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A description is presented of the Pietersburg and Pilgrim's Rest goldfields and other early discoveries along the Transvaal Drakensberg escarpment in South Africa. The history of gold discoveries in the Archaean volcano-sedimentary successions of the Barberton greenstone belt is discussed including photographs of early mining activities. The total production of gold in the Barberton goldfield since its inception in 1884 is estimated to have been 360 t with most in recent years coming from five mines: Sheba, New Consort, Fairview, Agnes and Lily. Other mineral discoveries in the Barberton greenstone belt are described, among them significant deposits of chrysotile asbestos, iron ore, magnesite, talc and barite together with occurrences of semi-precious commodities (verdite, buddstone, copper-nickel, antimony, mercury, tin-tungsten and zinc)., A description is presented of the Pietersburg and Pilgrim's Rest goldfields and other early discoveries along the Transvaal Drakensberg escarpment in South Africa. The history of gold discoveries in the Archaean volcano-sedimentary successions of the Barberton greenstone belt is discussed including photographs of early mining activities. The total production of gold in the Barberton goldfield since its inception in 1884 is estimated to have been 360 t with most in recent years coming from five mines: Sheba, New Consort, Fairview, Agnes and Lily. Other mineral discoveries in the Barberton greenstone belt are described, among them significant deposits of chrysotile asbestos, iron ore, magnesite, talc and barite together with occurrences of semi-precious commodities (verdite, buddstone, copper-nickel, antimony, mercury, tin-tungsten and zinc).

The Madibe greenstone belt is the easternmost belt of the northern Kraaipan terrane, located in the Kimberley Block of the Kaapvaal Craton. It comprises a mature Middle to Late Archaean volcanic island arc succession that was welded onto the evolving western margin of the Kaapvaal Shield. The lithologies strike in a north-south direction and represent an assemblage of metamorphosed and strongly deformed volcanic and minor sedimentary rocks, now represented by phyllites, quartz-sericite schists, quartz-chlorite schists, amphibolites, talc-carbonate schists and banded iron formations. We report a SHRIMP U-Pb age of 3082.5 ± 5.9 Ma for an intermediate metavolcanic rock. Ages of zircon grains within a volcano-sedimentary rock define ages around 3.43, -3.18 and, ∼3.09 Ga and are as young as ∼3.04 Ga, suggesting the presence of older, mature continental crust. Age relationships of rocks from the Madibe greenstone belt and the Murchison greenstone belt suggest that the Kaapvaal Shield apparently experienced an episode of rapid crustal growth at around 3090 Ma along both the northern and western margins.

Evidence for the existence of Neoarchaean greenstone rocks in the western part of the Kaapvaal Craton is provided by ID-TIMS and SHRIMP U-Pb age data on zircons from supracrustal rocks of the Amalia greenstone belt. Although all the units described from the Amalia greenstone belt might not be coeval, an age of 2750.1 ± 4.6 Ma found for two samples appears to be the best estimate for the deposition of this part of the Amalia greenstone belt sequence. These samples also contain younger zircons, the majority of them yielding a 1099 ± 32 Ma upper intercept age. This date of ∼ 1.1 Ga might indicate that these rocks have been affected by the crustal thickening and magmatism event coeval with the peak of metamorphism during the Namaqua orogeny ∼1.1 Ga. These data provide the first evidence for the development of a Neoarchaean greenstone sequence in the western part of the Kaapvaal Craton. They also demonstrate that the Namaqua orogeny affected rocks within the craton itself.

