New fission-track results from the northern Chiapas Massif area, SE Mexico: trying to reconstruct its complex thermo-tectonic history
The Chiapas Massif Complex, which represents the crystalline basement of the southern Maya block within the North American plate, records numerous thermo-tectonic and magmatic events that occurred in southern Mexico at least since the late Mesoproterozoic. The present study was performed across the northern Chiapas Massif region to reconstruct its complex thermo-tectonic history from Mesozoic to present times. Basement samples and sandstones of the San Ricardo Formation derived from the Chiapas Massif Complex source area were analyzed by in situ apatite fission-track dating. The new fission-track results obtained in this study, together with previously published data, indicate that the Chiapas Massif Complex, or rather the whole Maya terrane, have experienced a complex long-term geodynamic evolution with at least five post-Permian tectonic and magmatic events: (1) a Late Triassic cooling event, likely related to the initial breakup of Pangea; (2) Early Jurassic volcanism that can be linked to the Nazas volcanic arc; (3) a Middle Jurassic tectonic event that was triggered by continental rifting at the beginning of the opening of the Gulf of Mexico; (4) a Late Cretaceous to Paleocene orogeny that may actually represent the southernmost continuation of the Laramide sensu lato which affected central and northern Mexico; and (5) the middle–late Miocene Chiapanecan event that is tectonically controlled by the interaction of the North American, Caribbean, and Cocos plates. This interpretation could be useful towards a better understanding of the geological history of southern North America. Some recommendations on sampling and analytical strategies are also given for consideration in further thermochronological studies in Chiapas.