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).