DELINEATION OF CRUSTAL DOMAINS IN THE NORTHEASTERN GULF OF MEXICO FROM INTEGRATED GEOPHYSICAL ANALYSIS

The Gulf of Mexico (GOM) is a semi-enclosed basin located in the southeastern corner of North America. The GOM basin contains one of the largest petroleum provinces of the world. Current tectonic models agree that the basin opened in three stages. It initiated as a continental rift in the Late Triassic followed by a short period of salt deposition. Between the Jurassic and Early Cretaceous, sea floor spreading started and the Yucatan block rotated counter clockwise away from North America, splitting the initial salt deposits into the northern and the southern provinces. Sea floor spreading ceased in the Early Cretaceous when the Yucatan block docked against southern Mexico. Later, the basin began to subside allowing the accumulation of Mesozoic and Cenozoic clastic sediments as well as the formation of carbonate platforms along the Florida and Yucatan margins. In spite of the majority of tectonic models agreeing on these three steps, the details are still being debated, such as location of the pole of rotation, timing of the salt deposition with respect to sea floor spreading and the location of Ocean-Continent Boundary (OCB). The primary objective of this study is to delineate crustal domains (oceanic and continental) based on the subsurface model, which agrees with all geophysical data available in the public domain.

In our study, we integrate satellite derived gravity and magnetics with seismic refraction data in the northeastern GOM. We built 2-dimensional potential fields model based on seismic refraction profile (GUMBO3) from Eddy et al. (2014) that extends from Pensacola, Florida, toward the center of the basin. We derived physical properties (densities and magnetic susceptibilities) for both continental and oceanic domains and determined the OCB location along that line. Then, we applied various filters to potential fields grids in order to highlight geological structures, such as OCB, the segments of an extinct mid-ocean ridge and transform faults. We combined those mapped geological features with our 2D subsurface model along GUMBO 3, which allowed us to expand our interpretation outside of seismic coverage. Similar analysis is anticipated for the adjacent GUMBO 4 (Christeson et al., 2014) profile. The result of our study will provide important constraints to the plate tectonic reconstruction of the GOM.