Cenozoic cooling history of the San Francisco–Lambrama region, Andes of South Peru, through fission‑track thermochronology and U-Pb geochronology

van Heiningen P.S.; Carlotto V.; Donelick R.; Zuloaga-Gastiaburu A.D.; Kaymakci N. · International Geology Review (2026) · DOI: 10.1080/00206814.2026.2692493

Resumen

To unravel the Cenozoic cooling and exhumation history of the Apurímac River drainage basin, samples were collected from the Western Cordillera, Eastern Cordillera, and the northern margin of the Northern Altiplano in South Peru and subjected to AFT, ZFT, and A(U-Pb) and Z(U-Pb). In the Eastern Cordillera, cooling ages are concentrated between ~8 and 1 Ma, reflecting Late Miocene to Pliocene exhumation. In contrast, the Western Cordillera and the northern rim of the Northern Altiplano record earlier cooling between ~23 and 6 Ma, indicating significant exhumation already during the Oligocene to Late Miocene. These results demonstrate strong spatial variability in the Cenozoic cooling history of the region and indicate differential exhumation both between and within the cordilleras. The thermochronological data further provide new stratigraphic constraints for continental red-bed deposits near Puente Pasaje previously interpreted as Triassic to Paleogene. The new data indicate a Miocene age, leading to the definition of a new stratigraphic unit, the Pasaje Formation. Overall, the results indicate that Cenozoic cooling and exhumation in the San Francisco–Lambrama region were strongly controlled by reactivation and inversion of regional fault systems, producing rapid and spatially differential uplift and denudation across the southern Peruvian Andes.

Instituciones: Universidad Nacional de San Antonio Abad del Cusco