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

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

GEOLOGICAL MAGAZINE

CAMBRIDGE UNIV PRESS

Año: 2018 p. 1 - 10

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.