New thermocronological data of the Cretaceous-Cenozoic clastic sequences from the VINCHINA basin: Linkage between burial, exhumation and thermal flow variations

WUNDERLIN, CECILIA; COLLO, GILDA; PARRA, MAURICIO; EZPELETA, MIGUEL; SÁNCHEZ NASSIF, FRANCISCO; FLORES, MARLENE; SOBEL, EDWARD R.; GLODNY, JOHANNES

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2021 vol. 105

0895-9811

New apatite fission track (AFT) and (U?Th)/He (AHe) data from two sections recording Cretaceous-Cenozoic clastic successions (La Flecha - La Troya Sur creeks) in the northern sector of the Central Precordillera of Argentina are presented. The results show that the Ciénaga del Río Huaco, Puesto la Flecha and Vallecito Fms. would have crossed the 60 °C isotherm during burial, while the middle sector of the Vinchina Fm. would not have reached temperatures higher than 55 °C. Multimethod inverse thermal modeling suggests that the AFT ages of all the studied levels would not have been completely reset and allow inferring that the partial retention zone for the AHe system (AHe-PRZ) would have been reached during the Miocene in levels between the Vallecito and Vinchina Fms. Our 1D-modeling results for the Ciénaga del Río Huaco, Puesto la Flecha and Vallecito Fms. show that the maximum temperature would have been reached at ~15 Ma, with a sedimentary thickness of ~2750 m and a heat flow of 65 mW/m2. From these data, a geothermal gradient of ~27 °C/km at this time could be inferred. In turn, the Vinchina and Zapallar Fms. would have reached their maximum temperature at ~2 Ma, under a cooler thermal regime (20 mW/m2) and with an estimated geothermal gradient of