Gold Potentials Estimation using 3D Restoration Modeling – Mount Pleasant Area, Western Australia

Pablo Mejia-Herrera and Jean-Jacques Royer and Maria Kakurina. ( 2015 )
in: Proceedings of the 13th Biennial SGA Meeting, pages 1739-1742, SGA

Abstract

Gold deposits are used to be related to fault systems that control metals’ transport and accumulation through relatively high permeable discontinuous structures. However, some coeval gold deposits occur at locations far from the main faults. In those cases, fractures appear due to the rock mass heterogeneity. This work may explain the presence of such gold accumulations in Mount Pleasant region, Western Australia, by applying restoration tools to estimate strains during the stretching tectonic phase. Firstly, a 3D Gocad/Skua solid-model was built by using available geological maps and cross-sections. The backward model was obtained by flattening a stretching-representative reference surface selected from the litho-time scale sequence. The present 3D model was restored regionally assuming a flexural slip deformation style and using a full geomechanical finite-element-based approach. Rock heterogeneities drive damages in locations far from the fault systems. The off-fault damage areas which follow the regional deformation trend are located preferentially in lithological contacts. Based on a logistic regression method, it is shown that high gold occurrences off-fault zones coincide spatially with locally-high-gradients of the first deformational parameter calculated on the restored strain tensor. This methodology could be used for inferring favorable areas in green exploration fields.

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    BibTeX Reference

    @INPROCEEDINGS{Mejia:2015a,
        author = { Mejia-Herrera, Pablo and Royer, Jean-Jacques and Kakurina, Maria },
        editor = { SGA },
         title = { Gold Potentials Estimation using 3D Restoration Modeling – Mount Pleasant Area, Western Australia },
         month = { "aug" },
     booktitle = { Proceedings of the 13th Biennial SGA Meeting },
        series = { Symposium B },
        volume = { 5 },
          year = { 2015 },
         pages = { 1739-1742 },
     publisher = { SGA },
      abstract = { Gold deposits are used to be related to fault systems that control metals’ transport and accumulation through relatively high permeable discontinuous structures. However, some coeval gold deposits occur at locations far
    from the main faults. In those cases, fractures appear due to the rock mass heterogeneity. This work may explain the presence of such gold accumulations in Mount Pleasant region, Western Australia, by applying restoration tools to estimate strains during the stretching tectonic phase. Firstly, a 3D Gocad/Skua solid-model was built by using available geological maps and cross-sections. The backward model was obtained by flattening a stretching-representative reference surface selected from the litho-time scale sequence. The present 3D model was restored regionally assuming a flexural slip deformation style and using a full geomechanical finite-element-based approach. Rock heterogeneities drive damages in locations far from the fault systems. The off-fault damage areas which follow the regional deformation trend are located preferentially in lithological contacts. Based on a logistic regression method, it is shown that high gold occurrences off-fault zones coincide spatially with locally-high-gradients of the first deformational parameter calculated on the restored strain tensor. This methodology could be used for inferring favorable areas in green exploration fields. }
    }