MODELAGEM E INVERSÃO 2D DE DADOS MAGNETOMÉTRICOS APLICADOS NA CARACTERIZAÇÃO DA GEOMETRIA DO SINCLINAL GANDARELA E HOMOCLINAL CURRAL QUADRILÁTERO FERRÍFERO, MG

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The aim of the present study is the geometrical characterization of Gandarela syncline and Curral homocline, the major structures in the Quadrilátero Ferrífero, based on an integrated analysis of geophysical data. The Gandarela syncline is a reclined fold with NE-SW trending axial trace and hinge zone plunging to southeastern. The Curral homocline is represented by inverted limb of alloctonous north vergent recumbent fold named Curral nappe. Several high angle faults cuts the Curral homocline. The geophysical database used includes (i) aeromagnetic data from the Brasil-Alemanha geophysical project, (ii) magnetic land survey carried out in the regions of interest and (iii) regional gravity data arising of combination of continental gravity data, ship borne gravity data and satellite altimeter data and geological data available in the literature, as well as geological data obtained during the magnetic land survey. Integration of geological and geophysical data constitutes the applied methodology, using tools that aid in the identification and in the adjustment of depth of magnetic sources. 2D Euler deconvolution technique estimates the depths of the tops of the magnetic sources and/or magnetic bodies. 2D magnetic_gravity method modeling allows to adjust the observed anomalies (magnetic_gravity) and calculated anomalies by changing of shape of the irregular bodies. The inversion of magnetic anomalies consists in mathematical operation of the magnetic data for the generation of geophysical models close to geological/structural models by entrance of the free and fixed parameters. In 2D linear inversion admit the distribution of magnetic susceptibility as free parameter and the geometry as fixed. Thus in the 2D nonlinear inversion, the fixed parameter is the magnetic susceptibility and the geometry as free. The results of the present study characterize the structural geometry of the Gandarela syncline and Curral homocline based on the interpretation of the geological/geophysical integrated data. The geometry of the Gandarela syncline is thinning in depth, according to the proposed model in the geological literature. The Curral homocline was divided in two sectors (West Curral area and East Curral area). The geometry of East Curral area indicated the presence of an intrusive body, whose geometry had not still been inferred in depth, corresponding probably in surface, with the General Carneiro granite. The West Curral area present the basement-involved recumbent fold geometry.

ASSUNTO(S)

geologia modelagem geofísica quadrilátero ferrífero (mg) sinclinal gandarela (mg) rochas curral, serra do (mg)

ACESSO AO ARTIGO

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