This paper reports new geochronological and metamorphic data from Onverwacht Group greenstone remnants exposed in the granitoid-dominated terrain to the south of the Barberton greenstone belt. The greenstone remnants consist of metamorphosed mafic and ultramafic metavolcanic sequences, with minor sedimentary units that comprise thin chert and banded iron formation layers, interbanded with the (ultra) mafic volcanic units, as well as an up to 8 m-thick clastic sedimentary unit that contains well-preserved primary sedimentary features such as trough cross-bedding. Coarse-grained portions of the clastic sediments contain up to 4.5 wt.% K2O and represent metamorphosed impure arkoses. SHRIMP and conventional U-Pb dating of detrital zircons reveal dates ranging between ca. 3521 and 3540 Ma, indicating that at least two protoliths for these sediments predate the formation of the bulk of the Barberton greenstone belt. A minimum age of 3431 ± 11 Ma for the formation of the metasediments is given by a trondhjemite gneiss that intrudes the greenstone remnant. Thus, these metasediments were deposited between ca. 3521 and 3431 Ma, contemporaneously with the erosion of spacially associated older, and presumably potassium-rich, granitoid rocks. Other portions of the clastic metasediments have a mafic affinity and are characterised by the peak-metamorphic mineral assemblage diopside + andesine + garnet + quartz. This assemblage, and garnet in particular, is extensively replaced by epidote. Peak-metamorphic mineral assemblages of magnesio - hornblende + andesine + quartz, and quartz + ferrosilite + magnetite + grunerite have been recorded from adjacent amphibolites and interlayered iron formation units, respectively. In these rocks, retrogression is marked by actinolitic rims around peak metamorphic magnesio-hornblende cores in the metamafic rocks, and by a second generation of grunerite that occurs as fibrous aggregates rimming orthopyroxene in the iron formation. PT calculations

The Schapenburg Schist Belt is one of several large greenstone remnants exposed in the granitoid-dominated terrane to the south of the Barberton greenstone belt and is unique in that it contains a well-developed metasedimetary sequence in addition to the

Topics covered by the 178 theses listed include the geology, genesis, structure and process mineralogy of particular South African deposits and those of neighbouring and a few overseas states, local and tropical exploration methods, a number of aspects of pollution and environmental protection, and South African water resources. The entries are arranged alphabetically by author and by university, and there is also a list of pre-1994 theses omitted from an earlier publication and of errata., Topics covered by the 178 theses listed include the geology, genesis, structure and process mineralogy of particular South African deposits and those of neighbouring and a few overseas states, local and tropical exploration methods, a number of aspects of pollution and environmental protection, and South African water resources. The entries are arranged alphabetically by author and by university, and there is also a list of pre-1994 theses omitted from an earlier publication and of errata.

Introductory chapters are presented on the economic geology of South Africa, the South African minerals industry, legislative and environmental aspects of mining, mineral processing and extractive metallurgy, and resource and reserve classification. Commodity chapters are included which give an overview of each commodity, its chemical constituents, physical properties, uses and applications. Current trends of production and consumption, both locally and internationally, are considered. Where appropriate a section is presented on the genesis or classification of deposit types, with the more important deposits and occurrences being discussed on a province-by-province basis. Commodities discussed are: aggregates, aluminium, andalusite, antimony, arsenic, asbestos, barite, beryllium, bismuth, brick making materials, chromium, clay, coal, cobalt, copper, corundum, diamonds, dimension stone, feldspar, fluorspar, garnet, gemstones, gold, graphite, gypsum, helium, iron, kieselguhr (diatomite), lead, limestone and dolomite, lithium, magnesite, manganese, mercury, mica, molybdenum, nickel, oil and gas, other carbonaceous fuels, peat, pegmatite, perlite, phosphate, platinum group metals, rare earth elements, road construction materials, salt, silicon and silica, silver, soda, sulphur and pyrite, talc and pyrophyllite, tantalum and niobium, thorium, tin, titanium, tungsten, uranium, vanadium, vermiculite and phlogopite, wollastonite, zeolite minerals, zinc, and zirconium and hafnium. Each chapter has a list of references and there is a subject/deposit index., Introductory chapters are presented on the economic geology of South Africa, the South African minerals industry, legislative and environmental aspects of mining, mineral processing and extractive metallurgy, and resource and reserve classification. Commodity chapters are included which give an overview of each commodity, its chemical constituents, physical properties, uses and applications. Current trends of production and consumption, both locally and internationally, are considered. Where appropriate a section is presented on the genesis or classification of deposit types, with the more important deposits and occurrences being discussed on a province-by-province basis. Commodities discussed are: aggregates, aluminium, andalusite, antimony, arsenic, asbestos, barite, beryllium, bismuth, brick making materials, chromium, clay, coal, cobalt, copper, corundum, diamonds, dimension stone, feldspar, fluorspar, garnet, gemstones, gold, graphite, gypsum, helium, iron, kieselguhr (diatomite), lead, limestone and dolomite, lithium, magnesite, manganese, mercury, mica, molybdenum, nickel, oil and gas, other carbonaceous fuels, peat, pegmatite, perlite, phosphate, platinum group metals, rare earth elements, road construction materials, salt, silicon and silica, silver, soda, sulphur and pyrite, talc and pyrophyllite, tantalum and niobium, thorium, tin, titanium, tungsten, uranium, vanadium, vermiculite and phlogopite, wollastonite, zeolite minerals, zinc, and zirconium and hafnium. Each chapter has a list of references and there is a subject/deposit index.

