2411-3336 2541-9404 Записки Горного института Journal of Mining Institute Санкт-Петербургский горный университет императрицы Екатерины ΙΙ Empress Catherine II Saint Petersburg Mining University 10.31897/PMI.2021.6.4 pmi-13882 https://pmi.spmi.ru/pmi/article/view/13882 Геология Geology Indicator role of rare and rare-earth elements of the Northwest manganese ore occurrence (South Africa) in the genetic model of supergene manganese deposits Индикаторная роль редких и редкоземельных элементов Северо-Западного рудопроявления марганца (ЮАР) в генетической модели гипергенных марганцевых месторождений Evdokimov Aleksandr N. Евдокимов А. Н. Evdokimov Aleksandr N. evdokimov_an@spmi.ru Санкт-Петербургский горный университет (Россия) Saint Petersburg Mining University (Russia) Pharoe Benedict L. Пхарое Б. Л. Pharoe Benedict L. benedictpharoe1@gmail.com Санкт-Петербургский горный университет (Россия) Saint Petersburg Mining University (Russia) 27 12 2021 2021 252 814 825 20 08 2020 30 11 2021 27 12 2021 © 2021 А. Н. Евдокимов, Б. Л. Пхарое © 2021 Aleksandr N. Evdokimov, Benedict L. Pharoe 2021 А. Н. Евдокимов, Б. Л. Пхарое Aleksandr N. Evdokimov, Benedict L. Pharoe Эта статья доступна по лицензии Creative Commons Attribution 4.0 International (CC BY 4.0) This article is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0) https://pmi.spmi.ru/pmi/article/view/13882

Проанализировано содержание ряда редких и редкоземельных элементов в породах Северо-Западного рудопроявления марганца, приуроченного к неоархейским доломитам серии Мальмани Трансваальского бассейна. Выполнен анализ 30 образцов марганцевых руд и вмещающих пород методами ICP-MS и XRF. Для расчета и нормирования данных использован геохимический стандарт – средние значения постархейского австралийского глинистого сланца (PAAS). Отношения содержаний элементов относительно PAAS обнаруживают присутствие аномалии легких редкоземельных элементов в марганцевых рудах. Положительные аномалии содержания Ce и отрицательные аномалии содержания Y свидетельствуют о гидрогенетическом типе осадкообразования рудных минералов из марганцевоносных водных растворов. Это согласуется с соотношениями элементов: Ce и YSN/HoSN, Ce и Nd, Fe – Mn – (Co + Ni + Cu)∙10. Отчетливая корреляция содержаний редкоземельных элементов в марганцевых конкрециях и в подстилающих Мальманийских доломитах указывают на их тесную генетическую связь. Отрицательные Ce и положительные Y аномалии в минералах марганцевого вада указывают на различия условий их образования. Марганцевый вад образовался раньше остальной части руды при активном участии микроорганизмов.

The authors analyzed the content of a number of rare and rare-earth elements in the rocks of the Northwest manganese ore occurrence, confined to the Neoarchean dolomites of the Malmani series of the Transvaal Basin. 30 samples of manganese ores and host rocks were analyzed by ICP-MS and XRF methods. Average values of Post-Archean Australian Shale (PAAS) were used as the geochemical standard for data calculation and normalization. The concentrations of elements normalized on PAAS reveal the LREE anomaly in manganese ores. Positive Ce and negative Y–anomalies indicate the hydro-genetical type of sedimentation of ore minerals from manganese-bearing aqueous solutions. This is consistent with the ratios of the elements: Ce and Y SN/Ho SN, Ce and Nd, Fe – Mn – (Co + Ni + Cu) × 10. A clear correlation between the contents of rare-earth elements in manganese nodules and the underlying Malmani dolomites indicates their close genetic relationship. Negative Ce and positive Y–anomalies in manganese wad minerals indicate differences in the conditions of their formation. The manganese wad formed earlier than the rest of the ore with the active participation of microorganisms.

