Journal articles: 'Sandton (South Africa)'

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Drew, A. "Interview with Mandla Langa Sandton, South Africa, 20 July 2001." Comparative Studies of South Asia, Africa and the Middle East 20, no. 1-2 (January 1, 2000): 148–56. http://dx.doi.org/10.1215/1089201x-20-1-2-148.

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Zavyalova, Natalya, Evgenia Evgenevna Frolova, Vitaliy Vasilievich Bezbakh, Ekaterina Petrovna Rusakova, and Mihail Nikolaevich Dudin. "BRICS Message From South Africa." Revista Amazonia Investiga 9, no. 26 (February 21, 2020): 529–44. http://dx.doi.org/10.34069/ai/2020.26.02.60.

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The paper features the data obtained from the analysis of a video strip with the help of ELAN 5.4, the free software developed by the experts from Max Planck Institute for Psycholinguistics, the Language Archive, Nijmegen, the Netherlands. The software enables to annotate video and audio strips, describing pauses, the duration of utterances, gestures, pronunciation and other linguistic and extralinguistic factors. The speaker in the video – South African President Cyril Ramaphosa – delivers his official address to the leaders of the 10th BRICS leadership summit in Sandton, Johannesburg on July 26, 2018. BRICS is a powerful link of a global financial architecture. Its main targets are to mobilize resources for sustainable development projects of BRICS and to facilitate the global growth of multilateral and regional financial, educational and industrial institutions. The material and the speaker for the analysis belong to the domain of BRICS top level politics. South Africa was the main host of the leadership summit in 2018. South African President Cyril Ramaphosa in his speech stressed the significance of the fourth industrial revolution highlighted by Professor Klaus Schawb at the World Economic Forum in Davos in 2016. The notion of the revolution appeared in the South African leader's address 7 times. Nevertheless, the authors of the paper see more messages hidden between the lines of the South African President's address. In the paper it is argued that BRICS architecture has a right to be interpreted as an attempt of keeping the world away from further plunging into environmental degradation, the development of critical thinking and innovation among BRICS citizens. The purpose of the paper is to demonstrate the method of pauses analysis to reveal a more complex mixture of speakers' visions. Long pauses are meaningful and extremely informative for discourse analysis. The data may be relevant for discourse analysis experts, political journalists, educators and copywriters.

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MacKeown, Jennifer M., and Mieke Faber. "Urbanisation and cariogenic food habits among 4–24-month-old black South African children in rural and urban areas." Public Health Nutrition 5, no. 6 (December 2002): 719–26. http://dx.doi.org/10.1079/phn2002358.

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AbstractObjective:To determine if social class, education level and group environment (rural and urban) influence particular food habits commonly associated with dental caries incidence among 4–24-month-old black South African children.Design, setting and subjects:Information was collected by trained interviewers using a food-frequency questionnaire from mothers of children in two areas in South Africa: Ndunakazi, a rural area in KwaZulu/Natal (n = 105) and two urban areas in Gauteng – Soweto (low to middle socio-economic area) (n = 100) and the northern suburbs of Johannesburg and Sandton (middle to upper socio-economic area) (n = 101). Education level and occupation of the parents, which define social class, were also recorded. A linear logistic (Proc Catmod) analysis tested social class, education level and group environment as the independent variables and the food habits as the dependent variables.Results:Group environment was significantly associated with nine of the 18 food habits investigated. More urban than rural mothers added sugar to their child's comforter. More mothers in urban Soweto than in urban Johannesburg were still breast-feeding their infants at 24 months. More rural than urban mothers were giving ‘mutis’ (common and traditional medicines). Together with group environment, education level was significantly associated with giving of ‘mutis’ and the frequency of giving them. Social class was significantly associated with the frequency of breast-feeding and when the child was breast-fed. Mothers from the upper social class breast-fed less frequently than mothers from the lower class.Conclusion:The study showed a strong influence of rural/urban environment on specific cariogenic food habits among young black South African children, enabling the development and implementation of a nutrition strategy.

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Chan, Sze Wai, and Daniel Vorobiof. "P2.03b-055 Survival in Non-Small Cell Lung Cancer (NSCLC) Patients (pts) with Driver Mutations at Sandton Oncology Centre, South Africa." Journal of Thoracic Oncology 12, no. 1 (January 2017): S969. http://dx.doi.org/10.1016/j.jtho.2016.11.1336.

