Papers by Benedict Pharoe
Proceedings of the National Academy of Sciences, India Section A: Physical Sciences
The study on differentiation of chemical components in quenched volcanics from the Etna, Tolbachi... more The study on differentiation of chemical components in quenched volcanics from the Etna, Tolbachik and Hawaiian fissure zones was carried out under simulated temperature/pressure (T/P) conditions reflecting real-time conditions in the early stages of magmatic eruptions. The simulation was performed under high-pressure chamber apparatus, and the rocks were then subjected to high T/P conditions resulting in basaltic melts. Various temperature and pressure conditions were adjusted from the apparatus to allow for different rates of magmatic cooling and crystallization. The scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS-microanalysis) was then used to study the quenched glasses with the aim of identifying major element partitioning based on micro-heterogeneity of melts structures. The microscopic study of the experimental melts and their comparisons with natural melts under the electron microscopes indicate the existence of two distinct liquids which ...
Геология и геофизика Юга России, Dec 20, 2020
Благодарность: Работа выполнена при финансовой поддержке Министерства образования ЮАР. Выражается... more Благодарность: Работа выполнена при финансовой поддержке Министерства образования ЮАР. Выражается благодарность Санкт-Петербургскому горному университету за возможность учиться в аспирантуре и за использование ряда приборов: SEM-EDS, XRD, поляризационные микроскопы и другие инструменты.
Геология и геофизика Юга России, 2020
Северо-западный регион ЮАР до недавнего времени не являлся промышленно марганценосным. Однако рез... more Северо-западный регион ЮАР до недавнего времени не являлся промышленно марганценосным. Однако результаты изучения последних лет дают основание думать, что здесь могут быть залежи марганцевых руд. Марганцевое оруденение в этом регионе встречается в виде марганцевых конкреций, порошкообразного марганцевого вада и марганцевых корок в коре выветривания. Марганцевые конкреции приурочены к аллювиальной части «Westwits alluvium» рудного разреза и марганцевый вад накоплялся в карстовых структурах, образовавшихся в результате приповерхностного выветривания, выщелачивания и растворения подстилающих марганценосных неоархейских доломитов. Предполагается два потенциальных источника марганца: первый расположен непосредственно под рудным телом, а второй – на существенном удалении от него. Если первый источник рудного вещества поставлял марганец из подстилающих доломитов в процессе их выветривания, то второй вариант подразумевает существенный перенос металла из неизвестных коренных источников, расп...
Russian Journal of Earth Sciences, 2020
Sustainability, 2022
In the last few decades, shale gas resources have attracted much global attention as potential so... more In the last few decades, shale gas resources have attracted much global attention as potential sources for clean and affordable energy. Due to this fact, coupled with the increasing energy shortfall, shale gas has become an increasingly attractive energy prospect from both an environmental and economic perspective. This development has led to the rapid growth in the number of researchers and publications in the field of shale gas. Although there are few review articles on the state of research on shale gas, the literature lacked a bibliometric analysis. This study is intended to fill the research gap by carrying out a bibliometric analysis of 9247 shale gas articles that were published between 2010 and 2020. The Web of Science database was used to collect the data. The analysis was performed to identify the most productive authors, institutions, countries, and sources, and to visualize existing collaborations as well as provide valuable information which could form the basis for est...
Journal of African Earth Sciences, 2020
Abstract The paper presents the results obtained from petrographic and lithogeochemical studies o... more Abstract The paper presents the results obtained from petrographic and lithogeochemical studies of Tertiary alluvial deposits in the Buchansvale 61 IQ farm around the Ventersdorp region. These are unconsolidated manganese-bearing sediments of alluvial origin, currently making up the West-wits alluvium which overlies the manganiferous dolostones of the Transvaal Basin in a weathering crust. Mineralogically, the alluvial deposits are composed mainly of detrital quartz, feldspars, and grains of zircon and traces of ilmenite. Authigenic mineral phases are predominantly composed of clays and iron oxides, cryptomelane (KMn8O16), hollandite/romanechite (BaMn8O16/10), spinel-galaxite (Mn2+Al2O4) and other manganese oxides/oxyhydroxides. Quartz modal content makes up an average of 70% of all detrital framework grains. The content of feldspar, cement minerals and clays seldom exceeds 20%. An extensive diagenetic replacement of detrital grains and early formed authigenic mineral and cements by Mn oxides is evident. The study applied the method of modal composition analytical study to count the percent ratios of framework grains (grains of quartz, feldspar, pyroxene, amphibole, mica, etc.) in the samples in order to reconstruct their source regions. According to the observations made from the data interpretation, the probable sources of the sediments were inferred from old recycled orogens and cratonic interiors. It was further noticed that the sediments are characterized by arkoses to subarkoses and subordinate quartz arenite. These observations indicate the near source regions, most probably a combination of Pretoria Group sediments and Black Reef Quartzite. Sedimentation occurred in a low-lying plain characterized by tropical-moderately humid and subhumid climates. Here, in combination with increased pH of the basinal waters which is attributable to surficial weathering of the Malmani Dolostones and intensive oxidation, a replacement of detrital grains with manganese dioxide precipitates became prominent.
