Abstract
This paper presents mineral prospectivity mapping to identify potential new exploration ground for polymetallic Sn–F–REE mineralization associated with the Bushveld granites of the Bushveld Igneous Complex, South Africa. The Lebowa Granite Suite, commonly known as the Bushveld granites, is host to a continuum of polymetallic mineralization with a wide range of metal assemblages (Sn–Mo–W–Cu–Pb–Zn–As–Au–Ag–Fe–F–U–REE), ranging from a high-temperature to a low-temperature magmatic hydrothermal mineralizing environment. The prospectivity map was generated by fuzzy logic modeling and a selection of targeting criteria (or spatial proxies) based on a conceptual mineral system highlighting critical processes responsible for the formation of the polymetallic mineralization. The spatial proxies include proximity to differentiated granites (as heat and metal-rich fluid sources), Rb geochemical map (fluid-focusing mechanism such as fractionation process), principal component maps (PC 4 Y–Th and PC 14 Sn–W, fluid pathways for both high- and low-temperature mineralization) and proximity to roof rocks (traps for fluids). Logarithmic functions were used to rescale rasterized evidential maps into continuous fuzzy membership scores in a range of [0, 1]. The evidential maps were combined in two-staged integration matrix using fuzzy AND, OR and gamma operators to produce the granite-related polymetallic Sn–F–(REE) prospectivity map. The conceptual mineral system model and corresponding prospectivity model developed in this study yielded an encouraging result by delineating the known mineral deposits and occurrences of Sn–F–(REE) mineralization that were not used to assign weights to the evidential maps. The prospectivity model predicted, on average, 77% of the known mineral occurrences in the BIC (i.e., 56 of 73 Sn occurrences, 12 of 15 F occurrences and 6 of 8 REE occurrences). Based on this validation, 13 new targets were outlined in this study.
Similar content being viewed by others
References
Absolom, S. (1986). The buffalo fluorspar deposit, Naboomspruit district. In C. R. Anhaeusser & S. Maske (Eds.), Mineral deposits of South Africa (Vol. II, pp. 1337–1341). Johannesburg: Geological Society of Southern Africa.
Bailie, R. H., & Robb, L. J. (2004). Polymetallic mineralization in the granites of the Bushveld Complex - examples from the central southeastern lobe. South African Journal of Geology, 107(4), 633–652.
Bonham-Carter, G. F. (1994). Geographic information systems for geoscientists: Modelling with GIS. Oxford: Pergamon.
Borrok, D. M., Kesler, S. E., Boer, R. H., & Essene, E. J. (1998). The Vergenoeg magnetite-fluorite deposit, South Africa: support for a hydrothermal model for massive iron oxide deposits. Economic Geology, 93(5), 564–586.
Carranza, E. J. M. (2008). Geochemical anomaly and mineral prospectivity mapping in GIS. Handbook of exploration and environmental geochemistry (p. 368). Amsterdam.: Elsevier.
Carranza, E. J. M., & Hale, M. (2001). Geologically-constrained fuzzy mapping of gold mineralization potential. Baguio district, Philippines, Natural Resources Research, 10, 125–136.
Cawthorn, R. G., Eales, H. V., Walraven, F., Uken, R., & Watkeys, M. K. (2006). The bushveld complex. In M. R. Johnson, C. R. Anhaeusser, & R. J. Thomas (Eds.), The geology of South Africa (pp. 261–281). Johannesburg: Council for Geoscience.
Champion, A.T. (1970). The mineralogy and related geology of the Albert Silver Mine, Bronkhorstspruit, Transvaal. Unpublished M.Sc. Thesis, University of Natal, p. 96.
Chung, C. J., & Fabbri, A. G. (1993). The representation of geoscience information for data integration. Nonrenewable Resources, 2, 122–139.
Coetzee, J.C. (1984). A geochemical and petrographical investigation of the low-grade tin deposit in the Bobbejaankop Granite at the Zaaiplaats Tin Mine. Unpublished M.Sc thesis, University of Pretoria, p. 126.
Coetzee, J. C. (1986). The Lease Granite—a granophyric, miarolitic mineralised granite at the apical region of tin-tungsten system, Transvaal. Geological Society of South Africa, 89, 335–345.
Crocker, I.T. (1976). Fluorite mineralization in the Bushveld granites southeast of Rooiberg, Transvaal. Unpubl. M. Sc thesis, Univ. Stellenbosch, pp 118.
Crocker, I. T. (1979). Metallogenic aspects of the Bushveld granites: fluorite, tin and associated rare-metal carbonate mineralisation. Spec. Publ. Geol Soc. S. Afr., 5, 275–295.