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Botha, A. E., M. L. Schulman, H. J. Bertschinger, A. J. Guthrie, C. H. Annandale, and S. B. Hughes. "The use of a GnRH vaccine to suppress mare ovarian activity in a large group of mares under field conditions." Wildlife Research 35, no. 6 (2008): 548. http://dx.doi.org/10.1071/wr07136.

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The aim of this study was to evaluate the effect of active immunisation against GnRH on ovarian activity and serum progesterone concentrations in a large group of mares (10 control and 55 experimental) under field conditions as a model for wildlife species such as zebra and African elephants. Within the experimental group, mares were subdivided into three age categories: Category 1 (4 years and younger, n = 26), Category 2 (4–10 years old, n = 18), and Category 3 (≥11 years old, n = 11). Experimental mares were vaccinated intramuscularly with 2 mL (400 μg) of the GnRH vaccine Improvac (Pfizer Animal Health, Sandton, South Africa). Control mares received the same amount of saline solution. The vaccinations were repeated 35 days later. The ovaries and reproductive tracts of each mare were examined by means of rectal palpation and ultrasonography on Days 0, 35 and 70. Blood was collected weekly for determination of serum progesterone concentration until Day 175. On Day 35 after primary vaccination all of the control mares and 14.5% of the experimental mares showed evidence of ovarian activity on the basis of clinical examination and serum progesterone concentration. On Day 70, all control mares and none of the experimental mares showed evidence of cyclic activity. No age-related effect within treatment groups was found. The serum progesterone concentration indicated that all experimental mares remained in anoestrus until Day 175. Five of the control mares fell pregnant between Days 35 and 70. The five non-pregnant control mares continued to cycle until the end of the observation period. Having achieved such promising results in this trial we now plan to test the GnRH vaccine in Burchell’s zebra mares and African elephant cows.

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Masia, Thendo, Kahilu Kajimo-Shakantu, and Akintayo Opawole. "A case study on the implementation of green building construction in Gauteng province, South Africa." Management of Environmental Quality: An International Journal 31, no. 3 (February 18, 2020): 602–23. http://dx.doi.org/10.1108/meq-04-2019-0085.

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PurposeGreen building is a relatively new concept with limited applications in property development in South Africa. The objectives of this study are therefore threefold: identify key green building principles considered by property developers, establish the benefits of implementing the principles and determine the barriers to its applications.Design/methodology/approachThe study adopted a case study of two Green Star South Africa (SA)-certified buildings in Sandton, Johannesburg. These are Alexander Forbes building, and Ernst & Young Eris Towers. The two certified buildings were purposefully selected because of the insightful information they provide regarding application of green building principles. The main themes investigated in the cases are environmental awareness, green building principles applications, as well as benefits and barriers of green building. A total of six interviewees from the contractors', property developers', environmental/green building consultants' and sustainability consultants' organizations who were involved in the implementation of green building principles in the two cases provided the qualitative data for the study. The qualitative data were supplemented with data relating to the two case studies obtained from the ‘Earth Works for a Sustainable Built Environment’. The interviews were arranged over a period of two months, and each interview took between 20 and 30 minutes. Analysis of the data was done through a phenomenological interpretation of the qualitative opinions expressed by the interviewees.FindingsKey green building principles comprising energy efficiency, water efficiency, resource efficiency, occupants' health and well-being and sustainable site development were implemented in the two cases. The fact that the buildings were rated 4-star enabled inference to be drawn that the implementation of the principles was less than 60 per cent. Energy efficiency of 35 per cent indicated in Case I suggests that the level is consistent with the South African green building standard of 25 per cent to 50 per cent. However, the energy and water efficiency assessment of the building were based on projections rather than on ongoing monitoring and evaluation of the buildings' performance. Moreover, perceived saving in operational cost was identified as dominant driver to green building principles implementation. Conversely, lack of government incentives and absence of reliable benchmarking data regarding performance of green buildings were major barriers to its full implementation.Practical implicationsThe findings of this study provide important implications to the developers and government on the application of green building principles. In the first place, the evidence that initial high cost premium could be off settled by long- term saving on operational costs as a result of use of local materials, energy and water savings as well as use of recycled material, as implemented in the two case projects, would improve investment decision in green building by developers. The understanding of the drivers and barriers to implementation of green building principles also has implications for guiding government policies and programmes towards green building.Originality/valueThe significance of this study stems from the fact that limited studies, especially in the South African context, have indicated the drivers and barriers to the implementation of green building principles. The case study approach adopted gave a novelty to the study by providing hands-on information from the stakeholders who were known to have played specific roles in the application of green building. The findings indicated that initial high cost premium was not a consideration in developers' choice of green building which justifies the possibility of a costlier product when factors such as environmental sustainability benefit is considered to be ultimate. The study thus suggests further research involving larger cases on energy efficiency, water efficiency and costs of green buildings compared to the conventional type to bring the findings to a broader perspective and assist to benchmark data for green building assessment.

