Provenance of Carboniferous-Permian sedimentary units in southern Mexico: evidence for peri-arc basin evolution during the Pangea assembly

ABSTRACT

The Oaxacan Complex Carboniferous-Permian sedimentary cover in southern México records provenance shifts through time, reflecting the collision between Gondwana and Laurentia to amalgamate Pangea. The integration of petrological analysis and LA-ICP-MS U-Pb zircon geochronology from Santiago, Ixtaltepec and Yododeñe formations compared with adjacent terranes suggests that: (1) during the Early Mississippian, the Santiago Formation received sediments mainly from local sources such as the Oaxacan Complex and Tiñu Formation, with minor contributions from adjacent peri-Gondwana sources. The magmatic activity may have started during this time (~359–346 Ma) (2) during the Late Mississippian (Ixtaltepec Formation), detrital zircon grains of Ediacaran-Cambrian age are dominant, derived from sediments either related to the Pan-African/Brasiliano orogeny or the opening of the Iapetus Ocean; (3) during the Late Mississippian-Middle Pennsylvanian, intercalated marine volcaniclastic sandstone (Ixtaltepec Formation) provides the first record of Carboniferous arc-related volcanism reported in southern Mexico, dated between 330 and 308 Ma; (4) the early Permian Yododeñe Formation records the exhumation and erosion of the sedimentary cover during the final stage of Pangea assembly. Rhyodacitic subvolcanic sills and lavas dated at ~282–270 Ma are present throughout the succession. Volcanism and ca. 360–308 Ma detrital zircon grains could be associated with a Carboniferous magmatic arc formed by subduction of the Rheic oceanic plate beneath Gondwana. Slightly younger detrital zircon and subvolcanic rocks dated at ~300–270 Ma are linked to a western Pangea arc developed in response to the subduction of the Paleo-Pacific Ocean following Pangea assembly. Our results suggest that the Carboniferous-Permian units were deposited in a peri-arc basin, sharing sediment provenance with the Maya and Coahuila blocks, the Sierra de Juárez Complex, and northwestern South America.

KEYWORDS:

• Gondwana
• Laurentia
• Pangea
• southern México
• Carboniferous
• Permian
• Oaxacan complex
• provenance analysis
• geochronology
• detrital zircon

Acknowledgments

The first author acknowledges the Consejo Nacional de Ciencia y Tecnología (CONACyT) for granting her PhD scholarships. This contribution was financed by Conacyt Ciencia de Frontera grant #7351 “The opening and closure of the Rheic ocean as seen from Mexico: a stratigraphic, isotopic and geochronologic approach” to Luigi A. Solari, who funded this study; and a DGAPA-UNAM Postdoc scholarship granted to Roberto Maldonado. We also thank Juan Tomás Vázquez Ramírez for thin section preparation; Irene Pérez for helping with mineral separation; Mónica Ramírez-Calderón, Juan Carlos Castillo, and Guillermo Espejo-Bautista for helping during field work. We are grateful to reviewers Dr. Damian Nance, Majie Fan, and an anonymous reviewer for careful and fruitful comments to improve this paper.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00206814.2023.2175270

Additional information

Funding

This work was supported by the Consejo Nacional de Ciencia y Tecnología [7351].