Geochemical fingerprints and tectonic setting of the Late Palaeozoic marginal basin of the Bariloche Complex (SW Gondwana), North Patagonian Andes of Argentina

A micaschist of the VR yielded a U-Pb detrital zircon maximum depositional age of 358 ± 4 Ma (2σ). Moreover, a ²⁰⁶Pb/²³⁸U preferred age of 330 ± 6 Ma is likely explained by a mixed isotopic signal resulting from a late metamorphic/thermal overprint, or Pb loss in the metasediment zircons. These results, compared with neighbouring Late Palaeozoic regions, constrain the lifetime of a back-arc basin until its closure at the beginning of the Gondwanide orogeny.</p> <p></p><p>Inmature detritus fills the back-arc marginal basin.</p><p>Basaltic protoliths have N-MORB, E-MORB and OIB signatures.</p><p>The mica schist of the BC yields a maximum depositional age of 358 ± 4 Ma.</p><p>The 330 ± 6 Ma age likely reflects metamorphism or isotopic mixing.</p><p></p> <p>Inmature detritus fills the back-arc marginal basin.</p> <p>Basaltic protoliths have N-MORB, E-MORB and OIB signatures.</p> <p>The mica schist of the BC yields a maximum depositional age of 358 ± 4 Ma.</p> <p>The 330 ± 6 Ma age likely reflects metamorphism or isotopic mixing.</p>