Abstract

CISNEROS, Héctor; COSTA, Carlos H.  and  GARDINI, Carlos. Neotectonic analysis of  the Cerro Salinas area, Sarmiento department, province of  San Juan. Rev. Asoc. Geol. Argent. [online]. 2010, vol.67, n.4, pp.439-449. ISSN 0004-4822.

The so called Cerro Salinas is one of  the southernmost expressions of  the Sierras Pampeanas crystalline basement. Several fault traces with N-S-trending rectilinear scarps have been recognized at its surroundings, affecting Tertiary and Quaternary deposits. The attitude of  the neotectonic  faults emplaced at  the hanging-walls controlled by bedding and  the main  lithologic contacts of   the Tertiary units, which in turn has been interpreted as a result of  flexural-slip folding related to the Andean shortening. This situation is quite similar to the neotectonic style of  the Eastern Precordillera. According to space distribution and geometries attributes of the neotectonic deformation, the analyzed area was divided into three main sections. The main neotectonic structure (Cerro Salinas fault) is the west-bounding structure of  the pre-Quaternary deposits with a recognized outcropping length of  15,77 km. Field data suggest  that main deformation  is  related  to  reverse-propagating  faults. Chronological discrimination among Quaternary morphostratigraphic  units was  based  upon multiparameter  data  and  the  signature  of   the  alluvial  surfaces  on Landsat ETM+ and ASTER images, through the principal components method. Considering the cumulative displacement of the surveyed scarps, an uplift rate of  0.13 mm/yr has been estimated for the Late Pleistocene.

Keywords : Neotectonic; Cerro Salinas; Andean deformation; Quaternary.

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