Geophysical modeling of the crustal boundary between the Central and Oaxaquia terranes in northern Mexico

• Published in: Journal of South American earth sciences 2021-10, Vol.110, p.103288, Article 103288
• Main Authors: Pérez-Aguirre, Xavier J., Chávez-Cabello, Gabriel, Ramírez-Peña, César Francisco, Méndez-Delgado, Sóstenes, Romero-de la Cruz, Oscar Mario
• Format: Article
• Language: English
• Subjects: Central and Oaxaquia terranes; Crustal boundary; Geophysical modeling; Magnetic and gravity anomalies
• ISSN: 0895-9811; 1873-0647
• DOI: 10.1016/j.jsames.2021.103288

On the boundaries of the states of Coahuila and Zacatecas in northern Mexico, scarce outcrops of a Triassic subduction complex have been used to infer in several positions a tectonostratigraphic terranes boundary. This crustal boundary is covered by a pile of Jurassic volcanosedimentary rocks and a thick, folded, and thrusted Mesozoic sedimentary marine succession. We carried out detailed mapping, geological cross-sections, and a geophysical survey using magnetic and gravity data to model the buried boundary between these crustal blocks. Qualitative analysis of the magnetic and gravity anomalies was performed in order to determine the crustal boundary. It was integrated with in situ rock magnetic susceptibility and density data obtained in the laboratory to restrict the inversion process. The calculated models helped us to better constrain a regional structural lineament, named Las Norias fault. This fault divides two cortical blocks, the Central terrane and Oaxaquia microcontinent, whose physical properties and styles of deformation in the Mesozoic cover are very contrasting. •Analysis of geophysical and geological field information.•Modeling of gravity and magnetic anomalies by joint inversion techniques.•Estimation of the geophysical parameters density and magnetic susceptibility.•Recognizing the inferred boundary between the Oaxaquia microcontinent and Central terrane.