 Ключевые слова марганец гипергенное оруденение редкоземельные элементы кора выветривания ЮАР Keywords manganese supergene mineralization rare-earth elements weathering crust South Africa Кулешов В.Н. Марганцевые породы и руды: геохимия изотопов, генезис, эволюция рудогенеза: Монография. М.: Научный мир, 2013. 508 с. Kuleshov V.N. Manganese rocks and ores: isotope geochemistry, genesis, evolution of ore genesis: Monografiya. Moscow: Nauchnyi mir, 2013, p. 508 (in Russian). Цыкин Р.А. Гипергенные марганцевые руды Центральной Сибири // Журнал Сибирского федерального университета. Техника и технологии. 2008. Т. 1. № 1. С. 3-16. Tsykin R.A. Hypergene Manganese Ores of Central Siberia. Journal of Siberian Federal University. Engineering & Technologies. 2008. Vol. 1. N 1, p. 3-16 (in Russian). Юдович Я.Э. Геохимия марганца в процессах гипергенеза: обзор / Я.Э.Юдович, М.П.Кетрис // Биосфера. 2013. Т. 5. № 1. С. 21-36. Yudovich Ya.E., Ketris M.P. Manganese geochemistry in supergene processes. A review. Biosfera. 2013. Vol. 5. N 1, p. 21-36 (in Russian). Юдович Я.Э. Основные закономерности геохимии марганца / Я.Э.Юдович, М.П.Кетрис. Сыктывкар: Коми научный центр Уральского отделения Российской академии наук, 2013. 40 с. Yudovich Ya.E., Ketris M.P. Basic laws of manganese geochemistry. Syktyvkar: Komi nauchnyi tsentr Uralskogo otdeleniya Rossiiskoi akademii nauk, 2013, p. 40 (in Russian). A new Discrimination scheme for oceanic ferromanganese deposits using high field strength and rare earth elements / P.Josso, E.Pelleter, O.Pourret et al. // Ore Geology Reviews. 2017. Vol. 87. P. 3-15. DOI: 10.1016/j.oregeorev.2016.09.003 Josso P., Pelleter E., Pourret O. et al. A new Discrimination scheme for oceanic ferromanganese deposits using high field strength and rare earth elements. Ore Geology Reviews. 2017. Vol. 87, p. 3-15. DOI: 10.1016/j.oregeorev.2016.09.003 Bau M. Distribution of yttrium and rare-earth elements in the Penge and Kuruman iron-formations, Transvaal Supergroup, South Africa / M.Bau, P.Dulski // Precambrian Research. 1996. Vol. 79. Iss. 1-2. P. 37-55. DOI: 10.1016/0301-9268(95)00087-9 Bau M., Dulski P. Distribution of yttrium and rare-earth elements in the Penge and Kuruman iron-formations, Transvaal Supergroup, South Africa. Precambrian Research. 1996. Vol. 79. Iss. 1-2, p. 37-55. DOI: 10.1016/0301-9268(95)00087-9 Beukes N.J. Manganese deposits of Africa / N.J.Beukes, E.W.Swindell, H.Wabo // Episodes Journal of International Geoscience. 2016. Vol. 39. Iss. 2. P. 285-317. DOI: 10.18814/epiiugs/2016/v39i2/95779 Beukes N.J., Swindell E.W., Wabo H. Manganese deposits of Africa. Episodes Journal of International Geoscience. 2016. Vol. 39. Iss. 2. P. 285-317. DOI: 10.18814/epiiugs/2016/v39i2/95779 Bonatti E. Classification and genesis of submarine iron manganese deposits / E.Bonatti, T.Kraemer, H.Rydell // Ferromanganese Deposits of the Ocean Floor, 1972. P. 473-489. Bonatti E., Kraemer T., Rydell H. Classification and genesis of submarine iron manganese deposits. Ferromanganese Deposits of the Ocean Floor, 1972, p. 473-489. Button A. The stratigraphic history of the Malmani Dolomite in the eastern and north-eastern Transvaal // South African Journal of Geology. 