Aplicação do método magnetotelúrico nas Bacias do Solimões e Amazonas

Abstract

The present repor! is a review on Solimões and Amazonas basins geology, and magnetotelluric method application to Juruá region. The report results were obtained from J. L. Porsani's Thesis which is the main public reference on magnetotelluric use in Solimões basin. The magnetotelluric data acquisition and processing have permitted to detail the structural geology of that region through images of geo-electric sections. The field data were collected along three profiles of 15 km long, the spaces between each 35 stations ranging from 400 m to 3500 m. The frequency range was 0.001 Hz to 300 Hz which allow investigating depths down to 60 km. The static effect was corrected. The Juruá sedimentary package is a sub-horizontal layer sequence which turns possible a one dimensional modeling. The invariant of the magnetotelluric tensor was utilized for analyzing the geo-electric subswface. ln arder to inverting the tensor the Bostick-Niblett transformation and one-dimension Occam inversion algorithm were performed to. ln the Solimões basin it is identified a sedimentary package corresponding to a depositional sequence which layers are conductive or resistive altematively, a fault zone and the geo-electric basement. The results show a good agreement with seismic data acquisition and resistivity well logs.