ABSTRACT

Regional thermal and Time-Temperature Index (TTI) contours were prepared for 12 dip paleo-temperature restorations extending from central Arkansas to the central Gulf Basin. The first 9 restorations are based on back-stripping of Series- long sequences above the Louann Salt with the salt not restored. Additional reconstructions through Lower Jurassic set a geologic scenario prior to continental rifting.

The restorations with salt not restored reveal that a paleo-Sigsbee salt wedge, undergirding the Upper Jurassic to Pleistocene continental slope, has been a "permanent" ocean-side feature of the prograding margin, a salt-sediment geometry not in existent salt tectonic theories. Such a permanent, and laterally, migrating "salt nose" provides an obstacle against which feature descending gravity-driven protruding salt structure. The nose migration has left a lubricating layer of salt welds and other features. This salt-surrounded unit, beneath and down-dip, may be termed a "salt-floored sub-basin" containing mostly "shallow" sediments of coastal plain, shelf, and slope genesis, and growing through time.

By Lower Cretaceous (131-96 MY) times, the salt-floored basin, updip from the then Sigsbee salt wedge, was deep enough, approximately 5 - 7 km, that hydrocarbon maturation had begun. In the Upper Cretaceous (96-66 MY), hydrocarbon maturation extended to sediments along flanks of the recently extinct mid-ocean ridge. From then to the present, ever more of the sedimentary volume has been subject to maturation. basin evolution, Gulf of Mexico, salt floored basin, salt extrusion, time-temperature indices (TTI), thermal evolution