MECHANISMS OF ASCENT AND EMPLACEMENT OF THE INTRUSIVE SAN FELICIANO,MAZAPIL,ZACATECAS

The study was focused on the geological mapping and structural analysis of a set of igneous intrusive structures and their encasing rocks, which together make up the San Feliciano Intrusive Complex. The objective was to identify the magma location mechanism (s), and their temporal location relationship with respect to the development of the regional fold in which they are housed, called Anticlinal Santa Rita. In general, the main igneous structures that make up the ISF are represented by two sub-volcanic bodies, connected by small dikes and separated by walls of encasing rock affected by contact metamorphism and metasomaticism.

The ISF is located on the front flank and core of the Santa Rita Anticline, which is made up of marine sedimentary rocks whose age varies between the Upper Jurassic and Upper Cretaceous. On the western flank of this fold, the sedimentary rocks lie in a normal position, while the eastern flank is inverted, constraining to an overturned fold with typical characteristics of a vergent fault propagation fold to the east, similar to regional structures generated by deformation. thin-skinned during the late Cretaceous in the area. The occurrence of interconnected dikes and sills, as well as a large magnetic anomaly in the central zone of the study area (San Feliciano valley), suggests the existence of a buried igneous stock, whose upper part partially outcrops in the area, constricting a “Christmas tree” type structure, located after the generation of the regional fold that contains it.

The presence of encasing rock screens within the intrusive indicates that the magmatic recess was an important emplacement mechanism for the magma that generated the ISF. In addition, the presence of the magnetic anomaly in the San Feliciano valley, on the nucleus and front flank of the Santa Rita anticline, indicates that the lifting of the roof and subsequent subsidence were also important mechanisms that controlled the development of the space for the site of the magma.