Subsidence and Heat Flow Across a Sedimentary Basin-Uplift Boundary: A Thermal-Mechanical Model: ABSTRACT

Abstract

The northern coast of the Gulf of Mexico contains major depositional basins in east Texas, north Louisiana, and central Mississippi. They are separated by the Sabine and Monroe uplifts. Basin subsidence can be interpreted as resulting from extension by rifting related to opening of the Gulf of Mexico during Late Triassic to Early Jurassic times. Subsidence of the North Louisiana salt basin, determined from well data, is consistent with crustal extension by a factor of 1.5 to 2. Seismic surveys across End_Page 526------------------------------ the East Texas and Central Mississippi salt basins also indicate thinned crust. Thus, a probable explanation for the intervening Sabine and Monroe uplifts is that they represent areas of unstretched or only slightly stretched lithosphere. This juxtaposition of thermally perturbed lithosphere with unperturbed or only slightly perturbed material is similar to interactions between oceanic crust of different ages across a fracture zone. A thermal-mechanical model describing lateral conduction of heat and mechanical coupling of the lithosphere across this boundary is presented. Effects of finite extension rate, increasing mechanical thickness with age as the lithosphere cools, and thermal blanketing by overlying sediment are included. Subsidence history, heat flow, and sedimentary stratigr phy predicted from this model are compared with observational data. End_of_Article - Last_Page 527------------