in the NL-SA area, also impacted the evolution of sedimentary fill and associated structural evolution.