Crustal Architecture, Cretaceous Rise and Igneous Activity of Sabine, Monroe and Jackson Uplifts, Northern Gulf of Mexico Basin

Structural highs and lows that formed during the Cretaceous resulted in regional angular unconformities in the northern onshore Gulf of Mexico Basin. Some of the uplifts, with varying size and amplitude, are located where Cretaceous magmatism occurred. The Sabine, Monroe and Jackson Uplifts were formed during this period. The rising of the Sabine Uplift during the Late Cretaceous created major traps for oil and gas accumulation in East Texas Field and natural gas plays have been discovered related with the Monroe and Jackson structures. The objectives of this study are: 1) to investigate crustal architecture of the area; 2) to locate subsurface Cretaceous igneous rocks; 3) to evaluate the Cretaceous tectonic events of the Sabine, Monroe and Jackson Uplifts; 4) to investigate the relationship between magmatism and uplift. To interpret these important structures and igneous bodies, gravity and magnetic anomaly data, and enhancements of these data were examined. Three 2D transects, ranging from 470 to 650 km-long, through the uplifts were constructed and modeled. Models were constrained by seismic, well and geological data. Our results suggest that the crystalline crust of the northern onshore Gulf of Mexico Basin was variably extended beneath the Sabine, Monroe and Jackson Uplifts. There is a thick crust beneath Sabine Uplift with a shallow basement and deep Moho. The thickness of the crust decreases to the south. From west to east interior basins are located between high standing structures and are characterized by thick accumulations of salt. Upper Cretaceous igneous activity modified and was superimposed upon the crustal and basinal structures. This activity was followed by partial erosion of the uplifted formations, resulting in angular unconformities. The Monroe and Jackson structures were locally uplifted during the Late Cretaceous. This age of uplifts and igneous rocks suggests that the rise of the structures during this time was associated with igneous activity. We interpreted the local rise of the Sabine Uplift, during the Woodbine and Eagle Ford Gulf Stages, as a result of the magmatism modeled in this study. Unraveling the complex relationship between this structuring and magmatism requires a solid understanding of the crustal architecture of the region.