1973. Vol. 76. Iss. 3. P. 229-247. DOI: 10.10520/AJA10120750_282 Button A. The stratigraphic history of the Malmani Dolomite in the eastern and north-eastern Transvaal. South African Journal of Geology. 1973. Vol. 76. Iss. 3, p. 229-247. DOI: 10.10520/AJA10120750_282 Button A. Geochemistry of the Malmani Dolomite of the Transvaal Supergroup in the Northeastern Transvaal // Economic Geology Research Unit. 1975. Vol. 97. P. 1-21. Button A. Geochemistry of the Malmani Dolomite of the Transvaal Supergroup in the Northeastern Transvaal. Economic Geology Research Unit. 1975. Vol. 97, p. 1-21. Burke K. The African erosion surface: a continental-scale synthesis of geomorphology, tectonics, and environmental change over the past 180 million years / K.Burke, Y.Gunnell // Memoir of the Geological Society of America. 2008. Vol. 201. P. 66. Burke K., Gunnell Y. The African erosion surface: a continental-scale synthesis of geomorphology, tectonics, and environmental change over the past 180 million years. Memoir of the Geological Society of America. 2008. Vol. 201, p. 66. Comparison of the partitioning behaviours of yttrium, rare earth elements, and titanium between hydrogenetic marine ferromanganese crusts and seawater / M.Bau, A.Koschinsky, P.Dulski, J.R.Hein // Geochimca et Cosmochima Acta. 1996. Vol. 60. Iss. 10. P. 1709-1725. DOI: 10.1016/0016-7037(96)00063-4 Bau M., Koschinsky A., Dulski P., Hein J.R. Comparison of the partitioning behaviours of yttrium, rare earth elements, and titanium between hydrogenetic marine ferromanganese crusts and seawater. Geochimca et Cosmochima Acta. 1996. Vol. 60. Iss. 10, p. 1709-1725. DOI: 10.1016/0016-7037(96)00063-4 Critical metals in manganese nodules from the Cook Islands EEZ, abundances and distributions / R.Hein, F.Spinardi, N.Okamoto Mizell et al. // Ore Geology Reviews. 2015. Vol. 68. P. 97-116. DOI: 10.1016/j.oregeorev.2014.12.011 Hein R., Spinardi F., Okamoto Mizell N. et al. Critical metals in manganese nodules from the Cook Islands EEZ, abundances and distributions. Ore Geology Reviews. 2015. Vol. 68, p. 97-116. DOI: 10.1016/j.oregeorev.2014.12.011 Deep Sea Minerals: Manganese Nodules, a physical, biological, environmental, and technical review / E.Baker, Y.Beaudoin (Editors) // SPC. 2013. Vol. 1B. Secretariat of the Pacific Community. 51 p. Deep Sea Minerals: Manganese Nodules, a physical, biological, environmental, and technical review. E.Baker, Y.Beaudoin (Editors). SPC. 2013. Vol. 1B. Secretariat of the Pacific Community, p. 51. de Villiers J. The manganese deposits of the Union of South Africa. Geological Survey of South Africa Handbook 2. Pretoria: Government Printer, 1960. 263 p. de Villiers J. The manganese deposits of the Union of South Africa. Geological Survey of South Africa Handbook 2. Pretoria: Government Printer, 1960, p. 263. de Villiers P. The geology and mineralogy of the Kalahari Manganese Field north of Sishen, Cape Province. Pretoria: Geological Survey of South Africa, Memoir 59, 1970, p. 84. de Villiers P. The geology and mineralogy of the Kalahari Manganese Field north of Sishen, Cape Province. Pretoria: Geological Survey of South Africa, Memoir 59, 1970, p. 84. Discriminating between different genetic types of marine ferro-manganese crusts and nodules based on rare earth elements and yttrium / M.Bau, K.Schimdt, A.Koschinsky et al. // Chemical Geology. 