Crocker, I. T., Eales, H. V., & Ehlers, D. L. (2001). The fluorite, cassiterite and sulphide deposits associated with the acid rocks of the Bushveld complex. Memoir of the Council for Geoscience, 90, 151.
Crocker, I. T., Martini, J. E. J., & Söhnge, A. P. G. (1988). The fluorspar deposits of the Republics of South Africa and Bophuthatswana. Geological Survey of South Africa Handbook, 11, 172.
De Graaf, L. (1982). Regional geological and geochemical studies of the acid phase of the Bushveld Complex in the search for tin. Unpublished Ph.D thesis, University of Bristol, p. 306.
De Quadros, T. F. P., Koppe, J. C., Strieder, A. J., & Costa, J. F. C. L. (2006). Mineral-potential mapping: a comparison of weights-of-evidence and fuzzy methods. Natural Resources Research, 15, 49–65.
DuToit, M. C., & Pringle, I. C. (1998). Tin. In M. G. C. Wilson & C. R. Anhaeusser (Eds.), The mineral resources of South Africa (pp. 613–620). Johannesburg: Handbook of the Council for Geoscience.
Elliott, B. A., Verma, R., & Kyle, J. R. (2016). Prospectivity modeling for cambrian-ordovician hydraulic fracturing sand resources around the llano Uplift, Central Texas. Natural Resources Research, 25, 389–415.
Ford, A., Miller, J. M., & Mol, A. G. (2016). A comparative analysis of weights of evidence, evidential belief functions, and fuzzy logic for mineral potential mapping using incomplete data at the scale of investigation. Natural Resources Research, 25, 19–33.
Freeman, L.A. (1998). The nature of hydrothermal fluids associated with granite-hosted polymetallic mineralisation in the eastern lobe of the Bushveld Complex. Unpubl. PhD thesis, Univ Wits, Jhb, pp. 333
Graedel, T. E., Gunn, G., & Tercero, E. (2014). Metal resources, use and criticality. In G. Gunn (Ed.), Critical metal handbook (p. 439). Hoboken: Wiley.
Graupner, T., Mühlbachb, C., Schwarz-Schampera, U., Henjes-Kunsta, F., Melchera, F., & Terblanche, H. (2015). Mineralogy of high-field-strength elements (Y, Nb, REE) in the world-class Vergenoeg fluorite deposit, South Africa. Ore Geology Reviews, 64, 583–601.
Groves, D. I., & McCarthy, T. S. (1978). Fractional crystallisation and the origin of tin deposits in granitoids. Mineralium Deposita, 13, 11–26.
Hagemann, S. G., Lisitsin, V. A., & Huston, D. L. (2016). Mineral system analysis: Quo vadis. Ore Geology Reviews, 76, 504–522.
Hall, M., & Liebenberg, L. (2011). Mokopane Tin Project, South Africa: independent technical report. pp. 379
Hartzer, F. J. (1994). Geology of transvaal inliers in the Bushveld Complex (p. 222). Memoire: Council for Geoscience.
Hoshino, M., Watanabe, Y., Moritz, R., Ovtcharova, M., Spangenberg, J., & Putlitz., B. (2014) Magmatic, hydrothermal and weathering REE mineralization of the Blokspruit fluorite prospect, Bushveld granitic complex, South Africa. In Symposium 2: Mineralogy, Petrology, Geochemistry. Swiss Society of Mineralogy and Petrology (SSMP)
Hunt, J.P. (2005). Geological characteristics of Iron Oxide Copper Gold (IOCG) type mineralisation in the Western Bushveld Complex. Unpublished M.Sc. Thesis. University of the Witwatersrand, pp. 250
Huston, D. L., Mernagh, T. P., Hagemann, S. G., Doublier, M. P., Fiorentini, M., Champion, D. C., et al. (2016). Tectonometallogenic systems—the place of mineral systems within tectonic evolution, with an emphasis on Australian examples. Ore Geology Reviews, 76, 168–210.
Kinnaird, J.A., Kruger, F.J., & Cawthorn, R.G. (2003). An isotopic study of Fluorite related to the granites of the Bushveld Complex. Information circular no. 373, Economic Geology Research Institute Hugh Allsopp Laboratory, University of the Witwatersrand, Johannesburg, pp. 22.
Kinnaird, J. A., Kruger, F. J., & Cawthorn, R. G. (2004). Rb–Sr and Nd–Sm isotopes in fluorite related to the granites of the Bushveld Complex. South Africa Journal of Geology., 107(3), 413–430.
Kleeman, G. J., & Twist, D. (1989). The compositionally-zoned sheet-like granite pluton of the Bushveld Complex: evidence bearing on the nature of a-type magmatism. Journal of Pet, 30(6), 1383–1414.
