Delineation of the boundaries of San Blas basin, Mexico, merging gravity, magnetic, and seismic data

Abstract

The San Blas Basin (SBB) is located within what is referred to as the Mazatlán Basin, in the offshore west of Mexico. The SBB is positioned in the southern part of the Mazatlán Basin, within a region that remains poorly understood. Specifically, details about its shape and size are currently unknown, and only a few studies have provided some understanding of its limits. To ascertain the extent of the SBB and define its boundaries, we employed satellite-derived gravity and magnetic models, along with analyses linked to these fields. We established structural continuity through spectral analyses of gravimetric and magnetic data and the interpretation of various published seismic profiles in the near area. We also applied various filtering techniques, including the removal of regional trends and the regional Gaussian filter. Some anomalies of the potential fields are repeatedly reproduced in the different processed maps. These features allow for a comprehensive geophysical interpretation of the area under consideration, which leads to the proposal of the boundaries of the SBB. Additionally, 3D inversions of gravimetric and magnetic data were carried out in the study area. From these data, a more detailed response was observed in the 3D gravimetry than in the 3D magnetometry. In the former, it was possible to characterize a series of high-density and low-density bodies that were arranged in defined orientations, which were associated with the migration processes of Baja California from its position 30 Ma to its current position. A pattern of progressive evolution of the basin is given, from 30 Ma to the Present.