Ore Geology Reviews, 2020
Abstract The post-Gondwana period is characterized by some of the unique geologic events which sh... more Abstract The post-Gondwana period is characterized by some of the unique geologic events which shaped the present geomorphological landscape in various parts of the world. One of the most important and unique features associated with this geologic period is the formation of high valence state (Mn4+) manganese oxides in weathering crusts of uplifted landscapes, underlain by manganiferous protores. The study of these manganese oxide minerals has proven not only to be industrially beneficial but they also provide insights into the evolution of the paleo surfaces, especially in tropical regions. Here we present new results on mineralogy, geochemistry and genetic model of the North West Manganese Deposit in the General Nice lease area. The General Nice ore deposit represents a near surface accumulation of supergene manganese wad and nodule deposit in a weathering crust underlain by manganiferous dolostones of the Transvaal Malmani Subgroup. The ore formation is attributed to in situ dissolution, leaching and surficial weathering of the underlying manganiferous dolostones of the Malmani Subgroup and carbonaceous protore of the Waterval Saprolite in a typically oxidic lacustrine setting. The combined processes led to the release and mobilization of Mn rich colloidal particles (sols) into the overlying water column of the depository, which later precipitated as manganese nodules upon interaction with the alluvial sediments which acted as substrates and centers of accretion. Mineralogical studies conducted on both scanning electron microscope (SEM –EDS) and X-ray diffraction (XRD) indicated the predominance of the manganese oxides; romanechite, cryptomelane and galaxite as major manganese oxide phases and pyrolusite, vernadite occurring in minute quantities. Diagenetic features indicate alteration of pyrolusite and its replacement by romanechite. This is evident from the romanechite veinlets cross-cutting the fractured groundmass of pyrolusite. Galaxite appears to represent the latest stage of authigenic mineral precipitation, and occurs mostly around the pore-spaces. Other mineral components include hematite/goethite, clays, muscovite, silica and inclusions of ilmenite and detrital zircon. These accessory minerals occur either in the form of nuclei grains or inclusions in manganese oxide cement.
Записки Горного института, 2021
The authors analyzed the content of a number of rare and rare-earth elements in the rocks of the ... more 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 manga...
Zapiski Gornogo Instituta, May 25, 2021
The Northwest manganese ore mineralisation is located at a relative distance from traditionally k... more The Northwest manganese ore mineralisation is located at a relative distance from traditionally known manganese mining areas in a new manganese-bearing region (Highveld) in the Northwest Province, Republic of South Africa. The ore occurrence was studied on farms: Buchansvale 61 IQ, Weltevreden 517 JQ, Rhenosterhoek 343 JP and Kafferskraal 306 JP. The data obtained from studying the geology of the area pointed out to interests regarding the development criterias for search of similar ore mineralisations in the northwest region of South Africa. The ore occurs predominantly in the form of powdered manganese wad, manganese nodules and crusts, confined to the karstic structures of the upper section of the dolomites. X-ray powder diffraction (XRD), Scanning electron microscopy with energy dispersive link (SEM-EDS) and X-ray fluorescence were utilized to unveil the mineral and chemical composition of the ore samples. The present study therefore presents the results on both chemical and mineral composition of manganese ores, and their depth and longitudinal distribution. Karstic areas causing an increased local thickness of the ore body were identified. The geochemical and microspcopic study of the ores indicates their supergene nature. The main ore minerals includes cryptomelane, lithiophorite, purolusite, hollandite and romanechite associated with impurity components of Ba, Ce, Co, La, Cr, Zn and V.
Journal of African Earth Sciences
The lithostratigraphy of pedogenic manganese (Mn) nodules in the Carletonville area is similar to... more The lithostratigraphy of pedogenic manganese (Mn) nodules in the Carletonville area is similar to the Klipkuil, Ryedale, Wes Wits, and Houtkoppies deposits in the West Rand region of the Gauteng and North West Provinces and to a lesser extent the Bronkhorstfontein manganese deposit in the Limpopo Province of South Africa. The lithostratigraphy of the ore deposit at the General Nice Manganese Mine consists of a basal manganese wad, preserved in a typical karst setting on top of the underlying Malmani stromatolitic dolomites and Tertiary fluvial and secondary mineral deposits consisting of manganese nodules of variable size in a finer-grained soil matrix. At the top of the deposit is a Mn-depleted Quaternary sand cover. The Tertiary alluvial succession hosting Mn nodules was informally subdivided into A, B, C, D, E, F, G and H zones on the basis of geochemical analyses (XRD, XRF and SEM) of bulk zone samples and the manganese nodule size and concentration.
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Papers by Benedict Pharoe