Implicit geological modelling of key platiniferous reefs of the main chamber of the Bushveld complex : implications for the complexs structural history

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Stellenbosch : Stellenbosch University
ENGLISH ABSTRACT: The Bushveld Complex (BC) is the world’s largest source of platinum group metals and has been extensively studied for decades. The focus of these studies has typically been its geochemistry, magma and PGM genesis, mineral characterization and intrusion mechanisms. Relatively little work been undertaken on the overall 3D geometry of the complex. Without adequate contextualization, analytical results and interpretations from the aforementioned studies may not fully represent the areas within which they were completed, or more subtle trends may not be evident from 2D generic or 3D schematic models. This study aims to offer a broader framework within which these more focused studies may be better contextualized, providing a geological and contextual backdrop to these studies and ongoing research. This thesis details the construction of 3D implicitly-modelled Merensky and UG2 Reefs across the Rustenburg Layered Series (RLS) of the BC, using open-source and public-domain data. Implicit modelling refers to the mathematical generation of surfaces or solids in 3D space, conditioned to real world data. Multiple data sources, modelling workflows and solutions were explored, to account for the disparities in data resolution, data spacing/clustering, model scale and model output. Modelled features were scrutinised, and anomalous trends or features were identified and subsequently linked to previously-observed or -mapped features. Key outcomes are (1) Construction of a representative, fully implicit, dynamic geological model of the Merensky and UG2 Reefs over the Rustenburg Layered Series of the BC. This bodes well for similar “proof-of-concept” studies over similarly large volumes; (2) Identification of modelled features that may add to the current understanding of the BC’s kinematic history and cumulative deformation; and (3) Identification and analysis of subtle geometrical trends and patterns (such as inter-reef spacing and modelled depths), as well as identification of structural domains, which may not have been apparent from numerous, more focussed or isolated petrological/geochemical studies, in model outputs.
Thesis (MSc)--Stellenbosch University, 2020.
Geological modeling, 3-D geomodelling, Geometry, Geology -- South Africa -- Bushveld Complex, Mining geology, Bushveld Complex (South Africa) -- Structural history, Platinum mines and mining, UG2 Reefs, UCTD