The Andean orogenic front at Sierra de Las Peٌas-Las Higueras, Mendoza, Argentina

The Sierra de Las Peñas-Las Higueras (Mendoza Province, Argentina, 32°15′S–32°45′S) presents one of the clearest and most continuous exposures of the Quaternary thrust front of the Precordilleran fold-and-thrust belt. It is characterized by an east-verging thrust that breaks the surface and causes Neogene sedimentary rocks to override Quaternary alluvial conglomerates. Monoclinal folds and progressive unconformities are characteristic of deformation in the upper part of the alluvial cover, indicating synchronous development of sedimentation and thrusting during the Quaternary. South of this range, ongoing deformation is by gentle warping of the piedmont alluvial plain, hiding blind thrusts at depth.