Late Cenozoic stratigraphy and structure of the Varela block, southern San Luis province, Argentina

Abstract

Neogene sedimentary deposits cover approximately 10,000 km2 in the southern sector of San Luis province, in the central-western region of Argentina. These sediments mainly consist of sandy loessoid continental deposits and are buried and masked by late Quaternary sand sheets and dune fields. The stratigraphic correlation of the identified units has been hindered by limited outcrops, thin thickness, and scarcity of chronological information. Recent studies in the southernmost region of the Sierra de San Luis have established regional correlation schemes of the stratigraphic units and linked the sedimentary accumulations with Andean diastrophism. The Neogene sediments in the southern foothills of the Sierras Pampeanas in San Luis form part of a meridional elevation characterized by rocky outcrops. The analysis of its stratigraphic and structural characteristics is significant to understand the tectonic dynamics of this sector. The aim of this work is to analyze the Neogene stratigraphic succession and the structure of the Varela block in order to establish the tectonic framework of its deposition and deformation. An analysis of patterns in the drainage network and seismicity was also conducted to determine neotectonic activity in the area.