2014. Vol. 381. P. 1-9. DOI: 10.1016/j.chemgeo.2014.05.004 Bau M., Schimdt K., Koschinsky A. et al. Discriminating between different genetic types of marine ferro-manganese crusts and nodules based on rare earth elements and yttrium. Chemical Geology. 2014. Vol. 381, p. 1-9. DOI: 10.1016/j.chemgeo.2014.05.004 Eriksson K. Cyclic sedimentation in the Malmani Dolomite, Potchefstroom Synclinorium // Geological Society of South Africa. 1972. Vol. 75. Iss. 2. P. 85-97. DOI: 10520/AJA10120750_2731 Eriksson K. Cyclic sedimentation in the Malmani Dolomite, Potchefstroom Synclinorium. Geological Society of South Africa. 1972. Vol. 75. Iss. 2, p. 85-97. DOI: 10520/AJA10120750_2731 Frankel J. Manganese ores from the Kuruman district, Cape Province, South Africa // Economic Geology. 1958. Vol. 53. P. 577-597. DOI: 10.2113/gsecongeo.53.5.577 Frankel J. Manganese ores from the Kuruman district, Cape Province, South Africa. Economic Geology. 1958. Vol. 53, p. 577-597. DOI: 10.2113/gsecongeo.53.5.577 Geochemistry and Re-Os systematics of manganese deposits from the Santa Rosalia Basin and adjacent area in Baja California Sur, Mexico / R.Del Rio Salas, J.Ruiz, L.Ochoa-Landin et al. // Mineralium Deposita. 2008. Vol. 43. Iss. 4. P. 467-482. DOI: 10.1007/s00126-008-0177-3 Del Rio Salas R., Ruiz J., Ochoa-Landin L. et al. Geochemistry and Re-Os systematics of manganese deposits from the Santa Rosalia Basin and adjacent area in Baja California Sur, Mexico. Mineralium Deposita. 2008. Vol. 43. Iss. 4, p. 467-482. DOI: 10.1007/s00126-008-0177-3 Gutzmer, J. Genesis and alteration of the Kalahari and Postmasburg Manganese Deposits, Griqualand West, South Africa: PhD dissertation, University of Johannesburg. South Africa, 1996, p. 490. Gutzmer, J. Genesis and alteration of the Kalahari and Postmasburg Manganese Deposits, Griqualand West, South Africa: PhD dissertation, University of Johannesburg. South Africa, 1996, p. 490. Heshmatbehzadi K. Metallogeny of manganese and ferromanganese ores in Baft Ophiolitic Mélange, Kerman, Iran / K.Heshmatbehzadi, J.Shahabpour // Australian Journal of Basic and Applied Sciences. 2010. Vol. 4. Iss. 2. P. 302-313. Heshmatbehzadi K., Shahabpour J. Metallogeny of manganese and ferromanganese ores in Baft Ophiolitic Mélange, Kerman, Iran. Australian Journal of Basic and Applied Sciences. 2010. Vol. 4. Iss. 2, p. 302-313. Kleyenstuber A. The mineralogy of the manganese bearing Hotazel Formation of the Proterozoic Transvaal Sequence in Griqualand West, South Africa // Transactions of the Geological Society of South Africa. 1984. Vol. 87. Iss. 3. P. 257-272. Kleyenstuber A. The mineralogy of the manganese bearing Hotazel Formation of the Proterozoic Transvaal Sequence in Griqualand West, South Africa. Transactions of the Geological Society of South Africa. 1984. Vol. 87. Iss. 3, p. 257-272. Manganese nodules in the Miocene Bahia Inglesa Formation, north-central Chile: Petrography, geochemistry, genesis and palaeoceanographic significance / L.E.Achurra, J.P.Lacassie, J.P.Le Roux et al. // Sedimentary geology. 