Isotopic and thermochronologic evidences of an extremely cold lithosphere associated with slab flattening

COLLO, G., DÁVILA, F.M., TEIXEIRA, W., NÓBILE, J.C., SAN´T ANNA, L., CARTER, A.

BASIN RESEARCH

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017

0950-091X

We present mineralogic, isotopic and thermochronologic analyses on psammopelitic andtuffaceous levels from the Bermejo and Vinchina basins ? both foreland depocentres of theCentral Andes of Argentina ? that define a low-temperature regime for the crust akin to a slabshallowing and flattening process. The contents of illite in illite/smectite interstratified (I/S)show a progressive illitization into the deeper parts of both basins. The distribution of I/S iscompatible with theoretical simulations and predicted heat flow values of ca.26mWm2in the8?3.4 Ma interval for the Vinchina Basin and ca.42mWm2since 9 Ma for the BermejoBasin. The latter shows heat flow values that are comparable to those reported by magnetotel-luric analysis (36?40 mW m2) in agreement with previously published heat flow calculationsalong the modern Andean foreland. The Rb?Sr isochrones in psammopelites (