Subsurface architecture of aeolian erosion features in hyper-arid alluvial systems of the Atacama Desert: Insights from ground-penetrating radar

Aeolian erosion of the alluvial deposits in the hyper-arid core of the Atacama Desert appears in several sites in the form of deflation hollows. Despite constituting signs of degradation of the unique and ancient landscape, their architecture and formation is as yet poorly understood. Ground-penetrating radar (GPR) is an effective way to image the internal structure of such aeolian landforms, and in this study, eight 200-500 m GPR profiles were acquired across deflation hollows and an eroded alluvial fan. A 400 MHz antenna was used, penetrating more than 3 m deep. Evaporitic crusts and salt-cemented layers were identified and mapped. In the leeward side of hollows, younger aeolian deposits can be differentiated from the older alluvial sediments, and similarities were found in the radar facies of several eroded surfaces. This work reveals the shallow subsurface architecture of the aeolian cover and alluvial deposits and provides new insights into the landscape formation in hyper-arid environments through the use of GPR.