Tectono-sedimentary evolution of Southern Mexico. Implications for Cretaceous and younger source-to-sink systems in the Mexican foreland basins and the Gulf of Mexico

Abstract

An extensive dataset of existing and new geo/thermochronological data from several areas in Southern Mexico constrains the tectonic history of the region, as well as various source-to-sink relationships and local burial histories. Our interpretation acknowledges that not all cooling/heating observed in the source areas is due to erosional exhumation/burial but, in some cases, due to advective heat transfer from magmatic sources, which potentially overprinted earlier events. In this work, we identified several areas that have been exhumed since the Early Cretaceous and potentially provided clastic material to the southern Gulf of Mexico area.We help to document how the Mexican (Laramide) Orogeny propagated eastwards and southwards from the Late Cretaceous through the early Oligocene. The first sediments reaching the Tampico–Misantla and Veracruz basins derived mostly from eroded Cretaceous carbonate material that covered the Sierra Madre Oriental, the Sierra de Juárez Complex and the Cuicateco belts, as well as foredeep/intra-orogenic basin deposits formerly covering them. Possibly by the end of the Mexican Orogeny, the clastic Jurassic and older crystalline basement rocks became exposed and became the main sources of quartz-rich clastic material to the most easterly foreland basins and Gulf of Mexico. Exposure was probably assisted by higher angle basement thrusts such as the Vista Hermosa/Valle Nacional faults. The Mixtequita and Guichicovi blocks have also provided an important source of quartz-rich and metamorphic lithic-rich material to the southern Veracruz Basin possibly since the Eocene.For most of the Cenozoic, the Chiapas and the Sureste basins were sourced from areas south of the Chiapas Massif, i.e., the North America–Caribbean plate boundary zone along today's Chiapas coastal plain. This plate boundary zone accommodated relative displacement between Mexico and the Chortis Block of the Caribbean Plate. Paleocene–middle Miocene sediments within the Chiapas Basin were at least partially sourced from i) metamorphic complexes in the northern Chortis Block; ii) the parautochthonous Chontal Complex, an oceanic-like basin sandwiched between Chortis and southern Mexico; iii) the elongating volcanic arc along southern Mexico and western Chortis; and iv) the Cretaceous and Jurassic sedimentary cover of the southern flank of the Chiapas Massif,The westward telescoping of southern Mexico onto the Cocos Plate in the wake of Chortis has produced flat slab subduction geometry and eastwardly-younging uplift of the Xolapa Belt (Oligo–Miocene) and the Chiapas Massif (late Miocene). It also caused reorganization of the drainage systems providing material to the Chiapas and Sureste basins.Our results highlight the importance of understanding relative block and plate boundary displacements in a dynamic hinterland and consider the role of major faults when interpreting source-to-sink relationships in the area. We describe the latter relationships for several geologic time intervals in which reservoir-prone sediments were delivered to the southern Gulf of Mexico. Finally, we integrate the source-to-sink history to provide an assessment of reservoir quality and hydrocarbon prospectivity in the region.