Abstract

Recently published work by Hervé et al. (2020) presents ten (10) new U–Pb detrital zircon ages from metamorphic units cropping out in the Chilean Coastal and Main Andean ranges between 28° and 33°S. The authors revise the age of metamorphic complexes and discuss the geodynamical context of this segment of the Andean margin during Late Paleozoic to Triassic times. A particularly controversial result is their suggested mid to late Triassic age for the El Tránsito Metamorphic Complex (ETMC). This new interpretation challenges previous work by Reutter (1974), Ribba et al. (1988), Álvarez et al. (2011), and Salazar et al. (2013, 2020), who consider the ETMC to have a Paleozoic or, more precisely, a Devonian-Mississippian age. Hervé et al.'s (2020) interpretation is supported by the maximum depositional age of 240–260 Ma for a metamorphic rock sample (FO10106) attributed to the ETMC. This proposal is, however, inconsistent with local stratigraphy and field relations. Here, we discuss the geological setting and review the geological and geochronological constraints supporting a pre-Pennsylvanian age of metamorphism for most of the metamorphic rocks included, so far, in the ETMC.