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FREUND, BILL. "INEQUALITY AND THE CAUSES OF POVERTY IN SOUTH AFRICA - Class, Race and Inequality in South Africa. By Jeremy Seekings and Nicoli Natrass. New Haven and London: Yale University Press, 2005. Pp. x+446. $60 (isbn978-030-010-8927). - A History of Inequality in South Africa 1652–2002. By Sampie Terreblanche. Pietermaritzburg and Sandton: University of Natal Press and KMM Review Press, 2002. Pp. xvi+527. £37.50 (isbn978-1869-140-229)." Journal of African History 50, no. 1 (March 2009): 129–32. http://dx.doi.org/10.1017/s0021853709004253.

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Weber, Bettina, Dirk C. J. Wessels, and Burkhard Büdel. "Biology and ecology of cryptoendolithic cyanobacteria of a sandstone outcrop in the Northern Province, South Africa." Algological Studies/Archiv für Hydrobiologie, Supplement Volumes 83 (December 19, 1996): 565–79. http://dx.doi.org/10.1127/algol_stud/83/1996/565.

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Andersen, T., G. A. Botha, and M. A. Elburg. "A late Mesozoic – early Cenozoic sedimentary recycling system on the Gondwana rifted margin of southeast Africa." South African Journal of Geology 123, no. 3 (September 1, 2020): 343–56. http://dx.doi.org/10.25131/sajg.123.0023.

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Abstract Detrital zircons in late Cretaceous – Palaeogene, calcareous sandstone and conglomerate deposited in continental basins on the southeastern African margin after the breakup of Gondwana have characteristic combinations of age and epsilon-Hf that indicate an origin by recycling of Palaeoproterozoic (Waterberg, Soutpansberg and Pretoria groups) and Phanerozoic (Karoo Supergroup) cover successions. The latter is dominant in the south and east (Boane, Mahosi, Chilojo Cliffs), and the Palaeoproterozoic sources in the northwest (Pafuri, Wright’s Tower, Masisi). This recycling and mixing regime was restricted to late Mesozoic and Palaeogene time in northeastern South Africa and adjoining parts of Mozambique and Zimbabwe. Detrital zircon distribution patterns in these deposits reflect the denudation history of the southern African continental surface after breakup of the Gondwana supercontinent.

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Cole, Doug. "Heritage stone in Cape Town, South Africa." Geological Society, London, Special Publications 486, no. 1 (September 20, 2018): 305–23. http://dx.doi.org/10.1144/sp486.3.

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AbstractCape Town was founded in 1652 and many of its historical buildings are constructed of local natural stone. Malmesbury Group slate was exploited from 1666 and used to build Cape Town Castle, which is the oldest building in Cape Town. Two other local stones, Cape granite and Table Mountain sandstone were utilized for buildings from 1850. A medium-grained granite named Paarl Grey was exploited from an area adjacent to the town of Paarl, 50 km east of Cape Town, from 1890. This granite is the most extensively-used natural stone in Cape Town.The resource fields of natural stone near Cape Town, namely Malmesbury Group slate, Cape granite and Table Mountain sandstone, lie within the Table Mountain National Park and Robben Island World Heritage Site and can no longer be exploited, but similar resource fields occur outside Cape Town. Paarl Grey granite is still extracted at one quarry and, despite part of the resource field lying within the Paarl Mountain Nature Reserve, there are still sufficient quantities of stone available.From an international perspective, the heritage stones of Cape Town, South Africa, are best considered as having national significance.

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Coppins, B. J. "Two New Species of Micarea From South Africa." Lichenologist 31, no. 6 (November 1999): 559–65. http://dx.doi.org/10.1006/lich.1999.0234.

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AbstractTwo new species of Micarea are described from South Africa: M. almbornii Coppins, on loose sandstone from Stellenbosch (Western Cape) and M. endoviolascens Coppins, on damp soil from Transvaal. A note is given on Lecidea geïna Stizenb.