References are presented relating to the geology and mineral deposits of the Barberton greenstone belt and surrounding areas of eastern Mpumalanga Province (formerly the Eastern Transvaal Lowveld) and Swaziland. Over 250 references are given arranged alphabetically by author., References are presented relating to the geology and mineral deposits of the Barberton greenstone belt and surrounding areas of eastern Mpumalanga Province (formerly the Eastern Transvaal Lowveld) and Swaziland. Over 250 references are given arranged alphabetically by author.

The modern techniques needed for the identification of ore resources and their effective management are highlighted. Remote exploration methods are included which, although standard practice today, were at the forefront of technology when the reefs on the Far West Rand were discovered. The processing of vast quantities of data is a feature of modern exploration. Ore reserve estimation requires professionally applied techniques and remains one of the highest risks in new mining projects. The best possible understanding of the deposition of an ore resource, including intrusive facies, sedimentary patterns and structural controls is necessary for accurate resource estimation and mine planning. Certainly sedimentology is one of the real challenges in deep South African gold mines. Effective modelling of the complex shapes and patterns of orebodies is difficult to achieve but yields substantial benefits in the control of mineral operations, especially in ore grade control. Attention is given to careful planning for exploitation at depth and for marginal operations, and to the optimal extraction of coal and industrial minerals. These individual technical aspects are complemented by case studies on the one hand and by broad review papers on the other, in sections on the Witwatersrand basin, Witwatersrand case histories and orebody modelling, coal case histories, platinum case histories, general topics, base metals exploration and case histories, geophysics and the Vibroseis technique, and geophysics and mine planning., The modern techniques needed for the identification of ore resources and their effective management are highlighted. Remote exploration methods are included which, although standard practice today, were at the forefront of technology when the reefs on the Far West Rand were discovered. The processing of vast quantities of data is a feature of modern exploration. Ore reserve estimation requires professionally applied techniques and remains one of the highest risks in new mining projects. The best possible understanding of the deposition of an ore resource, including intrusive facies, sedimentary patterns and structural controls is necessary for accurate resource estimation and mine planning. Certainly sedimentology is one of the real challenges in deep South African gold mines. Effective modelling of the complex shapes and patterns of orebodies is difficult to achieve but yields substantial benefits in the control of mineral operations, especially in ore grade control. Attention is given to careful planning for exploitation at depth and for marginal operations, and to the optimal extraction of coal and industrial minerals. These individual technical aspects are complemented by case studies on the one hand and by broad review papers on the other, in sections on the Witwatersrand basin, Witwatersrand case histories and orebody modelling, coal case histories, platinum case histories, general topics, base metals exploration and case histories, geophysics and the Vibroseis technique, and geophysics and mine planning.

