Estrutura geoelétrica da Bacia do Iguatu, Ceará, Brasil

A set of forty five broadband (001-1000sec) magnetotelluric (MT) soundings have been made along two profiles (SW-NE) and (NW-SE ) crossing the Iguatu Basin, Ceará, Brazil, a Brazilian intra cratonic basin. The shape of the basin is almost elliptic and these two profiles correspond to the two semi axes. The static shift galvanic effects which distorts the TE mode of MT data were removed using time domain transient electromagnetic measurements (TDEM) at each sounding station. 2-D inversions of MT profiles gives an estimate of the geoelectric structure in subsurface. In the SW-NE profile, the depth of basement reaches a maximum of about 1800 m with a depocenter displaced in the NE direction. In the NW-SE profile, almost perpendicular to the regional geological trend, the maximum depth is about 1200 m. These depths and shapes are compared with 3-D inversion gravity models.