Geology and tectonic evolution of thecordilleran front at 36ª39'S: The Yihuin-Huaca y Puntilla de Huincán blocks, Mendoza

Abstract

The easternmost sector of the Malargüe fold and thrustbelt, between 70° and 69°40'W, in southern Mendoza Province at the Puntilla deHuincán area, is characterized by the development of thick-skinned structures.Three main thrusts are defining the orogenic front. The westernmost thrust hasa distinctive east-vergence in contraposition to the other two backthrusts. Thesecondary structures are thin-skinned thrusts, with decollements located at themiddle Cretaceous Huitrín Formation. These structures are modified at surfaceby the emplacement of the Miocene Molle Formation intrusives. The Andean upliftat the orogenic front in these latitudes was mainly Late Miocene, and wascoetaneous to the emplacement of a volcanic arc between 19 and 17 Ma in thearea, expansion generated by the shallowing of the subducted plate. However, thePuntilla de Huincán constitutes an older late Cretaceous structure associatedwith synorogenic sedimentation.