ERT imaging of a shallow basin: eastern Lago Fagnano, Tierra del Fuego, Argentina

Two ERT (Electrical Resistivity Tomography) profiles were conducted at the eastern head of Lago Fagnano within the main deformation zone of the Magallanes-Fagnano Transform fault system (MFS) which represents the onland boundary between the South America and Scotia plates. Results from the inversion models have provided new evidence of the presence and location, at shallow depths, of some strands of the MFS. Tomographic models showed significant resistivity contrasts across the inferred fault zones in the subsurface. The combination of ERT, geomorphic and outcrop structural data allowed us to interpret the stepped, southward subsidence of Tertiary and Quaternary units within the studied area. The Holocene development and evolution of a shallow deltaic basin at the mouth of R�o Turbio, the eastern tributary of Lago Fagnano, was also interpreted from electrical imaging.