Southern Africa offers a unique insight into many aspects of Precambrian geology, crustal evolution and metallogeny. Episodic introduction of granitic magmas assisted in the destruction of extensive volcanic or greenstone terranes. This process, involving cratonisation, led to the creation of microcontinental masses (such as the Rhodesian and Kaapvaal crustal fragments) and high metamorphic grade structural provinces (such as the Limpopo Belt straddling the Zimbabwe-South African border). Intracratonic volcanism and sedimentation began during the Late Archaean and led to the sequential development of interior basins which increased in size from 3000 Ma to 1800 Ma. The metallogeny of southern Africa is interwoven with the stages of crustal evolution and continental development. Mineralisation is linked to metallogenic provinces and is also shown to be genetically related to host rock evolution and the superimposed influence of igneous intrusion, metamorphism and structural disturbance. The resources of the region are highlighted and reserves data is presented., Southern Africa offers a unique insight into many aspects of Precambrian geology, crustal evolution and metallogeny. Episodic introduction of granitic magmas assisted in the destruction of extensive volcanic or greenstone terranes. This process, involving cratonisation, led to the creation of microcontinental masses (such as the Rhodesian and Kaapvaal crustal fragments) and high metamorphic grade structural provinces (such as the Limpopo Belt straddling the Zimbabwe-South African border). Intracratonic volcanism and sedimentation began during the Late Archaean and led to the sequential development of interior basins which increased in size from 3000 Ma to 1800 Ma. The metallogeny of southern Africa is interwoven with the stages of crustal evolution and continental development. Mineralisation is linked to metallogenic provinces and is also shown to be genetically related to host rock evolution and the superimposed influence of igneous intrusion, metamorphism and structural disturbance. The resources of the region are highlighted and reserves data is presented.

Although most of the references relate to the geology of the predominantly Archaean terrane exposed to the east of the Transvaal Drakensberg escarpment, the work also includes in its scope some references to historical aspects of the area as well as to reports of evidence pertaining to the origin and evolution of primitive life forms. Also included are some references, not directly relating to the Barberton Mountain Land or its surroundings, but which merely refer to the area for comparative reasons. The list is arranged alphabetically according to author., Although most of the references relate to the geology of the predominantly Archaean terrane exposed to the east of the Transvaal Drakensberg escarpment, the work also includes in its scope some references to historical aspects of the area as well as to reports of evidence pertaining to the origin and evolution of primitive life forms. Also included are some references, not directly relating to the Barberton Mountain Land or its surroundings, but which merely refer to the area for comparative reasons. The list is arranged alphabetically according to author.

The theme of the congress was "Resources and technology". The intention was to highlight the importance of basic technical operations in the achievement of safe, healthy and competitive mineral production, effective management of resources, respect for the workers' environment and attention to the needs of all sponsors. Some 70% of the papers presented describe the South African industry, which is characterised by steadily deepening gold mines and by a wide diversity of mineral operations, many of world-class proportions. These papers are complemented by a range dealing with international topics., The theme of the congress was "Resources and technology". The intention was to highlight the importance of basic technical operations in the achievement of safe, healthy and competitive mineral production, effective management of resources, respect for the workers' environment and attention to the needs of all sponsors. Some 70% of the papers presented describe the South African industry, which is characterised by steadily deepening gold mines and by a wide diversity of mineral operations, many of world-class proportions. These papers are complemented by a range dealing with international topics.

