Magnetotelluric prospection for exploration of folded belt areas - northwest basinThe study area is located in the northeast of the province of Salta, near the Aguas Blancas town. The structural complexity, typical of areas of folded belt, makes it difficult to obtain an adequate seismic image, which leads to other geophysical methods becoming important. Therefore, a profile of magnetotelluric (MT) stations was acquired, with the purpose of complementing the preexisting information, and evaluating the performance of the method as a technique for prospecting hydrocarbons in complex zones that are at the same time environmentally and logistically sensitive. 30 linearly arranged stations, spaced 500 m, were used. The location of the profile was chosen in such a way that it passes through an available well. In each station the time fluctuations of the components of the total surface electromagnetic fields (Ex, Ey, Hx, Hy and Hz) during a minimum of 18 hours in a frequency range of 10 KHz to 0.001 Hz were measured. Interpretative parameters and pseudosections of apparent resistivity and phase characteristic of the method were analyzed. This helped to understand the shapes of the structures, and later the 2D resistivity profile of the subsurface was obtained. The analysis of these data, integrated with the information of resistivity logs measured in wells and lithological description, gravimetry, seismic and structural models has allowed the construction of a reliable 2D geophysical model of the internal structure of the area.