A new gravity map of southern Chile

Abstract

New onshore gravity data have been collected in Southern Chile in the region onshore of the Chile Margin Triple Junction. The aim of the project was to investigate the effects of ridge subduction on the continental margin. The resultant Bouguer anomaly map shows a regional decrease in Bouguer anomaly to the east, corresponding with thickening of the mantle wedge, a large circular low of about -60 mGal in the Bouguer Anomaly in the vicinity of Lago General Carrera and a linear trend at the western edge of the main Andean Chain along the Liquiñe -Ofqui Fault. Euler deconvolution has been used to determine the depth to the principal causative body which lies at subcrustal depths (ca. 65 km). The anomaly lies close to the predicted positions of subducted segments of the Chile Rise and the authors suggest that the anomaly is associated with the ridge subduction process.