First geochemical and geochronological characterization of Late Cretaceous mesosilicic magmatism in Gastre, Northern Patagonia, and its tectonic relation to other coeval volcanic rocks in the region

ORTS, DARÍO; GIACOSA, RAÚL; PUIGDOMENECH NEGRE, CARLA; LAGORIO, SILVIA; NIETO, DIEGO SILVA; BOLTSHAUSER, BÁRBARA; HALLER, MIGUEL; ZAFFARANA, CLAUDIA; BUSTEROS, ALICIA; RUIZ GONZÁLEZ, VÍCTOR; SOMOZA, RUBÉN

GEOLOGICAL MAGAZINE

CAMBRIDGE UNIV PRESS

Año: 2019 vol. 156 p. 1285 - 1294

0016-7568

This work characterizes Late Cretaceous calc-alkaline volcanic rocks in Gastre, Northern Patagonia, Argentina. These newly found porphyritic rocks bear an 40Ar-39Ar amphibole age of ~ 74-76 Ma, a subduction-type geochemical signature and a deep, garnet-bearing source. Extruded in a stage of low magmatic activity in the Northern Patagonian Andes (~ 41-44° S), they could represent an eastward migration of the Late Cretaceous magmatic arc that was associated with a regional compressive deformational stage in the South American margin.