--> Potential Fields Modelling in the Northeastern Gulf of Mexico

AAPG ACE 2018

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Potential Fields Modelling in the Northeastern Gulf of Mexico

Abstract

The Gulf of Mexico is a semi-enclosed basin located in southeastern part of the North America. The thick sedimentary cover with complex salt structures obscures the seismic imaging of the crust, which challenges tectonic reconstruction of the basin. For this project, we have modelled potential fields (gravity and magnetics) along two seismic refraction profiles GUMBO3 and GUMBO4 (Eddy et al., 2014 and Christeson et al., 2014) in the northeastern Gulf of Mexico in order to delineate the deep crustal structures.

We used published gravity (Sandwell et al., 2014) and magnetics data (Meyer et al. 2017) to map ocean-continent boundary, extinct mid-ocean ridges, and transform faults in our study area. We built two-dimensional potential fields models (GUMBO3 and GUMBO4) and derived the densities and magnetic susceptibilities of the subsurface rocks. We assigned the same physical properties for the major geological layers in both models (seven sedimentary units, upper and lower continental/oceanic crusts and upper mantle). As a result, we traced major crustal structures in the study area, as well as obtained the thicknesses of various crustal layers in both models. By combing different geophysical data (seismic, gravity and magnetics), we were able to expand our interpretation of major geological structures outside of seismic coverage.

The integrated approach to geological and geophysical data analysis allowed us to reduce the uncertainty of our resultant subsurface models. The observed variations in the crustal units between the two profiles indicate the complexity of the tectonic settings, which needs to be taken into account during the basin restoration. Our study provides important constraints on the major geological structures in the northeastern Gulf of Mexico, which are crucial for the tectonic reconstruction.