Gephysical Characterization of the Araguainha impact structure, MT/GO. / Caracterização geofísica da estrutura de impacto de Araguainha, MT/GO

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Araguainha is the largest and the best-exposed complex crater of South America, formed in horizontal sediments of the Paraná Basin. Its portentous structure with 40 km in diameter and 25 km of transient cavity reveals a negative contrast of density and magnetic susceptibility in the central uplift. That feature allows to infer a limit of physical property between the uplifted central core and the uplifted granite basement, which shows a low Konigsberger?s ratio. The geophysical characterization of Araguainha is sustained by 2,5D modeling with gravity, aeromagnetic, and ground magnetic information and It allows to classify it as a concentric, symmetrical structure, with average basement depth of 1.0 km, except in the southern rim, that shows a bigger uplift. The basement/sediment interface is cut by specular pairs of radial faults that appears in the modification stage of the crater. These brittle structures are responsible for the biggest depths in the annular basin region, and they promote a sediment constriction with horizontal radial tension. The observation and interpretation of these deformations allow to characterize Araguainha as an impact brittle-ductile domain structure.

ASSUNTO(S)

magnetometria modelagem geofísica profundidade do embasamento gravity cratera crater geophysical modeling magnetometry gravimetria

ACESSO AO ARTIGO

Documentos Relacionados