Volume 1 contains 79 papers as well as an explanation of the revised map of the Witwatersrand Basin scale 1:500 000. Two introductory papers are followed by 36 papers describing various Archaean mineral deposits which include gold, nickel, copper, antimony, and chrysotile asbestos. The 17 papers dealing with early Proterozoic deposits cover gold and uranium mines of the gold fields within the Witwatersrand Basin. 23 papers dealing with the middle Proterozoic mineral deposits describe fluorspar, lead, zinc, amosite/crocidolite asbestos, iron, manganese and andalusite occurrences. Volume 2 contains 100 papers including an explanation of the new geological/mineral occurrences map of Southern Africa scale 1:4 000 000. This volume commences with 25 papers dealing with aspects of the platinum, chromite, vanadiferous/titaniferous magnetite, tin and fluorspar deposits hosted by, or associated with, the unique Bushveld Complex. This is followed by a review of the middle Proterozoic Lomagundi and Sabi metallogenic provinces of Zimbabwe. Descriptions of base mineral deposits from various metamorphic mobile belts in Southern Africa are included in 22 papers. Later Proterozoic mineral deposits from South West Africa/Namibia, including many which are hosted in the Damara Orogen, are described in a series of 11 papers. The Phanerozoic deposits of the Karoo Sequence, which include the major coalfields of Southern Africa, are discussed in 29 papers, followed by 7 papers describing mineralisation associated with carbonatites and alkaline rocks, including kimberlites. The final 4 papers discuss mineral occurrences extending through to recent times including present-day surficial deposits., Volume 1 contains 79 papers as well as an explanation of the revised map of the Witwatersrand Basin scale 1:500 000. Two introductory papers are followed by 36 papers describing various Archaean mineral deposits which include gold, nickel, copper, antimony, and chrysotile asbestos. The 17 papers dealing with early Proterozoic deposits cover gold and uranium mines of the gold fields within the Witwatersrand Basin. 23 papers dealing with the middle Proterozoic mineral deposits describe fluorspar, lead, zinc, amosite/crocidolite asbestos, iron, manganese and andalusite occurrences. Volume 2 contains 100 papers including an explanation of the new geological/mineral occurrences map of Southern Africa scale 1:4 000 000. This volume commences with 25 papers dealing with aspects of the platinum, chromite, vanadiferous/titaniferous magnetite, tin and fluorspar deposits hosted by, or associated with, the unique Bushveld Complex. This is followed by a review of the middle Proterozoic Lomagundi and Sabi metallogenic provinces of Zimbabwe. Descriptions of base mineral deposits from various metamorphic mobile belts in Southern Africa are included in 22 papers. Later Proterozoic mineral deposits from South West Africa/Namibia, including many which are hosted in the Damara Orogen, are described in a series of 11 papers. The Phanerozoic deposits of the Karoo Sequence, which include the major coalfields of Southern Africa, are discussed in 29 papers, followed by 7 papers describing mineralisation associated with carbonatites and alkaline rocks, including kimberlites. The final 4 papers discuss mineral occurrences extending through to recent times including present-day surficial deposits.

The granitoids have been subdivided into three categories, termed magmatic cycles. Each magmatic cycle is considered to have evolved progressively through time by reworking of pre-existing crustal material. The U and Th contents increase progressively from the first magmatic cycle to the third magmatic cycle. Comparison of U, Th, Zr, and Ce contents indicates that the mineralogical siting of U and Th may differ from one magmatic cycle to the other. There are also indications that some granitic bodies are relatively enriched in U whereas others appear to have suffered U loss., The granitoids have been subdivided into three categories, termed magmatic cycles. Each magmatic cycle is considered to have evolved progressively through time by reworking of pre-existing crustal material. The U and Th contents increase progressively from the first magmatic cycle to the third magmatic cycle. Comparison of U, Th, Zr, and Ce contents indicates that the mineralogical siting of U and Th may differ from one magmatic cycle to the other. There are also indications that some granitic bodies are relatively enriched in U whereas others appear to have suffered U loss.

The Muldersdrif Ultramafic Complex is located in an Archaean greenstone remnant situated on the western edge of the Johannesburg granite dome. The layered igneous body, which consists of cyclically repetitive units of serpentinised dunited, harzburgites and pyroxentes, together with metagabbroic rocks, is similar to many of the apparently unique layered ultramafic complexes found in the Lower Ultramafic Unit in the Barberton Mountain Land., The Muldersdrif Ultramafic Complex is located in an Archaean greenstone remnant situated on the western edge of the Johannesburg granite dome. The layered igneous body, which consists of cyclically repetitive units of serpentinised dunited, harzburgites and pyroxentes, together with metagabbroic rocks, is similar to many of the apparently unique layered ultramafic complexes found in the Lower Ultramafic Unit in the Barberton Mountain Land.

