Council for Geoscience

Bellville, South Africa

Council for Geoscience

Bellville, South Africa

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Grant
Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: ENV.2007.4.1.4.1. | Award Amount: 2.42M | Year: 2008

Africa, the largest single component of the African Caribbean Pacific (ACP) Group of States, despite its huge potential for development through both human and georesources, suffers in many places from poverty and underdevelopment. The sustainable use of its resources is a key issue, not only for development of the African countries, but also for the worlds future. Over the coming decades, these issues are likely to play an ever-increasing role due to the worlds growing population, rapid urban development and the rising demand for better infrastructure and services. The sustainable use of georesources requires a knowledge based on data, information and expertise. Thus, the availability, traceability, accessibility and processing using GIS technologies of heterogeneous data from multiple sources is essential. Such processing requires a qualified and experienced personnel and the definition of strategies for capacity building and training. In view of this situation, a recognised need has emerged for a shared, distributed, Internet-linked georesources observation system, based on open standards and interoperability developments, as a contribution to the sustainable development of African countries. The Support Action is the preparatory phase needed to design the African-European Georesource Observation System (AEGOS) capable of hosting and providing access to Africas geological resources, including groundwater, energy, raw materials and mineral resources. Its objectives are to define: i) operational procedures for data management (Spatial Data Infrastructure, metadata and data specification), ii) user-oriented products and services including the preparation of innovative spin off projects based on AEGOS and an evaluation of the input of Interoperability and interdisciplinary in support of GEOSS iii) the African- European partner network, iv) a geoscience contribution to GEOSS, in the context of INSPIRE


Grant
Agency: European Commission | Branch: FP7 | Program: CP-FP-SICA | Phase: ENV.2009.4.1.3.2 | Award Amount: 4.14M | Year: 2010

European Commission Vice President Gnter Verheugen, responsible for enterprise and industry policy declared European industries need predictability in the flow of raw materials and stable prices to remain competitive. We are committed to improve the conditions of access to raw materials, be it within Europe or by creating a level playing field in accessing such materials from abroad. The global dimension of access to raw materials was on the agenda of the G8 Summit on June 2007. On that occasion a Declaration on Responsibility for raw materials: transparency and sustainable growth was adopted. Several national and international initiatives, both from the private or the institutional sectors, arised to address the sustainable development of the extractive industry and the reduction of its environmental footprint. Meanwhile, the extractive industry is facing increasing environmental and societal pressures, being regulatory or not, during all phases of a project, from exploration to exploitation and closure. The social acceptability of a project is among the major key issues to be dealt with. EO-MINERS scientific and technical objectives are to: - assess policy requirements at macro (public) and micro (mining companies) levels and define environmental, socio-economic, societal and sustainable development criteria and indicators to be possibly dealt using EO - use existing EO knowledge and carry out new developments on demonstration sites to further demonstrate the capabilities of integrated EO-based methods and tools in monitoring, managing and contributing reducing the environmental and societal footprints of the extractive industry during all phases of a mining project, from the exploration to the exploitation and closure stages - contribute making available reliable and objective information about affected ecosystems, populations and societies, to serve as a basis for a sound trialogue between industrialists, governmental organisations and stakeholder


Yates A.M.,University of Witwatersrand | Bonnan M.F.,Western Illinois University | Neveling J.,Council for Geoscience | Chinsamy A.,University of Cape Town | Blackbeard M.G.,University of Witwatersrand
Proceedings of the Royal Society B: Biological Sciences | Year: 2010

Aardonyx celestae gen. et sp. nov. is described from the upper Elliot Formation (Early Jurassic) of South Africa. It can be diagnosed by autapomorphies of the skull, particularly the jaws, cervical column, forearm and pes. It is found to be the sister group of a clade of obligatory quadrupedal sauropodomorphs (Melanorosaurus + Sauropoda) and thus lies at the heart of the basal sauropodomorph-sauropod transition. The narrow jaws of A. celestae retain a pointed symphysis but appear to have lacked fleshy cheeks. Broad, U-shaped jaws were previously thought to have evolved prior to the loss of gape-restricting cheeks. However, the narrow jaws of A. celestae retain a pointed symphysis but appear to have lacked fleshy cheeks, demonstrating unappreciated homoplasy in the evolution of the sauropod bulk-browsing apparatus. The limbs of A. celestae indicate that it retained a habitual bipedal gait although incipient characters associated with the pronation of the manus and the adoption of a quadrupedal gait are evident through geometric morphometric analysis (using thin-plate splines) of the ulna and femur. Cursorial ability appears to have been reduced and the weight bearing axis of the pes shifted to a medial, entaxonic position, falsifying the hypothesis that entaxony evolved in sauropods only after an obligate quadrupedal gait had been adopted. © 2009 The Royal Society.