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Evans, Mary, Bridget Fleming, and Gillian Drennan. "Can the augmented reality sandbox help learners overcome difficulties with 3-D visualisation?" Terrae Didatica 14, no. 4 (November 30, 2018): 389–94. http://dx.doi.org/10.20396/td.v14i4.8654110.

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Research has shown that students have difficulties in understanding topographic maps and landforms associated with contour patterns and therefore have problems in reading and interpreting topographic maps and relating these 2-dimensional representa-tions to a real 3-dimensional environment. However, maps are a fundamental tool for understanding geographical concepts and solving geographical problems. Current research indicates that this is not uniquely a South African problem and various at-tempts have been made to address this problem such as the use of videos, models and fieldtrips – each with their own limita-tions and difficulties. Nevertheless, the ability to visualize in 3-dimensions from a 2-dimensional representation is an essential skill in understanding and interpreting topographical maps. To address the problem of 3-D visualisation, an augmented reality sandbox (AR-Sandbox) was introduced to a Geography classroom, to Grade 11 students at a Secondary school in Johannes-burg, South Africa. The aim of this study is to determine the effectiveness of using the AR-Sandbox to enhance the learning of – and improve the learner's performance – in mapwork, and thereby address the problems experienced with 3-D visualisation. The results of the pre-test and post-intervention test are presented and show that the AR-Sandbox is an effective tool for en-hancing an understanding of landscapes rather an improving performance in the construction of cross-sectional profiles.

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DEMLIE, M., and R. TITUS. "HYDROGEOLOGICAL AND HYDROGEOCHEMICAL CHARACTERISTICS OF THE NATAL GROUP SANDSTONE, SOUTH AFRICA." South African Journal of Geology 118, no. 1 (March 1, 2015): 33–44. http://dx.doi.org/10.2113/gssajg.118.1.33.

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Opuwari, M., M. Amponsah-Dacosta, S. Mohammed, and N. Egesi. "Delineation of sandstone reservoirs of Pletmos Basin offshore South Africa into Flow Units using Core Data." South African Journal of Geology 123, no. 4 (October 26, 2020): 479–92. http://dx.doi.org/10.25131/sajg.123.0032.

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Abstract The present study is focused on the comparison of petrophysical rock typing and zonation methods of the Valanginian age sandstone in the Pletmos Basin offshore South Africa, to produce a zonation scheme for the low-permeability shaly sandstone reservoirs from core porosity and permeability data. The Valanginian age sediments of the Lower Cretaceous consist predominantly of a shallow marine sequence with interbeds of siltstone, claystone, generally fine-grained sandstone, and glauconitic, with varying amounts of an argillaceous matrix. A core description report was used in conjunction with a gamma-ray log to group rock types into different facies based on texture and grain size. Three different facies were identified as facies 1, a moderately sorted fine to medium-grained glauconitic sandstone; facies 2, a fine to very fine-grained glauconitic sandstone, moderately sorted; facies 3, a very fine sandstone to siltstone, laminated, argillaceous and bioturbated. Three independent reservoir zonation methods (Winland r35 pore throat, Hydraulic Flow Unit, and Stratigraphic Modified Lorenz Plot) were applied to three wells (SW1, SW2, and SW3) for which wireline logs, core porosity, and permeability data are available. Results were analyzed and compared with facies used as a context for the identification of rock types and zones. The results revealed eleven zones, grouped as moderate, very-low, and tight zones. The moderate flow zone is the best reservoir quality rock composed of macroporous rock type, ranked, as good rock type associated with facies 1. Three very-low flow zones were identified, which are of a microporous rock type, ranked as poor quality rock, associated with facies 2. Eight tight zones were revealed, which are of nanoporous rock type ranked as an impervious rock. The tight flow zone is the most reduced rock quality associated with facies 3. This study has developed a zonation scheme that will be used to locate other flow zones as well as to investigate whether the units/zones identified extend to other parts of the field.

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Byerly, Benjamin L., Donald R. Lowe, Nadja Drabon, Matthew A. Coble, Dale H. Burns, and Gary R. Byerly. "Hadean zircon from a 3.3 Ga sandstone, Barberton greenstone belt, South Africa." Geology 46, no. 11 (September 27, 2018): 967–70. http://dx.doi.org/10.1130/g45276.1.

