Provenance analysis of Oligocene sandstone from the Cerro Pelon area, southern Gulf of Mexico

摘要

In southeastern Mexico, Jurassic and Cretaceous rocks are buried beneath voluminous Palaeogenesedimentary successions, the origin of which is still under debate. Some authors proposed that these Palaeogene successions were derived from Proterozoic, granulite-facies rocks of Oaxaquia, a microcontinental block exhumed during a Late Cretaceous-Palaeogene orogenic event driven by variations in convergence rates along the Pacific margin of North America. Alternatively, other authors suggested that these successions were mostly derived from the Guatemala suture complex, which contains eclogite- to greenschist-facies metamorphic rocks that were exhumed along the Caribbean-North America plate boundary during latest Cretaceous and Palaeogene time. In order to test these scenarios, we present new petrographic data, chemical analysis of detrital heavy minerals, and U-Pb ages of detrital zircons to clarify some aspects on the origin of Oligocene sandstones exposed in the Cerro Pelon area, southeastern Mexico. Our data indicate that the studied sandstones were mostly sourced from eclogite- to greenschist-facies metasedimentary, metaigneous, and ultramafic rocks of the Guatemala suture complex. Minor contributions from the Chiapas Massif Complex exposed directly to the south of the Cerro Pelon area are also documented. Based on these data, we conclude that the accumulation of at least part of the Palaeogene stratigraphic record in southeastern Mexico was mostly controlled by the development of the Caribbean-North America plate boundary rather than by orogenic processes at the Pacific margin of North America.