3 Methods
Low-temperature thermochronology records the thermal history of the crust that can be related to exhumation and/or cooling/heating events. Exhumation can be, with supporting geological information, interpreted as the combined result of rock uplift and erosion. Zircon (U-Th)/He (ZHe), apatite fission track (AFT) and apatite (U-Th)/He (AHe) thermochronometers are sensitive to temperatures ranging from 200 to 20 °C (e.g., Ault et al., 2019). The thermal histories of Cuenca, Guaranda and Apuela regions in the Western Cordillera were determined using QTQt software, which inverts AFT annealing and AHe diffusion parameters for samples with an elevation relationship (Gallagher, 2012). We used zircon U-Pb geochronology conducted at the Arizona LaserChron Center and published data (Schütte et al., 2010) to determine the crystallization ages of intrusions and as a constraint for thermal modeling. Additional methodological details can be found in Supplemental Data (Text S1; Tables S1, S2).