2009. Vol. 217. Iss. 1-4. P. 128-139. DOI: 10.1016/j.sedgeo.2009.03.016 Achurra L.E., Lacassie J.P., Le Roux J.P. et al. Manganese nodules in the Miocene Bahia Inglesa Formation, north-central Chile: Petrography, geochemistry, genesis and palaeoceanographic significance. Sedimentary geology. 2009. Vol. 217. Iss. 1-4, p. 128-139. DOI: 10.1016/j.sedgeo.2009.03.016 Manganese ores in Tunisia: Genetic constraints from trace element geochemistry and mineralogy / H.Garnit, D.Kraemer, S.Bouhlel et al. // Ore Geology Reviews. 2020. Vol. 120. № 103451. DOI: 10.1016/j.oregeorev.2020.103451 Garnit H., Kraemer D., Bouhlel S. et al. Manganese ores in Tunisia: Genetic constraints from trace element geochemistry and mineralogy. Ore Geology Reviews. 2020. Vol. 120. N 103451. DOI: 10.1016/j.oregeorev.2020.103451 Maynard J.B. The chemistry of manganese ores through time: a signal of increasing diversity of earth-surface environments // Economic Geology. 2010. Vol. 105. Iss. 3. P. 535-552. DOI: 10.2113/gsecongeo.105.3.535 Maynard J.B. The chemistry of manganese ores through time: a signal of increasing diversity of earth-surface environments. Economic Geology. 2010. Vol. 105. Iss. 3, p. 535-552. DOI: 10.2113/gsecongeo.105.3.535 Mineralogy, geochemistry and genesis of the post-Gondwana supergene manganese deposit of the Carletonville-Ventersdorp area, North West Province, South Africa / B.K.Pharoe, A.N.Evdokimov, I.M.Gembitskaya, Y.Y.Bushuev // Ore Geology Reviews. 2020. Vol. 120. № 103372. DOI: 10.1016/j.oregeorev.2020.103372 Pharoe B.K., Evdokimov A.N., Gembitskaya I.M., Bushuev Y.Y. Mineralogy, geochemistry and genesis of the post-Gondwana supergene manganese deposit of the Carletonville-Ventersdorp area, North West Province, South Africa. Ore Geology Reviews. 2020. Vol. 120. N 103372. DOI: 10.1016/j.oregeorev.2020.103372 Nath B.B. Geochemical constraints on the hydrothermal origin of ferromanganese incrustations from the Rodriguez triple junction, Indian Ocean / B.B.Nath, W.L.Pluger, I.Roelandts // Geological Society of London, Special Publication. 1997. Vol. 119. P. 199-211. DOI: 10.1144/GSL.SP.1997.119.01.13 Nath B.B. Nath B.B., Pluger W.L., Roelandts I. Geochemical constraints on the hydrothermal origin of ferromanganese incrustations from the Rodriguez triple junction, Indian Ocean. Geological Society of London, Special Publication. 1997. Vol. 119, p. 199-211. DOI: 10.1144/GSL.SP.1997.119.01.13 Nel C. The Mamatwan manganese mine of the Kalahari manganese Field / C.Nel, N.Beukes, J.De Villiers // Mineral Deposits of Southern Africa. Geological Society of South Africa. 1986. Vol. 1. P. 963-978. Nel C., Beukes N., De Villiers J. The Mamatwan manganese mine of the Kalahari manganese Field. Mineral Deposits of Southern Africa. Geological Society of South Africa. 1986. Vol. 1, p. 963-978. Nicholson K. Manganese ores of the Ghoriajhor-Monmunda area, Sundergarh District, Orissa, India: geochemical evidence for a mixed Mn source / K.Nicholson, V.K.Nayak, J.K.Nanda // Geological Society of London, Special Publication. 