Os data for chromite separates from 10 massive chromitite seams sampled along the 550. Links have also been established between the gold mines of zimbabwe and the indian goldfields of kolar and mysore by the historian roger summers. Most of the primary field work was carried out in november. Platinumgroup minerals in the selukwe subchamber, great dyke. The 2011 production from the msz of the great dyke 340 000 oz. Crystallization, layering, and cumulate formation in the p1 pyroxenite of cyclic unit 1 of the darwendale subchamber allan h. Magnetic fabric in the umvimeela dyke, satellite of the.
The great dyke is one of the most remarkable geological features known. The source of the great dyke, zimbabwe, and its tectonic significance. Zimasco company has mined ferrochrome on the great dyke since the early 1900s and has been owned by local businesses, union carbide corp. Great dyke a body intruding nearly the whole ns length of the zimbabwe craton marks the boundary between the archaean and proterozoic in zimbabwe. The wedzamimosa platinum deposit, great dyke, zimbabwe. Dyke has been geographically subdivided into north, middle and south dyke has approx. Pdf platinumgroup element mineralisation in the great dyke. The dyke or dike in american english intrudes through the even older rocks of african craton, the core of oldest rocks forming the continent of africa. The dyke lies within the zimbabwe craton and has been dated at 2.
In magmatic sulphides the zimbabwe volume eds prendergast, m. Salene has been awarded three special grants under the zimbabwe mines and minerals act covering an area of approximately 9 500 hectares 95km2 on. The source of the great dyke, zimbabwe, and its tectonic. Construction on the city began in the 11th century and continued until it. The main platinumgroup element pge occurrence in the great dyke of zimbabwe, the main sulfide zone msz, is a tabular stratabound layer hosted in pyroxenites. The great dyke of zimbabwe is a layered intrusion of igneous, metalbearing rock that has been dated to approximately 2. Zimbabwe, officially republic of zimbabwe, formerly 191164 southern rhodesia, 196479 rhodesia, or 197980 zimbabwe rhodesia, landlocked country of southern africa. Great zimbabwe were of african origin and not constructed by people from another continent. Great zimbabwe is a ruined city in the southeastern hills of zimbabwe near lake mutirikwe and the town of masvingo. The great dyke in the southern zimbabwe craton is one of the most remarkable rock formations in the world. The great dyke is a linear geological feature stretching from the northsouth through the centre of zimbabwe. Aspects of the population biology, life history and. The great dyke of zimbabwe is unique among large layered intrusions in its extreme length to width ratio, but at the same time shows clearly that differences in the size and positions within individual subchambers can pro foundly affect configurations and styles of layering, textures, and mineral compositions. The hills become taller as the range goes north, and reach up to 460 metres above the mvurwi range.
It consists of a band of short, narrow ridges and hills spanning for approximately 550 kilometres 340 mi. Platinumgroup minerals in the selukwe subchamber, great. Great zimbabwe is the largest of about 250 similarly dated mortarless stone structures in africa, called collectively zimbabwe culture sites. Darwendale deposit is a part of the great dyke in the republic of zimbabwe, one of the worlds largest systems of pgm mineralization with. Elsevier tectonophysics 242 1995 241254 tectonophysics magnetic fabric in the umvimeela dyke, satellite of the great dyke, zimbabwe m. Map showing the location of the magma chambers and subchambers of the great dyke of zimbabwe, and location of the study area after prendergast and wilson, 1989.
They are altered in situ to platinumgroup element pge. It shares a 125mile 200kilometre border on the south with the republic of south africa and is bounded on the southwest and west by botswana, on the north by zambia, and on the northeast and east by mozambique. Business profile the operating subsidiary operated four underground mines and an open pit mine which supplied ore to three concentrator modules two at ngezi and the third one at selous. This range of initial 187os188os values is only slightly higher than the value for the coeval primitive upper mantle 0. Over five hundred kiolmetres long and rarely more than ten wide, it traverses the archean shield of zimbabwe rhodesia from north to south.