Roelofse F.,Council for Geoscience | Roelofse F.,University of Witwatersrand | Ashwal L.D.,University of Witwatersrand
Journal of Petrology | Year: 2012

The lower Main Zone (LMZ) in the Northern Limb of the Bushveld Complex as intersected by the 1563·02 m deep Moordkopje (MO-1) drill hole shows very little large-scale differentiation as exemplified by parameters such as the An% of plagioclase, the Mg# of pyroxene and the modified differentiation index over a vertical interval in excess of 1·3 km. These features, coupled with the late entry of pigeonite (now inverted to orthopyroxene), are suggestive of the repeated intrusion of magma into the magma chamber of the Northern Limb during the early stages of the development of the Main Zone. Importantly, the lower Main Zone (LMZ) exhibits significant Sr isotopic disequilibrium between coexisting plagioclase (Sr. i ∼0·708) and orthopyroxene (Sr. i up to ∼0·711) in certain samples, a feature that has not previously been described for the Main Zone. Many of the features of the lower Main Zone (e.g. bulk compositions of LMZ cumulates unsuitable for the crystallization of plagioclase + two pyroxenes; poorly developed layering; non-cotectic proportions of plagioclase and pyroxene; decoupling of the differentiation trends of plagioclase and pyroxene over short vertical intervals) in the Northern Limb may be explained if it was intruded not as repeated influxes of aphyric magma, but instead by the repeated intrusion of crystal mushes from a deeper, sub-compartmentalized, crustal staging chamber. The model proposed is an alternative to previous models suggesting the loss of extrusive components from the Bushveld Complex, which were developed to explain compositional paradoxes within the Bushveld Complex. © The Author 2012. Published by Oxford University Press. All rights reserved.


Sadeghi M.,Geological Survey of Sweden | Billay A.,Council for Geoscience | Carranza E.J.M.,James Cook University
Journal of Geochemical Exploration | Year: 2015

Previous exploration activities in the Giyani greenstone belt (GGB) were guided by the availability of outcrops, particularly iron formation, as this rock was considered to be the main host rock for gold mineralisation in the belt, although the majority of the known prospects/deposits are hosted by mafic rocks. However, there is no reliable lithological map available for the GGB, because most of it is covered by regolith, and thus in the early 1990s most mining and exploration companies in the GGB have abandoned their work as they were discouraged by the scarcity of outcrops, the small sizes of existing deposits and the low gold prices at that time. In the present study, major and trace element geochemical data from a high-density soil geochemical survey (1 sample/km2) have been subjected to statistical and spatial analyses to support bedrock mapping and gold exploration. Maps are presented for major oxides, trace elements and selected respective ratio maps, and principal components (PC). The PC analysis was performed on clr-transformed data of selected trace elements known to be associated with gold mineralisation. The first six PCs explain about 78% of the total variance. PC4 representing Sb-As-Te-Cr-Au association best reflects the known gold mineralisation and was, therefore, used as a thematic layer. The information provided by various composite maps of different major/trace element data, as well as PC maps, has been used to produce an interpretive bedrock map outlining major lithological units in the study area. As gold mineralisation in the Giyani greenstone belt is hosted by certain known lithologies, the map is useful in indicating potential gold bearing areas. © 2014 Elsevier B.V.


