Structural controls of fluid flow and gold mineralization in the easternmost parts of the Karagwe-Ankole Belt of north-western Tanzania

Koegelenberg, C.; Kisters, Alexander F. M.; Harris, Chris

doi:10.1016/j.oregeorev.2016.03.010

Cited by 14 publications

(4 citation statements)

References 35 publications

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“…Gold mineralization has been linked to several deformation events, i.e. during the early Mesoproterozoic (Koegelenberg et al, 2016), the early Neoproterozoic (Brinckmann et al, 2001;Pohl et al, 2013), the late Pan-African at ~530 Ma (Brinckmann et al, 2001;Walemba et al, 2004;Fernandez-Alonso et al, 2012), and even a link was made with the recent development of the Western rift. The findings of this study on the Imonga-Saramabila samples are in agreement with the findings of Dewaele et al (2015) and of Wouters et al (2020), providing additional evidence for the model proposed with orogenic gold formation related to the early-Neoproterozoic deformation.…”

Section: Gold Metallogenesis In the Kabmentioning

confidence: 99%

“…Gold mineralization has been linked to one or more of the several deformation events. The mineralization has been given an Early Mesoproterozoic age (Koegelenberg et al, 2016), an early Neoproterozoic age (Brinckmann et al, 2001;Pohl et al, 2013) related to the main Kibaran deformation event, and a Pan-African age of ~530 Ma (Brinckmann et al, 2001;Walemba et al, 2004;Fernandez-Alonso et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Current state of knowledge of the gold mineralization at Imonga-Saramabila, Maniema (DR Congo): a petrographic and mineralogical study of the mineralized vein system

DE GROOTE,

COOLS,

WOUTERS

et al. 2023

Geol. Belg.

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The Great Lakes area in Central Africa forms a large metallogenic province that hosts important deposits of gold mineralization. We present a petrographic, mineralogical and geochemical study of unique borehole samples from the Imonga-Saramabila gold deposit, a historical mine site located in the Maniema Province (DR Congo) in the Karagwe-Ankole belt (KAB) in the Great Lakes area and one of the only places in the Maniema province with accessible boreholes allowing to study the mineralization. The samples are metasedimentary rocks belonging to the Mesoproterozoic Kivu Supergroup, with bedding-parallel meta-igneous rocks. These rocks have undergone upper greenschist to lower amphibolite facies metamorphism, based on the presence of andalusite and chiastolite porphyroblasts, and are affected by hydrothermal alteration. The porphyroblasts formed during peak metamorphism and posterior to a first vein generation. Three additional vein generations were identified at Imonga based on crosscutting relationships, with the second and third events overprinting the porphyroblasts by intense chloritization, and associated with sulfide mineralization. The fourth vein generation is again barren. The first veining event formed pre-folding and the three subsequent generations postdate folding, as concluded based on the relationship of the veins with the cleavage. Only one important folding event is proposed based on the development of only one cleavage. Gold occurs as free gold or is included in pyrite in the second (and maybe third) vein generation. Based on the paragenesis, structural characteristics, and the link between veining and metamorphic minerals, the gold mineralization at Imonga is interpreted to be linked to the early Neoproterozoic (~980 Ma) compressional deformation event, associated with the amalgamation of the Rodinia supercontinent.

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Section: Gold Metallogenesis In the Kabmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Current state of knowledge of the gold mineralization at Imonga-Saramabila, Maniema (DR Congo): a petrographic and mineralogical study of the mineralized vein system

DE GROOTE,

COOLS,

WOUTERS

et al. 2023

Geol. Belg.

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“…The model spatial features are commonly selected as critical predictive variables for 3D MPM, which has already contributed to new resource discoveries [12,14,[26][27][28][29][30]. Notably, mineral deposit formation involves complicated geodynamic processes in both space and time, in which magma and/or fluid flow, and its evolution and interaction with wall rocks, dominate the mineralization distribution [31][32][33][34][35]. While the spatial controls on mineralization are vital for exploration, the weak or insufficient representation of metallogenic geodynamic processes (e.g., volumetric strain, temperature variation) may reduce the reliability, accuracy, and confidence of prediction.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Mineral Prospectivity Modeling with the Integration of Ore-Forming Computational Simulation in the Xiadian Gold Deposit, Eastern China