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ROGERS, D. CHRISTOPHER, MURPHY TLADI, RYAN J. WASSERMAN, and ELIZABETH MEYER-MILNE. "Review of the southern African Leptestheriidae (Branchiopoda: Spinicaudata) I: redescription of Leptestheria brevirostris Barnard, 1924 with comments on diagnostic characters." Zootaxa 4974, no. 2 (May 20, 2021): 258–66. http://dx.doi.org/10.11646/zootaxa.4974.2.2.

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We present the first records of Leptestheria brevirostris since its discovery in Namibia by Barnard in 1924. Our records come from Botswana and South Africa, and present significant range extensions. We redescribe L. brevirostris according to modern standards and present the first description of the male. We also discovered that L. brevirostris is likely a rock pool specialist, specific to sandstone and gneiss outcrops; this is the first record of a rock pool specialist clam shrimp from Africa and the second rock pool specialist described for Leptestheriidae. Finally, we depict and discuss the validity and usefulness of diagnostic characters for Leptestheria species in southern Africa, especially the usefulness of carapace interval ornamentation.

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Victor, J. E., D. B. Hoare, and R. A. Lubke. "Checklist of plant species of the coastal fynbos and rocky headlands, south of George, South Africa." Bothalia 30, no. 1 (February 3, 2000): 97–101. http://dx.doi.org/10.4102/abc.v30i1.544.

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A checklist of vascular plants and cryptograms was compiled for the fynbos and rocky headland communities of the coastal region south of George The area studied is a 12 km stretch of steep sandstone cliffs forming alternating bays and headlands situated between Glentana and Wilderness. The plant communities of the natural vegetation inhabiting the coastline are a mixture of coastal thicket, riparian thicket, fynbos and rocky headland types. The extent of natural vegetation has been reduced by the spread of agricultural land and urban development and is under further threat from the spread of naturalised alien invader species, particularly Acacia cyclops. The checklist records the occurrence of 271 taxa including 16 alien species (6% of taxa). Of the flowering plant species recorded, 6% were regional or local endemics.

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Wessels, D. C. J., and L. A. Wessels. "Erosion of Biogenically Weathered Clarens Sandstone by Lichenophagous Bagworm Larvae (Lepidoptera; Pyschidae)." Lichenologist 23, no. 3 (July 1991): 283–91. http://dx.doi.org/10.1017/s0024282991000439.

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AbstractLichenophagous larvae of a bagworm moth species, associated with endolithic lichens occur in the Golden Gate Highlands National Park, South Africa. Endolithic lichens weather Clarens sandstone in the park by dissolving the cementing material of the sandstone. Bagworm larvae use such loosened quartz crystals to construct the bags in which they live. By erosion of the weathered sandstone, the bagworm larvae contribute to pedogenesis in the park at an estimated rate of 4.4 kilograms per hectare per year. In addition, bagworm larvae utilize endolithic lichens as a food source and contribute to dispersal of the lichens. The larvae further contribute an estimated 200 g of organic matter per hectare per year to the park and partake in the cycling of elements in the micro-ecosystem.

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Andersen, T., M. A. Elburg, and J. Lehmann. "Enigmatic provenance signature of sandstone from the Okwa Group, Botswana." South African Journal of Geology 123, no. 3 (September 1, 2020): 331–42. http://dx.doi.org/10.25131/sajg.123.0022.

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Abstract Detrital zircon grains from three samples of sandstone from the Tswaane Formation of the Okwa Group of Botswana have been dated by U-Pb and analysed for Hf isotopes by multicollector LA-ICPMS. The detrital zircon age distribution pattern of the detrital zircons is dominated by a mid-Palaeoproterozoic age fraction (2 000 to 2 150 Ma) with minor late Archaean – early Palaeoproterozoic fractions. The 2 000 to 2 150 Ma zircon grains show a range of epsilon Hf from -12 to 0. The observed age and Hf isotope distributions overlap closely with those of sandstones of the Palaeoproterozoic Waterberg Group and Keis Supergroup of South Africa, but are very different from Neoproterozoic deposits in the region, and from the Takatswaane siltstone of the Okwa Group, all of which are dominated by detrital zircon grains younger than 1 950 Ma. The detrital zircon data indicate that the sources of Tswaane Formation sandstones were either Palaeoproterozoic rocks in the basement of the Kaapvaal Craton, or recycled Palaeoproterozoic sedimentary rocks similar to the Waterberg, Elim or Olifantshoek groups of South Africa. This implies a significant shift in provenance regime between the deposition of the Takatswaane and Tswaane formations. However, the detrital zircon data are also compatible with a completely different scenario in which the Tswaane Formation consists of Palaeoproterozoic sedimentary rock in tectonic rather than depositional contact with the other units of the Okwa Group.