Hallbauer-Zadorozhnaya V.,Council for Geoscience | Santarato G.,University of Ferrara | Zeid N.A.,University of Ferrara
Geophysical Journal International | Year: 2015

In this paper, two separate but related goals are tackled. The first one is to demonstrate that in some saturated rock textures the non-linear behaviour of induced polarization (IP) and the violation of Ohm's law not only are real phenomena, but they can also be satisfactorily predicted by a suitable physical-mathematical model, which is our second goal. This model is based on Fick's second law. As the model links the specific dependence of resistivity and chargeability of a laboratory sample to the injected current and this in turn to its pore size distribution, it is able to predict pore size distribution from laboratory measurements, in good agreement with mercury injection capillary pressure test results. This fact opens up the possibility for hydrogeophysical applications on a macro scale. Mathematical modelling shows that the chargeability acquired in the field under normal conditions, that is at lowcurrent, will always be very small and approximately proportional to the applied current. A suitable field test site for demonstrating the possible reliance of both resistivity and chargeability on current was selected and a specific measuring strategy was established. Two data sets were acquired using different injected current strengths, while keeping the charging time constant. Observed variations of resistivity and chargeability are in agreement with those predicted by the mathematical model. These field test data should however be considered preliminary. If confirmed by further evidence, these facts may lead to changing the procedure of acquiring field measurements in future, and perhaps may encourage the design and building of a new specific geo-resistivity meter. This paper also shows that the well-known Marshall and Madden's equations based on Fick's law cannot be solved without specific boundary conditions. © The Authors 2015.


Neumann F.H.,University of Munster | Botha G.A.,Council for Geoscience | Scott L.,University of the Free State
Vegetation History and Archaeobotany | Year: 2014

A palynological and sedimentological record from the Mahwaqa Mountain in KwaZulu-Natal, South Africa, provides evidence of the vegetation dynamics in this part of the Grassland Biome during the last c. 18,000 years. The wetland is located at 1,850 m on an isolated outlier of the Ukhahlamba–Drakensberg Mountain range on an ecotone along a climatic gradient. The vegetation responded to humidity and temperature changes during the late Pleistocene and Holocene. The period c. 18,000–13,500 cal. bp is characterized by high Ericaceae and Restionaceae percentages and decreasing values of charred particles, indicating cool conditions. Around 13,500–8,500 cal. bp, Ericaceae were gradually replaced by Poaceae, signaling climate warming. Growing environmental wetness during the same time period is inferred from Phragmites-type and Cliffortia pollen percentages. Since c. 8,500 cal. bp, Cliffortia, Restionaceae, and Phragmites-type percentages have maintained low levels. Ericaceae were almost completely replaced by grasses and Asteraceae by c. 7,500 cal. bp. All indications are that warm and fluctuating moisture conditions followed until 4,600 cal. bp but they became driest between c. 4,600 and 3,500 cal. bp, when high Asteraceae, Pentzia-type and Scabiosa percentages were prominent. From c. 3,500–800 cal. bp, the increase of sedges, Aponogeton and grass pollen (including Phragmites-type) at the expense of Asteraceae pollen suggests the return of slightly more humid conditions. Since c. 1,000 cal. bp an increase of water demanding Podocarpus and Cliffortia occurred. Pine pollen indicates the recent introduction of alien plants in the 19th and 20th centuries. © 2014, Springer-Verlag Berlin Heidelberg.


The Vungu shear zone is one of only two D3 shear zones in the Margate Terrane, and is here named and examined in detail for the first time. Detailed mapping indicates that this ∼10 km wide shear zone can be subdivided into a high-strain core (∼2 to 4 km thick) and lower-strain southeastern and northwestern marginal (each ∼3 to 4 km thick) subzones. Macro- and microstructures are similar to other D3 shear zones in the Natal Metamorphic Province. Part of the northwestern marginal subzone shows D3-parallel magmatic foliation developed in the Oribi Gorge granite, thereby providing a reliable upper age of ∼1.07 to 1.08 Ga for D3 in the Margate Terrane. This upper age is ∼20 to 47 Ma older than that determined for the D3 event in the Mzumbe Terrane. Integration with newly constrained ages of the D1 (∼1.09 Ga) and D2 (1.09 to 1.06 Ga) events illustrate their temporal overlap and support models that propose the D1- D3 structures comprise different expressions of the same tectonic event. © 2010 June Geological Society of South Africa.


