GULF OF MEXICO BASIN OPENING (GUMBO): A SEISMIC STUDY OF THE TEXAS GULF COAST

The Gulf of Mexico, a small oceanic basin, formed by rifting between the continental blocks of North America and Yucatan in the Middle to Late Jurassic (165 Ma). The margins of the continents stretched and thinned before they separated but the extent of stretching and thinning is unknown. After the breakup, seafloor spreading formed volcanic crust in the central Gulf of Mexico and then, in the Early Cretaceous (140 Ma), opening between North America and Yucatan stopped. Subsidence and sedimentation subsequently shaped the Gulf margin that we see today.

Despite decades of seismic exploration in the Gulf of Mexico and along its margins, the region’s lithospheric structure is not yet imaged in detail. As a result, we do not know how the continental crust of North America tapers towards the Gulf, how subsidence is accommodated by the brittle crust, precisely where the transition from continental to oceanic crust is located, nor how the lithospheric mantle and asthenosphere have accommodated, or participated in, stretching and thinning.

A new geophysical transect across the Gulf of Mexico’s Texas margin has been undertaken that will produce strong seismic, gravity and magnetic constraints on current lithospheric structure. Goals are to provide insight into the mechanics of continental breakup, the role of rift architecture on the post-rift structural development of this margin, and the role of the lithospheric mantle in crustal breakup. Preliminary results from this study will presented.