Thermochronological modeling in Cretaceous-Cenozoic sequences from the northern sector of the Neuquén basin: contributions to the understanding of regional thermal evolution

Abstract

This study presents new thermochronological data and models for the Cretaceous–Pliocene in the northern Neuquén Basin, Argentina. Samples were collected from the Huitrín, Rayoso, Diamante, Saldeño, Pircala, and Agua de la Piedra formations in the Arroyo Las Aucas section (eastern sector) and the Vega Grande and Vega de los Patos sections (western sector). Apatite (U–Th)/He (AHe; 4.7–53.3 Ma) and fission-track (AFT; 108–217 Ma) ages indicate partial to complete annealing. Thermochronological modeling reveals distinct thermal episodes in both sectors. In the western sector, heating is recorded during deposition of the Huitrín and Rayoso formations (Lower Cretaceous). AFT ages from the Rayoso Formation may alternatively reflect inheritance from volcanic sources or partial resetting, in which case maximum temperatures were reached either (1) during burial of the Diamante Formation, or (2) prior to the deposition of the Diamante Formation and related to a thermal anomaly. Subsequent thermal stability persisted until ~20 Ma, followed
by cooling associated with exhumation and deformation in the Malargüe fold-and-thrust belt. In the eastern sector, unreset AFT and AHe ages suggest thermal stability between ~60 and 40 Ma, followed by heating from ~20 Ma linked to deposition of the Agua de la Piedra Formation, and subsequent cooling (~13–10 Ma). These results highlight the complex interplay among sedimentation, heat flow, and tectonics along the northern margin of the Neuquén Basin.