REVEALING THE FOREARC BASIN STRUCTURE OF THE BAJA CALIFORNIA PENINSULA THROUGH SEISMIC REFLECTION
The forearc regions are both the reflection and the host of tectonic convergence processes. In this context, the collaterally formed basins related to subduction are characterized by their considerable sedimentary thicknesses. The Baja California Peninsula hosts several forearc basins, resulting from the subduction event of the Farallon plate during the Late Cretaceous-Eocene. With this premise, we present a series of 9 land-based seismic reflection profiles provided by the petroleum industry, located in the Magdalena region within the Ciudad Constitución plain, in Baja California Sur. These profiles were processed and interpreted, and in conjunction with gravimetric data and well logs, they allowed the identification of prominent geological structures, including a forearc basin with a depocenter reaching a depth of 3000 ms (TVD) that formed between the former subduction zone and the roots of the volcanic arc. Additionally, an inverse fault with an apparent dip of 39° was interpreted, cutting through the sedimentary units of the region, and controlling subsidence in the basin. From a seismic-stratigraphic perspective, three seismic sequence boundaries were interpreted, two of which represent significant unconformities considered important geological features in the tectonic evolution of the region. The presented observations aim to enhance the understanding of the geological evolution of this region and, at the same time, generate subsurface images that allow for comparisons with analogous regions.