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Akinlua, A., A. Ngola, O. A. Fadipe, and S. A. Adekola. "Petrography and geochemistry of sandstone samples of Vischkuil formation, Karoo Supergroup, South Africa." Journal of Petroleum Exploration and Production Technology 6, no. 2 (November 16, 2015): 159–67. http://dx.doi.org/10.1007/s13202-015-0199-1.

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Hlongwane, Zabentungwa Thakasile, Tarombera Mwabvu, Thinandavha Caswell Munyai, and Zivanai Tsvuura. "Epigaeic ant diversity and distribution in the Sandstone Sourveld in KwaZulu‐Natal, South Africa." African Journal of Ecology 57, no. 3 (April 16, 2019): 382–93. http://dx.doi.org/10.1111/aje.12615.

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Opuwari, Mimonitu, and Nehemiah Dominick. "Sandstone reservoir zonation of the north-western Bredasdorp Basin South Africa using core data." Journal of Applied Geophysics 193 (October 2021): 104425. http://dx.doi.org/10.1016/j.jappgeo.2021.104425.

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Snijman, D. A. "Two new species of Spiloxene (Hypoxidaceae) from the northwestern Cape, South Africa." Bothalia 36, no. 2 (August 21, 2006): 133–38. http://dx.doi.org/10.4102/abc.v36i2.351.

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Newly described are two new species of Spiloxene Salisb.: S. nana Snijman from the Bokkeveld Escarpment, Northern Cape Province, is a shade-loving plant with narrow, pale green leaves and small, white or rarely cream-coloured flowers; S. pusilla Snijman from the Matsikamma, Gifberg and Pakhuis Mountains. Western Cape Province, resembles S. nana in habit but the yellow- or white-tepalled flowers which are tetramerous or hexamerous have darkly coloured stamens and style and an ovary with a short, solid, narrow prolongation at the apex. Inhabiting rock overhangs formed by quartzitic sandstone sheets, both species are close allies of S. scullyi (Baker) Garside from Namaqualand.

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Malaza, Ntokozo, Kuiwu Liu, and Baojin Zhao. "Facies Analysis and Depositional Environments of the Late Palaeozoic Coal-Bearing Madzaringwe Formation in the Tshipise-Pafuri Basin, South Africa." ISRN Geology 2013 (December 11, 2013): 1–11. http://dx.doi.org/10.1155/2013/120380.

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The late Palaeozoic coal-bearing Madzaringwe Formation of the Karoo Supergroup in the Tshipise-Pafuri Basin in the Limpopo Province, South Africa, records part of the infill of a passive continental margin terrain. Lithofacies analysis was performed with a view to deduce the nature of depositional environments of the Formation. Sedimentological and sequence stratigraphic evidence indicates that this unit represents a complex siliciclastic facies that reflects a fluvial paleodepositional environment. Eleven facies, which were grouped into five facies associations, were recognised. The base of the Madzaringwe Formation (Lower Member) represents a sequence deposited by braided channels. The coal deposits represent flood plain and swamp deposits, which is characterised by shale, thick coal seams, siltstone, and sandstone. The Middle Member is characterised by both clast and matrix supported conglomerates, major tubular and lenticular sandstones, and finely calcareous, micaceous siltstone. The deposition represents a sequence being formed from fluvial and particularly braided channels. The crudely stratified, coarse to pebbly sandstone indicates channel lag deposits within a heavy loaded fluvial system. The fine-grained sandstone represents deposition by shift channel and side bar deposits during lower flow conditions. The Upper Member is characterised by facies associations similar to the Lower Member, representing a new depositional cyclothem.

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Jaarsveld, Ernst J. van, Nick Helme, and Derek Tribble. "Crassula fragarioides, a new sandstone outcrop species from the Bokkeveld Escarpment, Northern Cape, South Africa." Bradleya 29, no. 29 (December 31, 2011): 51–56. http://dx.doi.org/10.25223/brad.n29.2011.a5.

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Nocita, Bruce W. "Sandstone petrology of the Archean Fig Tree Group, Barberton greenstone belt, South Africa: Tectonic implications." Geology 17, no. 10 (1989): 953. http://dx.doi.org/10.1130/0091-7613(1989)017<0953:spotaf>2.3.co;2.

