4.1 Zircon U-Pb dating
We obtained 5 new zircon U-Pb ages for the intrusions of the Western Cordillera ranging from 23.9 ± 0.7 to 15.4 ± 0.5 Ma (Fig. 3A; Table 1; Fig. S1). Zircon U-Pb ages from the Apuela Nanegal intrusion in northern Ecuador are 23.9 ± 0.7 (987 m) and 15.4 ± 0.5 Ma (1676 m). In central Ecuador the zircon U-Pb age of the Telimba Chazo Juan intrusion is 21 ± 0.6 Ma (2086 m). In southern Ecuador the zircon U-Pb ages for the Gaby-Papa Grande intrusion and the Chaucha intrusion are 22.7 ± 0.5 Ma (683 m) and 16.9 ± 0.4 Ma (2578 m), respectively.