CRETACEOUS-PALEOGENE GEOLOGICAL HISTORY OF MEXICO (Invited Presentation)

The Cretaceous-Paleogene geology of Mexico is significantly influenced by the Mexican orogen, which extends from northern Mexico to Guatemala. It comprises the Guerrero terrane in western Mexico (hinterland), highly strained rocks of the Arperos basin (suture zone) in central Mexico, and the Mexican fold-thrust belt in the foreland. Cordilleran tectonics are evident in the rocks and structures of these features, with temporal and spatial connections among them. Much of their history is preserved in primary features of sedimentary and igneous rocks, as well as secondary deformational structures and low-grade metamorphic rocks.

The Guerrero Terrane formed near the Pacific margin, while the Arperos basin subsided and accumulated sediments from the Guerrero terrane and carbonate platforms that formed in eastern Mexico during the early Cretaceous. Shortening deformation in the Guerrero Terrane occurred in the Aptian or earlier, eventually propagating to the Arperos Basin in the Albian, and later transferring eastward in the Cenomanian, progressively and episodically advancing towards the foreland fold-thrust belt by the Eocene. Shortening propagated intermittently into Chiapas and Guatemala until the Paleogene, due to the area's deep-seated lithospheric faults which bifurcated the Mexican fold-thrust belt around southern Mexico crystalline basements, further segmenting it to the south.

In addition to crustal heterogeneities across Mexico, significant variations in subduction dynamics from northern Mexico to Guatemala resulted in varied deformation styles, syn-tectonic sedimentation, and magmatism observed in central-northeastern Mexico, Veracruz-Oaxaca, and Chiapas-Guatemala areas, as will be detailed in the presentation.