The earliest rocks, represented by high-grade gneiss terrains, contain little evidence of mineralisation; either it is destroyed by later events or no significant concentrations of metals arose. The period from 3500 to 2500 my is characterised by granite-greenstone terrains of the shield areas. The greenstone sequences are divided into basal mafic-ultramafic units, followed by mafic to felsic volcanic sequences, overlain by rocks of sedimentary origin. The mineralisation associated with these rock types and with the granitic rocks is described. The evolution of rock type and tectonic style with time is considered; the closest analogy with modern environments for greenstone belts is to island arc-marginal basin settings, though vertical tectonics were more important. Archaean mineral deposits are essentially secondary in origin, having formed as a result of superimposed magmatic, metamorphic, structural and alteration processes., The earliest rocks, represented by high-grade gneiss terrains, contain little evidence of mineralisation; either it is destroyed by later events or no significant concentrations of metals arose. The period from 3500 to 2500 my is characterised by granite-greenstone terrains of the shield areas. The greenstone sequences are divided into basal mafic-ultramafic units, followed by mafic to felsic volcanic sequences, overlain by rocks of sedimentary origin. The mineralisation associated with these rock types and with the granitic rocks is described. The evolution of rock type and tectonic style with time is considered; the closest analogy with modern environments for greenstone belts is to island arc-marginal basin settings, though vertical tectonics were more important. Archaean mineral deposits are essentially secondary in origin, having formed as a result of superimposed magmatic, metamorphic, structural and alteration processes.

A sequence dominated by metamorphosed Archaean komatiitic basalts and komatiites makes up most of the Nelshoogte schist belt area. These rocks may be significantly younger than previously thought, c.3250 Ma rather than c.3500 Ma. The comparison of mafic and ultramafic rocks of the area with Phanerozoic ophiolites is considered untenable. Plutons adjacent to the metavolcanic rocks date from around 3236-3213 Ma. The fault-bounded sequence of metamorphosed mafic-ultramafic cumulates that make up the Stolzburg layered complex has lower serpentinised dunites and orthopyroxenites and upper altered dunites, harzburgites, lherzolites, wehrlites, websterites, gabbro-norites and anorthositic gabbros. Three chrysotile asbestos deposits were mined in the complex, there are minor gold and copper-nickel occurrences in the schist belt and potential for platinum group metals is thought good., A sequence dominated by metamorphosed Archaean komatiitic basalts and komatiites makes up most of the Nelshoogte schist belt area. These rocks may be significantly younger than previously thought, c.3250 Ma rather than c.3500 Ma. The comparison of mafic and ultramafic rocks of the area with Phanerozoic ophiolites is considered untenable. Plutons adjacent to the metavolcanic rocks date from around 3236-3213 Ma. The fault-bounded sequence of metamorphosed mafic-ultramafic cumulates that make up the Stolzburg layered complex has lower serpentinised dunites and orthopyroxenites and upper altered dunites, harzburgites, lherzolites, wehrlites, websterites, gabbro-norites and anorthositic gabbros. Three chrysotile asbestos deposits were mined in the complex, there are minor gold and copper-nickel occurrences in the schist belt and potential for platinum group metals is thought good.

The fragments of gneiss in a granite matrix represent voluminous, structurally controlled, pipe-like migmatites formed by varied melt segregation processes during high-grade metamorphism, regional melting and coeval deformation. The close relationship between the megabreccias and narrow, high-strain steep structures indicates positive feed-back between deformation and melting. Melting was promoted by strain incompatibilities and enhanced permeabilities in the steep structures, which then provided an upright network for melt migration. Vertical transport of fragments for up to 700 m indicates the existence open, vertical, interconnected conduits at mid-crustal levels; the absence of megabreccias from the high-grade terrain to the south underscores the significance of deformation. The basic bodies of the Koperberg Suite were emplaced into low-pressure sites and propagated along hydraulic gradients in the steep structures., The fragments of gneiss in a granite matrix represent voluminous, structurally controlled, pipe-like migmatites formed by varied melt segregation processes during high-grade metamorphism, regional melting and coeval deformation. The close relationship between the megabreccias and narrow, high-strain steep structures indicates positive feed-back between deformation and melting. Melting was promoted by strain incompatibilities and enhanced permeabilities in the steep structures, which then provided an upright network for melt migration. Vertical transport of fragments for up to 700 m indicates the existence open, vertical, interconnected conduits at mid-crustal levels; the absence of megabreccias from the high-grade terrain to the south underscores the significance of deformation. The basic bodies of the Koperberg Suite were emplaced into low-pressure sites and propagated along hydraulic gradients in the steep structures.

