Tectonics associated with the late Oligocene to early Miocene units of the High Andes (Cura Mallín Formation). A review of Geochronological, thermochronological and geochemical analyses

EDUARDO ROSSELOT; MARÍA HURLEY; SAGRIPANTI, LUCÍA; LUCAS FENNELL; SOFIA IANNELLI; DARÍO ORTS; ALFONSO ENCINAS; LITVAK, VANESA; ANDRES FOLGUERA

Opening and closure of the Neuquén Basin in the Southern Andes

Springer

Año: 2020; p. 386 - 403

The tectonic regime associated with the Oligo-Miocene Cura Mallín Formation and equivalents in the Main Andean Cordillera between 35° and 40°S, the Ventana and Abanico formations to the south and north respectively, is still matter of debate. While most authors have agreed in relating them to an extensional regime that could have interrupted Andean orogenesis, others have provided evidence of coexistence with an ongoing compressional regime at least for the upper part of their record. Available geochronological, structural, geochemical, thermochronological and basin subsidence data between 33° and 43°S are compiled and analyzed in this chapter in order to provide a tectonic framework for these rocks. Based on this analysis two different mechanisms seem to have succeeded through the accumulation of these sequences, a late Oligocene to earliest Miocene period characterized by synextensional deposits in an attenuated crust evidenced by low La/Yb ratios in contemporaneous magmatism, and a younger time period in the mid to late Miocene that coincides with regional exhumation and compression revealed by thermochronological data and syncontractional sedimentation