Kreuzer, O. P., Etheridge, M. A., Guj, P., McMahon, M. E., & Holden, D. J. (2008). Linking mineral deposit models to quantitative risk analysis and decision-making in exploration. Economic Geology, 103, 829–850.
Labuschagne, L. S. (2004). Evolution of the ore–forming fluids in the Rooiberg Tin Field, South Africa. Memoir of the Council for Geoscience, South Africa, 96, 126.
Lenthall, D.H., & Hunter, D.R. (1977). The geology, petrography and geochemistry of the Bushveld granites and felsites in the Potgietersrust tin field: Inform. Circular. Econ. Geol. Research Unit. University of Witwatersrand, 110, p. 91.
Lisitsin, V. A., González-Álvarez, I., & Porwal, A. (2013). Regional prospectivity analysis for hydrothermal-remobilised nickel mineral systems in western Victoria, Australia. Ore Geology Reviews, 52, 100–112.
Lusty, P. A. J., Scheib, C., Gunn, A. G., & Walker, A. S. D. (2012). Reconnaissance-scale prospectivity analysis for gold Mineralisation in the Southern Uplands-Down-Longford Terrane, Northern Ireland. Natural Resources Research, 21, 359–382.
McCuaig, T. C., Beresford, S., & Hronsky, J. (2010). Translating the mineral systems approach into an effective exploration targeting system. Ore Geology Reviews, 38, 128–138.
McKay, G., & Harris, J. R. (2016). Comparison of the data-driven Random Forests model and a knowledge-driven method for mineral prospectivity mapping: a case study for gold deposits around the Huritz Group and Nueltin Suite, Nunavut, Canada. Natural Resources Research, 25, 125–143.
McNaughton, N. J., Pollard, P. J., Groves, D. I., & Taylor, R. G. (1993). A long-lived hydrothermal system in Bushveld granites at the Zaaiplaats tin mine; lead isotope evidence. Economic Geology, 88(1), 27–43.
Nykänen, V., Groves, D. I., Ojala, V. J., Eilu, P., & Gardoll, S. J. (2008). Reconnaissance scale conceptual fuzzy-logic prospectivity modeling for iron oxide copper e gold deposits in the northern Fennoscandian Shield, Finland. Australian Journal of Earth Sciences, 55, 25–38.
Ollila, J. T. (1984). The crystallisation of a tin-bearing granite suite. The Bushveld granites in the Zaaiplaats area, South Africa. Bullettin Geological Society, 56(1–2), 75–88.
Pirajno, F. P. (1992). Hydrothermal mineral deposits - Principles and fundamental (p. 708). Berlin.: Springer.
Pollard, P. J., Andrew, A. S., & Taylor, R. G. (1991). Fluid inclusion and stable isotope evidence for interaction between granites and magmatic hydrothermal fluids during formation of disseminated and pipe-style mineralization at the Zaaiplaats Tin Mine. Economic Geology, 86, 121–141.
Pollard, P. J., & Taylor, R. G. (1986). Progressive evolution of alteration and tin mineralisation: controls by interstitial permeability and fracture-related tapping of magmatic fluid reservoir in tin granites. Economic Geology, 81, 1795–1800.
Pollard, P. J., Taylor, R. G., & Tate, N. M. (1989). Textural evidence for quartz and feldspar dissolution as a mechanism of formation for the maggs pipe, Zaaiplaats Tin Mine, South Africa. Mineralium Diposita, 24, 210–218.
Porwal, A., Carranza, E. J. M., & Hale, M. (2003). Knowledge-driven and data-driven fuzzy models for predictive mineral potential mapping. Natural Resources Research, 12, 1–25.
Pringle, I. C. (1986). The Zwartkloof fluorite deposit, Warmbaths district. In C. R. Anhaeusser & S. Maske (Eds.), Mineral deposits of South Africa (Vol. II, pp. 1343–1349). Johannesburg: Geological Society of Southern Africa.
Reddy, R. K. T., Bonham-Carter, G. F., & Galley, A. G. (1992). Developing a geographic expert system for regional mapping of volcanogenic massive sulfide (VMS) deposit potential. Nonrenewable Resources, 1, 112–124.
Robb, L. J. (2005). Introduction to ore-forming processes (p. 373). Hoboken: Blackwell.
Robb, L. J., Freeman, L. A., & Armstrong, R. A. (2000). Nature and longevity of hydrothermal fluid flow and mineralisation in granites of the Bushveld Complex, South Africa. Transactions of the Royal Society of Edinburgh, 91, 269–281.
Robb, L. J., Robb, V. M., & Walraven, F. (1994). The Albert Silver Mine revisited: toward a model for polymetallic mineralisation in granites of the Bushveld Complex, South Africa. Exploration and Mining Geology, 3, 219–230.