The ENE-trending Murchison greenstone belt, Transvaal, is a narrow, isoclinally folded sequence of deformed metavolcanic and metasedimentary rocks intruded by Archaean granites and gneisses. U-Pb dating has provided evidence for the development of the greenstone belt that is substantially younger than previously suggested. A discrete episode of greenstone belt formation has been identified along with associated gold mineralisation. The age range of the Murchison belt (3.07-2.97 Ga) has been shown to overlap with that of the Witwatersrand basin and it is suggested that the events that gave rise to the volcano-sedimentary successions were of major importance as a potential source of placer gold., The ENE-trending Murchison greenstone belt, Transvaal, is a narrow, isoclinally folded sequence of deformed metavolcanic and metasedimentary rocks intruded by Archaean granites and gneisses. U-Pb dating has provided evidence for the development of the greenstone belt that is substantially younger than previously suggested. A discrete episode of greenstone belt formation has been identified along with associated gold mineralisation. The age range of the Murchison belt (3.07-2.97 Ga) has been shown to overlap with that of the Witwatersrand basin and it is suggested that the events that gave rise to the volcano-sedimentary successions were of major importance as a potential source of placer gold.

New evidence is presented on the Koperberg Suite intrusions in the Proterozoic gneisses and granites of the Okiep copper district which illustrates the intrusive nature of the basic bodies and various modes of occurrence, emplacement and propagation of mafic magmas in a segment of middle to lower crust. It is demonstrated that the geometry of the intrusions is the product of the interaction and interdependence between coaeval high-grade metamorphism, ductile deformation and the intrusion of the basic magmas., New evidence is presented on the Koperberg Suite intrusions in the Proterozoic gneisses and granites of the Okiep copper district which illustrates the intrusive nature of the basic bodies and various modes of occurrence, emplacement and propagation of mafic magmas in a segment of middle to lower crust. It is demonstrated that the geometry of the intrusions is the product of the interaction and interdependence between coaeval high-grade metamorphism, ductile deformation and the intrusion of the basic magmas.

The Steynsdorp anticline in the Barberton greenstone belt forms a prominent, upright, northerly trending fold structure developed in greenstone lithologies of the Onverwacht Group and is cored by tonalitic gneisses in the Steynsdorp pluton. Different fold geometries within the anticline, superimposed strains and the orientation and interference of linear and planar fabrics suggest the doming of an older, gneissic basement of the pluton during regional WNW-ESE crustal shortening. The portrayal of an older gneissic core of the pluton, which is conformably overlain by younger metamorphic supracrustals, is in accord with the classical description of a mantled gneiss dome. The geometric and structural evidence suggest that the Steynsdorp pluton should in future be referred to as the Steynsdorp dome. The synkinematism between regional folding and local gneiss is believed to have played an important role in the localisation of gold mineralisation in the region known as the Steynsdorp Goldfield., The Steynsdorp anticline in the Barberton greenstone belt forms a prominent, upright, northerly trending fold structure developed in greenstone lithologies of the Onverwacht Group and is cored by tonalitic gneisses in the Steynsdorp pluton. Different fold geometries within the anticline, superimposed strains and the orientation and interference of linear and planar fabrics suggest the doming of an older, gneissic basement of the pluton during regional WNW-ESE crustal shortening. The portrayal of an older gneissic core of the pluton, which is conformably overlain by younger metamorphic supracrustals, is in accord with the classical description of a mantled gneiss dome. The geometric and structural evidence suggest that the Steynsdorp pluton should in future be referred to as the Steynsdorp dome. The synkinematism between regional folding and local gneiss is believed to have played an important role in the localisation of gold mineralisation in the region known as the Steynsdorp Goldfield.