Liu,

Guo,

Wang

et al. 2023

Applied Sciences

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Finding new, effective predictive variables for 3D mineral prospectivity modeling is both important and challenging. The 3D ore-forming numerical modeling quantitively characterizes the complex coupling-mineralization process of the structure, fluid, heat, and wall rock, which may be potential indicators for mineral exploration. We here conducted 3D mineral prospectivity modeling with the integration of ore-forming computational simulation information in the Xiadian orogenic gold deposit, China, to examine whether the simulation data input can improve the reliability of prospectivity modeling. First, we constructed the 3D models of the orebody and fault to extract the fault geometric features using spatial analysis, as they are always considered to be the crucial controls of gold distribution. Second, we performed 3D numerical modeling of the deformation–fluid–heat-coupling process of the structurally controlled hydrothermal Au system using the FLAC3D platform. Finally, the fault-geometry features (buffer, dip, dip variation, and undulation) and the ore-formation-simulation indices (volume strain, shear strain, temperature variation, and fluid flux) were integrated using Bayesian decomposition modeling, which has a promising nonlinear model ability and a flexible variable-integration ability. The prospectivity modeling results demonstrated that the model generated by combining geometry and simulation variables achieved significantly higher AUC, precision, accuracy, Kappa, and F1 scores compared to other models using a single-predictor-variable dataset. This suggests that the joint use of geometry and simulation variables construct a comprehensive association between gold and its ore-controlling factors, thereby resulting in a highly reliable prospectivity model. Thus, the approach of 3D mineral prospectivity modeling aided by ore-forming numerical simulation proves to be more useful in guiding mineral exploration, especially in the condition of fewer variables. Based on the prospectivity modeling outcomes, we identified four gold targets at depth in the Xiadian district that warrant focused exploration efforts.

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“…Physical model experiments and numerical simulation on water-rock geochemical interaction are powerful tools for investigating underground fluid flow in fault and fracture systems and exploring the mechanisms of hydrothermal fluid mineralization and dissolution, which can be induced by earthquakes, volcanism, deformation, and sediment remobilization [13,[16][17][18][19]. As one of the pioneer studies, Ramsay [20] discovered that the crystals making up the extension vein filling in many naturally deformed crustal rocks often show a fibrous structure and seem to be built up by a succession of "crack-seal" increments: the elastically deforming rock fails by fractures, and the walls of the open micro-crack are sealed together by crystalline material derived by pressure solution in the rock matrix.…”

Section: Introductionmentioning

confidence: 99%

Mineral Filling Pattern in Complex Fracture System of Carbonate Reservoirs: Implications from Geochemical Modeling of Water-Rock Interaction

Zhang

Luo

et al. 2019

Geofluids

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Much research has been conducted on physical and numerical modeling that focus on stress state and structural controls on subsurface geofluid flow, yet very few attempts have been made to discover and quantify the mineral precipitation/dissolution kinetics in complex fracture system such as Tarim Basin of China. We conducted a geochemical simulation study using the outcrop fracture networks in Ordovician carbonate rocks in Tabei Outcrop Area of Tarim Basin. Structural analysis, filling analysis within the fracture networks and surrounding rocks were used to constrain the generation and geochemical evolution of the geofluids. Using an advanced reactive transport simulation platform TOUGHREACT, a pertinent thermodynamic system was applied to establish the geological model of the fracture-surrounding rock, where the corresponding calcium carbonate (CaCO3) solution was configured to replace the deep saturated hydrothermal fluids. Different types of mineral parameters were considered with material balance and phase equilibrium calculation to perform numerical simulation of multi-field, e.g., pressure field, temperature field, seepage field and chemical field under formation conditions. The simulation results were consistent with field observations. The major findings of this simulation study include: (1) Along with fluid injection, local dissolution occurred within the fractures and matrix, but with the gradual saturation of calcium ions and the increasing pH value, considerable calcite precipitation occurred. (2) The dissolution/precipitation in different fractures was mainly affected by their structure and physical properties, resulting in changes in fluid flow rate, temperature, pressure and ion concentration over time. (3) In the same group, the degree of mineral filling of small-aperture fractures, low-angle fractures and shallow fractures was significantly higher than other types of fractures. (4) The better the connectivity between reticular fractures and the higher the linear density of fractures, the lower the mineral filling degree. (5) Dissolution phenomenon strengthened within large-aperture conjugated fractures gradually along the flow direction. The proposed methodologies in this study can be applied to model effective fracture filling of other deep reservoirs.

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Structural controls of fluid flow and gold mineralization in the easternmost parts of the Karagwe-Ankole Belt of north-western Tanzania

Cited by 14 publications

References 35 publications

Current state of knowledge of the gold mineralization at Imonga-Saramabila, Maniema (DR Congo): a petrographic and mineralogical study of the mineralized vein system

Current state of knowledge of the gold mineralization at Imonga-Saramabila, Maniema (DR Congo): a petrographic and mineralogical study of the mineralized vein system

Three-Dimensional Mineral Prospectivity Modeling with the Integration of Ore-Forming Computational Simulation in the Xiadian Gold Deposit, Eastern China

Mineral Filling Pattern in Complex Fracture System of Carbonate Reservoirs: Implications from Geochemical Modeling of Water-Rock Interaction

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