Structural architecture of the Lavrinha, Nosde and Japonês deposits, Alto Guaporé Gold Province, Amazon Craton, Brazil: insights from fold interference pattern 3D modelling and ore body geometry

Abstract

The Alto Guaporé Gold Province comprises deposits in the Meso-Neoproterozoic Aguapeí Belt, southwest Amazon Craton. The Lavrinha, Nosde, and Japonês deposits are in the hinge region of the Cágado anticline, hosted by siliciclastic metasediments. This work aims to define the structural controls of these mines, integrating 3D rendering and interpolating structural and assay data. A D1 phase was defined with two progressive stages. The D1' ductile stage includes the S₀//S₁' schistosity, spaced cleavages, S-verging folds, and Type 3 refolding. The D1'' ductile-brittle stage comprises a dome and basin refolding formed by non-coaxial shortening directions. The D2 brittle phase occurs as fracture jogs. High gold grades are related to domes and anticline regions in the muscovite schist. NW-SE ore shoots are associated with crosscutting quartz veins in the upper metasandstone. The structural setting is related to the sinistral strike-slip motion of the Amazon Craton against Laurentia during the agglutination of Rodinia. The non-coaxial deformation character derives from the asymmetry of the orogen, with the irregular block margins leading to the closure of the Aguapeí aulacogen from south to north. This work contributes to the understanding of complex ore body geometries and highlights the potential of combining geological mapping and implicit modeling.