Caracterização em multiescala de carbonatos neoproterozóicos da Pedreira GMD, Formação Lagoa do Jacaré, Grupo Bambuí, Paraopeba-MG

Abstract

The Multiscale Reservoir Characterization (Caracterização Multiescalar de Reservatórios - CAMURES) method has been proving itself an important tool of geological investigation and helping in characterizing many types of outcrops and sedi-mentary successions. The objective of the present article is to apply this method in a limestone outcrop of Lagoa do JacaréFormation, Bambuí Group, in a disabled quarry, in Paraopeba region, Minas Gerais State. For this purpose, different inves-tigative tools were used, with different scales of observation, to best describe this geological unit. A detailed lithofaciologi-cal analysis was made, and five individual lithofacies were defined. Ground Penetrating Radar and gamma-ray data were acquired to complement the knowledge about geometry and lithotypes in the study area, and reveal information concerning the lateral correlation between the geological profiles described. Microscopic petrography revealed the presence of six microfacies associations. Analysis of lithofacies and structures points to deposition under the influence of storm waves in several storm cycles on shallow-marine carbonate platform. This sequence is defined by intraclastic breccias on the bottom, that represent high energy moments, passing to lower wave-influenced energy moments, which favour deposition of fine carbonates with hummocky and planar stratification, and also ripple marks, until rare moments of calm sea with deposition of fine carbonate in the shoreface-offshore transition.