1997. Vol. 119. Iss. 1. P. 117-121. DOI: 10.1144/GSL.SP.1997.119.01.08 Nicholson K., Nayak V.K., Nanda J.K. Manganese ores of the Ghoriajhor-Monmunda area, Sundergarh District, Orissa, India: geochemical evidence for a mixed Mn source. Geological Society of London, Special Publication. 1997. Vol. 119. Iss. 1, p. 117-121. DOI: 10.1144/GSL.SP.1997.119.01.08 Partridge T.C. Geomorphic evolution of Southern Africa since Mesozoic / T.C.Partridge, R.R.Maud // South African Journal of Geology. 1987. Vol. 90. Iss. 2. P. 179-208. DOI: 10520/AJA10120750_958 Partridge T.C., Maud R.R. Geomorphic evolution of Southern Africa since Mesozoic. South African Journal of Geology. 1987. Vol. 90. Iss. 2, p. 179-208. DOI: 10520/AJA10120750_958 Pharoe B.K. Stratigraphy of the pedogenic manganese nodules in the Carletonville area, North West Province of South Africa: A case study of the General Nice Manganese Mine / B.K.Pharoe, K.Liu // Journal of African Earth Sciences. 2018. Vol. 143. P. 79-101. DOI: 10.1016/j.jafrearsci.2018.03.002 Pharoe B.K., Liu K. Stratigraphy of the pedogenic manganese nodules in the Carletonville area, North West Province of South Africa: A case study of the General Nice Manganese Mine. Journal of African Earth Sciences. 2018. Vol. 143, p. 79-101. DOI: 10.1016/j.jafrearsci.2018.03.002 Post-Gondwana pedogenic ferromanganese deposits, ancient soil profiles, African land surfaces and palaeoclimate change on the Highveld of South Africa / H.S.van Niekerk, N.J.Beukes, J.Gutzmer // Journal of African Earth Sciences. 1999. Vol. 29. Iss. 4. P. 761-781. DOI: 10.1016/S0899-5362(99)00128-1 van Niekerk H.S., Beukes N.J., Gutzmer J. Post-Gondwana pedogenic ferromanganese deposits, ancient soil profiles, African land surfaces and palaeoclimate change on the Highveld of South Africa. Journal of African Earth Sciences. 1999. Vol. 29. Iss. 4, p. 761-781. DOI: 10.1016/S0899-5362(99)00128-1 Rare earth elements and yttrium in ferromanganese deposits from the South China Sea: distribution, composition and resource considerations / Yi Zhong, Zhong Chen, Francisco Javier Gonzalez et al. // Acta Oceanologica Sinic. 2019. Vol. 37. Iss. 7. P. 41-54. DOI: 10.1007/s13131-018-1205-5 Yi Zhong, Zhong Chen, Francisco Javier Gonzalez et al. Rare earth elements and yttrium in ferromanganese deposits from the South China Sea: distribution, composition and resource considerations. Acta Oceanologica Sinic. 2019. Vol. 37. Iss. 7, p. 41-54. DOI: 10.1007/s13131-018-1205-5 Roy S. Environments and processes of manganese deposits // Economic Geology. 1992. Vol. 87. № 5. P. 1218-1236. DOI: 10.2113/gsecongeo.87.5.1218 Roy S. Environments and processes of manganese deposits. Economic Geology. 1992. Vol. 87. N 5, p. 1218-1236. DOI: 10.2113/gsecongeo.87.5.1218 Roy S. Sedimentary manganese metallogenesis in response to the evolution of the Earth system // Earth Science reviews. 2006. Vol. 77. Iss. 4. P. 273-305. DOI: 10.1016/j.earscirev.2006.03.004 Roy S. Sedimentary manganese metallogenesis in response to the evolution of the Earth system. Earth Science reviews. 2006. Vol. 77. Iss. 4, p. 273-305. DOI: 10.1016/j.earscirev.2006.03.004 Sun S. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes / S.Sun, W.McDonough // Geological Society of London. 