Structural features of the southern Tulum Fault System, western central Argentina, through gravimetric data and geomorphologic analyses

Abstract

A gravimetric analysis over the Tulum Valley was made. This data was used to reveal the structuralsetting of the Tulum Fault System situated in the southeastern part of San Juan province in the aridwestern part of Argentina. This system is the boundary between two geological provinces, the easternPrecordillera Oriental and the Sierras Pampeanas Occidentales. Gravity data was processed using upwardcontinuation and vertical derivative filters and all the results were compared with the geomorphologicaland the drainage systems maps of the area. Our assessment confirms the presence of two structures inthe Pampeano basement with positive anomalies similar to those found in Valdivia and Barboza hills,two important depocenters with low gravimetric gradients separated by a zone with higher gravityanomalies than the depocenters to the east and west. In view of this, a structural map is proposed for thearea. This system is important not only because it is the boundary between two geological provinces andhas significance regarding regional tectonic issues but also because it controls the surface drainage, soilsdistribution and groundwater flow of the Tulum basin conditioning the land use distribution.