Geological mapping in the Argentine Frontal Cordillera (~30°30’ S) using ASTER images

Abstract

The eastern flank of the Argentine Frontal Cordillera at ~30°30’ S is a remote area with rugged topography and high elevations that hinder geological field mapping. This task is also challenging because several outcrops are dominated by Permian-Triassic and Cenozoic volcanic rocks of intermediate to acid compositions with scarce geochronological age constraints. In this work, we use ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) data to clarify the structural and stratigraphic framework of the region. Visible and near infrared (VNIR) and shortwave infrared (SWIR) band combinations, integrated with field observations, are effective in identifying first-order geological features. In addition, the Semi-Automatic Classification Plugin (SCP; a free open-source plugin for QGIS) is capable of discriminating lithological units and is especially useful to visualize their distribution. Results presented here allow us to characterize Permian-Triassic and Cenozoic units, propose tentative correlations between the Permian-Triassic rocks, and outline major tectonic structures in the study area. This work demonstrates the capability of ASTER data to improve geological mapping, especially in those places where field work is difficult.