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Steiner, K. E. "Three new species of Diascia (Scrophulariaceae) from the Western Cape, South Africa." Bothalia 39, no. 1 (August 11, 2009): 11–17. http://dx.doi.org/10.4102/abc.v39i1.226.

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Three new annual species of Diascia Link Otto are described from the Western Cape Province of South Africa. D. collina is characterized by greyish magenta flowers with two divergent yellow sacs containing oil-secreting trichomes. It is restricted to granite outcrops in the vicinity of Saldanha Bay, from the West Coast National Park and Langebaan north to Vredenburg. D. pusilla is closely related to D. collina. but differs from that species in having smaller flowers with shorter, ± parallel sacs, and posticous filaments that lack a protuberance where they bend sharply backwards towards the upper lip. It occurs in grey to whitish sands usually near seasonally moist or wet areas. It has not been found more than 35 km from the coast and ranges from Modderrivier, south o f Darling, north to Lambert’s Bay. D. appendiculata is related to D. diffusa (Thunb.) Benth. and is characterized by having small, mainly reddish lilac to greyish magenta flowers, two shallow depressions in the corolla tube at the base of the upper lip, and posticous filaments with sterile appendages. It is known from only six localities in the general vicinity of Citrusdal and occurs in fynbos vegetation on lower mountain slopes or flats, in loose alluvial sands derived from Table Mountain Sandstone.

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Wickens, H. de V., and D. I. Cole. "Lithostratigraphy of the Skoorsteenberg Formation (Ecca Group, Karoo Supergroup), South Africa." South African Journal of Geology 120, no. 3 (September 1, 2017): 433–46. http://dx.doi.org/10.25131/gssajg.120.3.433.

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Abstract The Middle Permian Skoorsteenberg Formation is part of the Ecca Group (Karoo Supergroup) of South Africa. It is also known as the ‘Tanqua fan complex’ due to its origin as a deep-water sedimentation unit associated with a prograding deltaic system. The Skoorsteenberg Formation crops out over approximately 650 km2 along the western margin of the Main Karoo Basin. It thins out in a northerly and easterly direction and therefore has a limited extent with cut-off boundaries to the south and north. It is underlain by the Tierberg Formation and overlain by the Kookfontein Formation, the latter being limited to the regional distribution of the Skoorsteenberg Formation. The Skoorsteenberg Formation has a composite thickness of 400 m and comprises five individual sandstone packages, separated by shale units of similar thickness. The sandstones are very fine- to fine-grained, light greyish to bluish grey when fresh, poorly sorted and lack primary porosity and permeability. The Tanqua fan complex is regarded as one of the world’s best examples of an ancient basin floor to slope fan complex associated with a fluvially dominated deltaic system. It has served as analogue for many deep-water systems around the world and continues to be a most sought after “open-air laboratory” for studying the nature of fine-grained, deep-water sedimentation. The fan systems are essentially tectonically undeformed, outstandingly well exposed and contain an inexhaustible amount of information on the deep-water architecture of lower slope to basin floor turbidite deposits.

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Drabon, Nadja, Benjamin L. Byerly, Gary R. Byerly, Joseph L. Wooden, C. Brenhin Keller, and Donald R. Lowe. "Heterogeneous Hadean crust with ambient mantle affinity recorded in detrital zircons of the Green Sandstone Bed, South Africa." Proceedings of the National Academy of Sciences 118, no. 8 (February 18, 2021): e2004370118. http://dx.doi.org/10.1073/pnas.2004370118.

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The nature of Earth’s earliest crust and the processes by which it formed remain major issues in Precambrian geology. Due to the absence of a rock record older than ∼4.02 Ga, the only direct record of the Hadean is from rare detrital zircon and that largely from a single area: the Jack Hills and Mount Narryer region of Western Australia. Here, we report on the geochemistry of Hadean detrital zircons as old as 4.15 Ga from the newly discovered Green Sandstone Bed in the Barberton greenstone belt, South Africa. We demonstrate that the U-Nb-Sc-Yb systematics of the majority of these Hadean zircons show a mantle affinity as seen in zircon from modern plume-type mantle environments and do not resemble zircon from modern continental or oceanic arcs. The zircon trace element compositions furthermore suggest magma compositions ranging from higher temperature, primitive to lower temperature, and more evolved tonalite-trondhjemite-granodiorite (TTG)-like magmas that experienced some reworking of hydrated crust. We propose that the Hadean parental magmas of the Green Sandstone Bed zircons formed from remelting of mafic, mantle-derived crust that experienced some hydrous input during melting but not from the processes seen in modern arc magmatism.