Rozendaal, A., Misiewicz, J. E., & Scheepers, R. (1995). The tin zone: sediment-hosted hydrothermal tin mineralization at Rooiberg, South Africa. Mineralium Deposita, 30, 178–187.
Rozendaal, A., Toros, M. S., & Anderson, J. R. (1986). The Rooiberg tin deposits, west-central Transvaal. In C. R. Anhaeusser & S. Maske (Eds.), Mineral deposits of South Africa (Vol. II, pp. 1307–1327). Johannesburg: Geological Society of Southern Africa.
Schürmann, L.W., & Harmer, R.E. (1998). Rare earth elements. In: Wilson, M.G.C., & Anhaeusser, C.R. (Eds.), The mineral resources of South Africa. Handbook of the Council for Geoscience, 16, pp. 259–266.
Schweitzer, J. K., & Hatton, C. J. (1995). Chemical alteration within the volcanic roof rocks of the Bushveld Complex. Economic Geology, 90, 2216–2231.
Schweitzer, J. K., Hatton, C. J., & De Waal, S. A. (1995). Regional lithochemical stratigraphy of the Rooiberg Group, Upper Transvaal Supergroup: a proposed new subdivision. South African Journal of Geology, 98, 245–255.
Smits, G. (1986). Hydrothermal copper mineralisation of the Rooibokkop-Boschhoek prospect, Eastern Bushveld Complex. In C. R. Anhaeusser & S. Maske (Eds.), Mineral deposits of South Africa (Vol. II, pp. 1329–1335). Johannesburg: Geological Society of Southern Africa.
Strauss, C. A. (1954). The geology and mineral deposits of the Potgietersrus tin-fields. Geological Survey of South Africa Memior, 46, 241.
Taylor, R. G., & Pollard, P. J. (1989). Pervasive hydrothermal alteration in tin-bearing granites and implications for the evolution of ore-bearing magmatic fluids. Canada Institute of Mining and Metallurgy Specification, 39, 86–95.
Twist, D. (1985). Geochemical evolution of the Rooiberg siliceous lavas in the Loskop Dam area, southeastern Bushveld. Economic Geology, 80, 1153–1165.
Venkataraman, G., Babu Madhavan, B., Ratha, D. S., Antony, J. P., Goyal, R. S., Banglani, S., et al. (2000). Spatial modeling for base-metal mineral exploration through integration of geological data sets. Natural Resources Research, 9, 27–42.
Von Gruenewaldt, G., Sharpe, M. R., & Hatton, C. J. (1985). The Bushveld Complex: Introduction and review. Economic Geology, 80, 803–812.
Von Gruenewaldt, G., & Strydom, J. H. (1985). Geochemical distribution patterns surrounding tin-bearing pipes and the origin of the mineralizing fluids at the Zaaiplaats Tin Mine. Potgietersrus district, Economic Geology, 80, 1202–1211.
Walraven, F. (1988). Notes on the age and genetic relationships of the Makhutso granite, Bushveld complex, South Africa. Chemical Geology, 72, 17–28.
Walraven, F., Armstrong, R. A., & Kruger, F. J. (1990). A chronostratigraphy framework for the north-central Kaapvaal Craton, the Bushveld Complex and Vredefort structure. Tectonophyscis, 171, 23–48.
Walraven, F., & Hattingh, E. (1993). Geochronology of the Nebo granite, Bushveld Complex. South African Journal of Geology, 96, 31–41.
Wyborn, L.A.I., Heinrich, C.A., Jaques, A.L., 1994. Australian Proterozoic mineral systems: essential ingredients and mappable criteria (abs.). In: Hallenstein, P.C. (Ed.), Australian Mining Looks North—the Challenges and Choices. Australian Institute of Mining and Metallurgy Publication Series, vol. 5, pp. 109–115.
Zadeh, L. A. (1965). Fuzzy sets. Institute of Electric and Electronic Engineering, Information and Control, 8, 338–353.
Acknowledgments
The authors would like to thank the Council for Geoscience for the geochemical data and geoscientific data and for the funding the project. We also would like to thank our colleagues, Dr. Bisrat Yibas and Mr. Abdul Kenan, for their review and inputs to improve the manuscript. We thank the two anonymous reviewers and the chief editor of Natural Resources Research for their constructive comments that helped us improve this paper.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Mutele, L., Billay, A. & Hunt, J.P. Knowledge-Driven Prospectivity Mapping for Granite-Related Polymetallic Sn–F–(REE) mineralization, Bushveld Igneous Complex, South Africa. Nat Resour Res 26, 535–552 (2017). https://doi.org/10.1007/s11053-017-9325-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11053-017-9325-8