Provenance and tectonic setting of the Neoproterozoic clastic rocks hosting the Banana Zone Cu-Ag mineralisation, northwest Botswana

Kelepile, Tebogo; Betsi, Thierry Bineli; Franchi, Fulvio; Shemang, Elisha; Suh, Cheo Emmanuel

doi:10.1016/j.jafrearsci.2017.02.018

Cited by 4 publications

(3 citation statements)

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“…The Cu‐Ag deposits of the GCZ have been described as structurally controlled, stratabound deposits by numerous researchers (e.g., Schwartz et al, 1996; Gorman, 2013; Shephard, 2014; Walsh, 2014; Lehmann et al, 2015; Kelepile et al, 2017, 2020; Hall et al, 2018; Hall et al, 2021). In addition to the Cu‐Ag deposits of the KCB (Kampunzu et al, 1998; Sillitoe et al, 2010), Piestrýnski et al .…”

Section: Geologic Settingmentioning

confidence: 99%

“…The Cu-Ag deposits of the GCZ have been described as structurally controlled, stratabound deposits by numerous researchers (e.g., Schwartz et al, 1996;Gorman, 2013;Shephard, 2014;Walsh, 2014;Lehmann et al, 2015;Kelepile et al, 2017Kelepile et al, , 2020Hall et al, 2021). In addition to the Cu-Ag deposits of the KCB (Kampunzu et al, 1998;Sillitoe et al, 2010), Piestrýnski et al (2015) identified the potential of the Neoproterozoic Ghanzi Group of the GCZ for hosting precious metals, in form of platinum group minerals (PGMs) mineralization.…”

Section: Copper-silver Deposits Of the Khoemacau Districtmentioning

confidence: 99%

“…Recent advances in understanding the geology and origin of Cu‐Ag mineralization in the KCB is a result of in‐depth studies on subjects spanning regional‐ to deposit‐scale characterization and delineation of the KCB (e.g., Schwartz et al, 1995; Gorman, 2013; Morgan, 2013; Shephard, 2014; Lehmann et al, 2015; Hall et al, 2018), depositional environment, geochronology (e.g., Modie, 1996, 2000; Hall, Hitzman, et al, 2018; Hall et al, 2021) and provenance and distribution of metals (e.g., Schwartz et al, 1995; Modie, 1996, 2000; Kelepile et al, 2017, 2020; Hall, Hitzman, et al, 2018). These studies altogether suggest that the litho‐structural control, permeability, metal source, sulfur source, and a reductant (in‐situ or mobile) were key elements for precipitation of the Cu‐Ag ores.…”

Section: Introductionmentioning

confidence: 99%

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Diagenetic and epigenetic origins for Cu‐Ag mineralization in the Khoemacau Zone 5 deposit, Kalahari Copperbelt, northwestern Botswana

et al. 2022

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In the Kalahari Copperbelt, the mechanism of regional scale Cu-Ag mineralization has remained intensely debated between early diagenesis and a single pass during a regional deformation event. At the Zone 5 Cu-Ag deposit in northwestern Botswana, the orebody is hosted preferentially by chemically reduced metasedimentary rocks that overly oxidized, hematite-bearing arkosic sandstone. An early diagenetic mineralizing event has been identified which is characterized by fine-grained stratiform pyrite, including recrystallized framboidal pyrite, intergrown with diagenetic mineral assemblages in the host-rock. Diagenetic pyrite is in textural equilibrium with chalcopyrite, sphalerite, galena, and (Fe-Co-Ni) sulfarsenide. These minerals were subsequently overprinted by a more intense, multi-stage, structurally-controlled hydrothermal Cu-Ag mineralization event related to the Damaran orogeny ($600-480 Ma). The hydrothermal Cu-Ag mineralization was deposited from hot ($236-265 C), high salinity (19-24.6 wt% NaCl equiv.) hydrothermal ore fluids. Petrographic results reveal an apparent overlap in trace metal associations (Cu, Fe, As, Zn, Pb, Ni, Co) between the two mineralizing events, which can be explained by remobilization of precursor sulfides. The major Ag-carriers in the ore are chalcocite, covellite, and bornite. The δ 34 S values of diagenetic pyrite range from À35.8 to +11.4‰, whereas those of hydrothermal epigenetic sulfides, including pyrite, range from À28.0 to +3.0‰. We propose that the hydrothermal sulfides had acquired some bacterially-reduced sulfur from earlier-formed minerals. The δ 18 O and δ 13 C values of quartz and calcite associated with the hydrothermal mineralization are typical of Neoproterozoic sediment-hosted Cu-Ag deposits. However, the δ 18 O isotopic values of the calcite gangue are anomalously depleted, which is likely due to recrystallization under metamorphic conditions. Our studies at Zone 5 indicate that the Zone 5 Cu-Ag deposit is the result of a multi-stage mineralization history that includes both diagenetic and epigenetic events (punctuated by >400 m.y.) facilitated by a strong litho-structural control.

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