Over five hundred kiolmetres long and rarely more than ten wide, it traverses the. Its coordinates are 1800 s and 30300 e in dms degrees minutes seconds or 18 and 30. The 2010 zimbabwe livelihood zone map and the accompanying profiles were compiled through a combination of primary field work and reference to existing secondary data, in particular the 2004 zimbabwe livelihood zones report. The pge are associated with base metal sulphides in the uppermost pyroxenites of the ultramafic sequence of the great dyke. Consisting of four igneous complexes, they increase in height northward to about 1,500 feet 460 m above the plateau surface in the umvukwe range, west of harare formerly salisbury, the. Construction on the city began in the 11th century and continued until it was abandoned in the 15th century. Wilson department of geology, university of natal, p. A craton is a term geologists use to describe earths oldest continental regions.
The dyke spans 550kms with a width varying from 2kms to a maximum of 11kms. The great dyke is a linear geological feature that trends nearly northsouth through the centre of zimbabwe passing just to the west of the capital, harare. These thick and very hard layers of rock are more than 2 billion years old, and form the cores of most of earths continents. At species level, the country supports an estimated 4,440 vascular plant species, 214 of. The great dyke hosts worldclass reserves of platinum group metals and chrome ore. The oxidized ores of the main sulphide zone, great dyke. Mining speculators invade great dyke the zimbabwe independent.
Great dyke great dyke is a dike class s spot feature in zimbabwe general, zimbabwe africa with the region font code of africamiddle east. The grade and thickness of ore bodies persist over large areas. Os isotopes article pdf available in the journal of geology 1115 september 2003 with 1,732 reads. The longest linear mass of mafic and ultramafic rocks in the world, the great dyke bisects the country from north to south and contains enormous reserves. Most of zimbabwes ferrochrome deposits lie in the great dyke, a mountain range that runs the length of the country, rich in ferrochrome, platinum and gold deposits. Great zimbabwe is a massive african iron age settlement and drystone monument located near the town of masvingo in central zimbabwe. Zimbabwe platinum mines private limited, which is a significant producer of pgms, exploiting the ore bodies located on the great dyke in zimbabwe. South africa contains the largest deposits of chromite. This range of initial 187 os 188 os values is only slightly higher than the value for the coeval.
The chromite deposits of the great dyke rhodesia zimbabwe. The bulk of the resource is on the great dyke which hosts about 2. Crystallization, layering, and cumulate formation in the p1. Nearsurface oxidized msz ores have a large potential. However, os isotope data on pregreat dyke ultramafic complexes of the zimbabwe craton and thermal modeling show that such an sclm existed below the zimbabwe craton at the time of the great dyke. A petrographic and silicate composition study across the msz at unki mine in the shurugwi subchamber was conducted to help place some constrains on the origin of the mineralization. Great dyke greatdyke map, weather and photos zimbabwe. Halogen geochemistry of the great dyke, zimbabwe article pdf available in contributions to mineralogy and petrology 1223. Great dyke 0 50 krn i mafic sequence ultramafic sequen i fault o townvillage o ddhi82 selukwe subchamber south chamber wedza subchamber fro.
Great dyke minerals are also mined by thousands of small scale miners and illegal artisanal miners. It consists of a band of short, narrow ridges and hills spanning for approximately 550 kilometres. The great dyke of zimbabwe is unique within the family of large layered intrusions by virtue of its highly elongate form. This paper presents the results of microprobe investigations of the platinumgroup elements pge of the selukwe subchamber, great dyke, zimbabwe.
Pdf platinum and palladium oxideshydroxides from the. Mushayandebvu department of physics, university of zimbabwe, po box mpi6z mount pleasant, harare, zimbabwe received 4 august 1993. Zimbabwe and south africa have 80% of the worlds chrome reserves. Welcome to the presymposium excursion to the great dyke of zimbabwe. It is linear in shape and trends over 550 km nne at a maximum width of about 11 km, and cuts archean granites and greenstone belts of the zimbabwe craton figure 1. Distribution of pge and pgm in oxidized ores of the main. Zimasco company has mined ferrochrome on the great dyke since the early 1900s and has been owned by local businesses, union. The great dyke region is known to contain illuvial chrome concentrations of up to 30% cr2o3 at surface, tharisa said. Pdf reos data for chromite separates from 10 massive chromitite seams sampled along the 550km length of the 2.
