A new gravity map of southern Chile and its preliminary interpretation

New onshore gravity data have been collected in Southern Chile in the regio n onshore of the Chile Margin Triple Junction. The aim of the project was t o investigate the effects of ridge subduction on the continental margin. Th e resultant Bouguer anomaly map shows a regional decrease in Bouguer anomal y to the east, corresponding with thickening of the mantle wedge, a large c ircular low of about -60 mGal in the Bouguer Anomaly in the vicinity of Lag o General Carrera and a linear trend at the western edge of the main Andean Chain along the Liquine -Ofqui Fault. Euler deconvolution has been used to determine the depth to the principal causative body which lies at subcrust al 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 anom aly is associated with the ridge subduction process.