Boletín de la Sociedad Geológica Mexicana
Volumen 67, núm. 2, 2015, p. 285-297
Revisión de los últimos eventos magmáticos del Cenozoico del sector norte-central de la Sierra Madre del Sur y su posible conexión con el subsuelo profundo de la Cuenca de México
Enrique Alejandro González Torres1,*, Dante J. Morán Zenteno2, Laura Mori1, Barbara M. Martiny2
1 División de Ingeniería en Ciencias de la Tierra, Facultad de Ingeniería, Universidad Nacional Autónoma de México, Ciudad Universitaria, Código Postal 04510, México, D.F., México
2 Departamento de Geoquímica, Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Código Postal 04510, México, D.F., México.
In this work we review the possible correlation between the deep subsoil units of the Mexico Basin (MB), that are known through the lower successions cut by wells, and the Cenozoic stratigraphic record previous to the Trans-Mexican Volcanic Belt (TMVB), which is exposed in the northern part of the Sierra Madre del Sur (SMS). South of the MB, recent stratigraphic studies provide new geochronological data from some eruptive centers of the northern-central sector of the SMS, such as the Taxco and Huautla volcanic fields, and the Tilzapotla caldera. These volcanic fields represent the last volcanic record of the Paleocene SMS arc that developed before the inception of the TMVB. Based on lithological analogies, the stratigraphic position and the thickness of the obtained lithological record, the lower parts of the deep wells drilled in the MB can be related to the distal units of the previously mentioned volcanic centers. In the same way, in Tepoztlán and Malinalco (states of Morelos and México), located south of the MB, the first volcanic episodes of the TMVB are exposed, with ages ranging from ~22.8 and 18.8 Ma, that have been correlated by other authors to the ages reported in various deep wells of the MB.
Based on the available geologic information, we consider that the process of subsidence observed in the MB is contemporaneous with the TMVB, and that it is not related to the Paleogene tectonics of the region. The absence of significant volumes of volcanic or sedimentary rocks of probable Paleogene age (generally less than 1000 m thick) between the Neogene successions and the Cretaceous marines units in the MB subsoil, strongly suggests that subsidence mainly took place during the Neogene.
Keywords: Mexico Basin, Trans-Mexican Volcanic Belt, Sierra Madre del Sur, well records.