The dynamic interplay of crystallization and magma emplacement gave rise to the succession of cyclic units within the ultramafic sequence. Zimbabwe is endowed with a rich diversity of life forms. Platinum and palladium oxideshydroxides from the great dyke. It was the capital of the kingdom of zimbabwe during the countrys late iron age. The great dyke is a linear intrusion of mafic and ultramafic rocks, which cuts across the archaean granites, and greenstones of the zimbabwe craton. The great dyke of zimbabwe is a very elongated maficultramafic layered igneous complex wilson and prendergast 1989, approximately 550 km long. A large literature on the great dyke has accumulated since tbe first paper \\1itten in 1915. The range is host to vast ore deposits, including gold, silver, chromium, platinum, nickel and asbestos. Textural and mineral chemistry data for the ultramafic sequence of the hartley complex are presented with the object of evaluating emplacement mechanisms, crystallization history and subsolidus reequilibration processes for the great dyke. Pdf the origin and petrogenesis of the ultramafic enclaves. The great dyke is a linear geological feature that trends nearly northsouth through the centre.
Apart from the tectonic controls that gave rise to the series of linked magma chambers which together comprise this intrusion, the width to length ratio profoundly affected the layering style, rocktypes, mineral compositions and the form of mineralized ore bodies. Ga great dyke layered igneous complex, zimbabwe, record initial 187os188os ratios in the relatively narrow range between 0. The origin and petrogenesis of the ultramafic enclaves at unki mine, selukwe subchamber, great dyke, zimbabwe sinikiwe ncube a dissertation submitted to the faculty of science, university of witwatersrand in the fulfillment of the requirements for the degree of master of science johannesburg august, 20. Great dyke, narrow series of long, low ridges and hills in zimbabwe, trending for about 320 miles 515 km. The zimbabwe vulnerability assessment committee zimvac would like to express its appreciation for the financial, technical and logistical support that the following agencies provided towards the data collection, analysis and writingup of the revised livelihoods profiles for zimbabwe. Pdf the source of the great dyke, zimbabwe, and its tectonic. Pdf halogen geochemistry of the great dyke, zimbabwe. Zimbabwe has a rich and diverse minerals resource base that could be and should be an important contributor to sustainable growth and development. The company said the great dyke of zimbabwe contains the worlds largest known platinum group metals and highgrade chrome deposits outside of south africa. It shares a 125mile 200km border on the south with the republic of south africa and is bounded on the southwest and west by botswana, on the north by zambia, and on the northeast and east by mozambique. May 24, 2018 the company said the great dyke of zimbabwe contains the worlds largest known platinum group metals and highgrade chrome deposits outside of south africa. Stratigraphically, the layered series of the great dyke is divided into a lower. Mineralogical profiles through the platinumbearing msz layer in weathered trench exposures show that some primary platinumgroup minerals pgm are unstable in the supergene environment.
Stratigraphically, the layered series of the great dyke is divided into a lower ultramafic sequence and an upper mafic sequence. Preface welcome to the presymposium excursion to the great dyke of zimbabwe. Darwendale integrated platinum group metals pgm project is operated by great dyke investments pvt ltd, a joint venture established on a 5050 basis between russian ao afromet and the zimbabwean company. At species level, the country supports an estimated 4,440 vascular plant species, 214 of which are endemic, 672 bird species, 450 of which. Platinumgroup element mineralisation in the great dyke, zimbabwe, and its relationship to magma evolution and magma chamber structure. Platinumgroup element mineralisation in the great dyke. Pdf platinumgroup minerals in the selukwe subchamber.
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