Mendonidis P.,Vaal University of Technology | Thomas R.J.,Council for Geoscience | Grantham G.H.,Central Regions Unit | Armstrong R.A.,Australian National University
Precambrian Research | Year: 2015

The Margate Granite Suite underlies much of the Margate Terrane of the Natal Metamorphic Province, SE South Africa. It consists of foliated granites grouped into four main lithotypes: garnet leucogranite, garnet-free leucogranite, charnockite and garnet-biotite augen gneiss. In this study we present new U-Pb (SHRIMP) zircon geochronological data on each of the four lithotypes to constrain the timing of emplacement of the various granite phases and of charnockite formation. Magmatic zircon ages span a period of about 125 Ma, indicating that the Margate Suite does not comprise a single coeval group of plutons. The oldest crystallisation age of 1169 ± 14 Ma, obtained from the garnet-biotite augen gneiss phase, is statistically similar to that of the Sikombe Granite which is exposed to the south of the Margate Terrane, with which a correlation is made. This implies that the magmatic history of the Margate Terrane is longer and more complex than previously thought. The original granite protolith of a sample from the charnockitised granite in the thermal aureole of the (ca. 1040 Ma) Oribi Gorge granite yielded an age of 1135 ± 11 Ma, which is statistically similar to the published age of the gneissic Mzimilo Granite in the Mzumbe Terrane. Zircon overgrowths in this sample, dated at 1037 ± 13Ma are coeval with the age of the Oribi Gorge granite and are interpreted to date the secondary charnockitisation of the Margate granite. A sample of a partly charnockitised garnet leucogranite provided an age of 1088±9Ma. This granite contains a pervasive foliation (S2), partly obliterated in charnockitic patches, indicating that both the D2 event and the charnockitisation are younger. This confirms previous work in which the maximum age of the main fabric-forming deformation was constrained by the 1091±9Ma age of the Glenmore Granite. A sample from the garnet leucogranite in the type area of the Margate Granite Suite yielded an age of 1043±4Ma, which is statistically similar to that of the previously dated, garnet-free leucogranite of the Portobello granite, and zircon metamorphic dates of the secondary charnockitisation event associated with emplacement of the Oribi Gorge Suite. Our new data show that the Margate Terrane was subjected to at least four magmatic/thermal events, at ~1170Ma, ~1135-1140Ma, ~1082-1093Ma, and 1025-1050Ma. These events can be correlated with coeval magmatic and thermal episodes in surrounding crustal blocks within Rodinia and Gondwana. In particular the Margate Terrane appears to correlate well with the Vardeklettane Terrane of Dronning Maud Land, East Antarctica and furthermore that the Natal belt may be up to 80Ma older than the Maud belt east of the Heimefront Shear Zone, which is made up of younger crust which was accreted westwards against the Natal belt. In this scenario, the Cape Merdith Complex, West Falkland, which shows no zircon evidence of crust older than ca. 1135 Ma, forms part of the Maud belt, not the older Natal belt. © 2015 Elsevier B.V.


De Beer C.H.,Council for Geoscience
South African Journal of Geology | Year: 2012

This paper reports on the results of a systematic investigation into evidence of near-surface and surface deformation of Late Cenozoic sediments along the West Coast of South Africa. Regional studies were supplemented by the investigation of pit faces in diamond mines owned by De Beers Consolidated Mines (Pry) Ltd between Hondeklip Bay and Kleinsee and inspection of exploratory trench logs kept by Alexkor at Alexander Bay. The results provide the first substantiation for previous unverified reports of neotectonic faulting in Pliocene to Pleistocene formations along the Namaqualand coast. Associated deformation of unconsolidated marine sediments suggests that the faulting was seismogenic. The interpretations of some of the observed features remain preliminary and the age of the structures is in most cases not well constrained. Some of the faulting at Hondeklip Bay is clearly younger that 3 Ma and the youngest surface rupture observed may be of latest Pleistocene age. This style of reactivation of coast-parallel Mesozoic or older faults is similar to that recently described in Namibia, and known Quaternary reactivation of the Kango fault system in the Southern Cape. © 2012 June Geological Society of South Africa.

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