1989. Vol. 42. P. 313-345. DOI: 10.1144/GSL.SP.1989.042.01.19 Sun S., McDonough W. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. Geological Society of London. 1989. Vol. 42, p. 313-345. DOI: 10.1144/GSL.SP.1989.042.01.19 Supergene ferromanganese wad deposits derived from Permian Karoo Strata along the late Cretaceous-mid-Tertiary African land surface, Ryedale, South Africa / A.Pack, J.Gutzmer, N.Beukes, H.Van Niekerk // Economic Geology. 2000. Vol. 95. № 1. P. 203-220. DOI: 10.2113/gsecongeo.95.1.203 Pack A., Gutzmer J., Beukes N., Van Niekerk H. Supergene ferromanganese wad deposits derived from Permian Karoo Strata along the late Cretaceous-mid-Tertiary African land surface, Ryedale, South Africa. Economic Geology. 2000. Vol. 95. N 1, p. 203-220. DOI: 10.2113/gsecongeo.95.1.203 Taylor S.R. The Continental Crust: Its Composition and Evolution / S.R.Taylor, S.M.Mclennan. Oxford : Blackwell Scientific, 1985. 312 p. Taylor S.R., Mclennan S.M. The Continental Crust: Its Composition and Evolution. Oxford: Blackwell Scientific, 1985, p. 312. The Role of Hydrothermal Activity in the Formation of Karst-Hosted Manganese Deposits of the Postmasburg Mn Field, Northern Cape Province, South Africa / J.Fairey, J.Timmerman, M.Sudo, H.Tsikos // Minerals. 2019. Vol. 9. Iss. 7. № 408. DOI: 10.3390/min9070408 Fairey J., Timmerman J., Sudo M., Tsikos H. The Role of Hydrothermal Activity in the Formation of Karst-Hosted Manganese Deposits of the Postmasburg Mn Field, Northern Cape Province, South Africa. Minerals. 2019. Vol. 9. Iss. 7. N 408. DOI: 10.3390/min9070408 Toth J. Deposition of submarine crusts rich in manganese and iron // Geological Society of America Bulletin. 1980. Vol. 91. Iss. 1. P. 44-54. DOI: 10.1130/0016-7606(1980)91<44:DOSCRI>2.0.CO;2 Toth J. Deposition of submarine crusts rich in manganese and iron. Geological Society of America Bulletin. 1980. Vol. 91. Iss. 1, p. 44-54. DOI: 10.1130/0016-7606(1980)91<44:DOSCRI>2.0.CO;2 Tsikos H. Petrographic and geochemical constraints on the origin and post-depositional history of the Hotazel Iron-Manganese Deposits, Kalahari Manganese Field, South Africa: PhD dissertation. Rhodes University, South Africa, 1999. 292 p. Tsikos H. Petrographic and geochemical constraints on the origin and post-depositional history of the Hotazel Iron-Manganese Deposits, Kalahari Manganese Field, South Africa: PhD dissertation. Rhodes University, South Africa, 1999, p. 292. Vafeas N.A. New evidence for the early onset of supergene alteration along the Kalahari unconformity / N.A.Vafeas, L.C.Blignaut, K.S.Viljoenm // South African Journal of Geology. 2018. Vol. 121. № 2. P. 157-170. DOI: 10.25131/sajg.121.0012 Vafeas N.A., Blignaut L.C., Viljoenm K.S. New evidence for the early onset of supergene alteration along the Kalahari unconformity. South African Journal of Geology. 2018. Vol. 121. N 2, p. 157-170. DOI: 10.25131/sajg.121.0012 Varentsov I.M. Manganese Ores of Supergene Zone: Geochemistry of Formation. Springer, 1996. Vol. 8. 302 p. DOI: 10.1007/978-94-017-2174-5 Varentsov I.M. Manganese Ores of Supergene Zone: Geochemistry of Formation. Springer, 1996. Vol. 8, p. 302. DOI: 10.1007/978-94-017-2174-5