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Wessels, D. C. J., and B. Büdel. "A Rock Pool Lichen Community in Northern Transvaal, South Africa: Composition and Distribution Patterns." Lichenologist 21, no. 3 (July 1989): 259–77. http://dx.doi.org/10.1017/s0024282989000484.

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AbstractThe distribution patterns of lichens belonging to the family Peltulaceae and procaryotic algae (cyanobacteria) were studied in a rock pool on a sandstone koppie (‘Inselberg’). situated in the mopane savanna of the northern Transvaal. The co-dominant lichen species along the wall of the pool were: Peltula clavata (Krempelh.) Wetmore, P. euploca (Ach.) Poelt ex Pisut, P. obscurans (Nyl.) Gyelnik, and P. placodizans (Zahlbr.) Wetmore. The cyanobacteria Gloeocapsa sanguinea (Ag.) Kütz. emend. Jaag, Plectonema tomasinianum Gom. ex Gom., Rivularia sp., Scytonema sp. and Tolypothrix sp. grew epilithically between the lichen thalli. Unicellular species of the genus Chroococcidiopsis Geitler or Myxosarcina Printz occurred cryptoendolithically. The distribution patterns of several lichen species are presented and statistical tests reveal distinct correlations of the habitats of some species with light levels and water supply; e.g. the olive-green P. placodizans preferred the fully exposed situation near and along the rim of the rock pool; the black species P. clavata was restricted to areas next to the water level.

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Baiyegunhi, Christopher, and Kuiwu Liu. "Sedimentary facies, stratigraphy, and depositional environments of the Ecca Group, Karoo Supergroup in the Eastern Cape Province of South Africa." Open Geosciences 13, no. 1 (January 1, 2021): 748–81. http://dx.doi.org/10.1515/geo-2020-0256.

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Abstract The stratigraphy of the Ecca Group has been subdivided into the Prince Albert, Whitehill, Collingham, Ripon, and Fort Brown Formations in the Eastern Cape Province, South Africa. In this article, we present detailed stratigraphic and facies analyses of borehole data and road-cut exposures of the Ecca Group along regional roads R67 (Ecca Pass), R344 (Grahamstown-Adelaide), R350 (Kirkwood-Somerset East), and national roads N2 (Grahamstown-Peddie) and N10 (Paterson-Cookhouse). Facies analysis of the Ecca Group in the study area was performed to deduce their depositional environments. Based on the lithological and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham, and Fort Brown Formations is now subdivided into two informal members each, while the Ripon Formation is subdivided into three members. A total of twelve lithofacies were identified in the Ecca Group and were further grouped into seven distinct facies associations (FAs), namely: Laminated to thin-bedded black-greyish shale and mudstones (FA 1); Laminated black-greyish shale and interbedded chert (FA 2); Mudstone rhythmite and thin beds of tuff alternation (FA 3); Thin to thick-bedded sandstone and mudstone intercalation (FA 4); Medium to thick-bedded dark-grey shale (FA 5); Alternated thin to medium-bedded sandstone and mudstone (FA 6); and Varved mudstone rhythmite and sandstone intercalation (FA 7). The FAs revealed gradually change of sea-level from deep marine (FA 1, FA 2, FA 3 and FA 4, FA 5, and FA 6) to prodelta environment (FA 7). This implies that the main Karoo Basin was gradually filling up with Ecca sediments, resulting in the gradual shallowing up of the water depth of the depositional basin.

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FADIPE, O. A., P. F. CAREY, A. AKINLUA, and S. A. ADEKOLA. "PROVENANCE, DIAGENESIS AND RESERVOIR QUALITY OF THE LOWER CRETACEOUS SANDSTONE OF THE ORANGE BASIN, SOUTH AFRICA." South African Journal of Geology 114, no. 3-4 (December 1, 2011): 433–48. http://dx.doi.org/10.2113/gssajg.114.3-4.433.

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Raitt, L. M., and R. O. Moffett. "The cation status of some indigenous plants from a Cango valley limestone-sandstone transition, South Africa." Plant and Soil 101, no. 1 (March 1987): 95–98. http://dx.doi.org/10.1007/bf02371035.

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Opuwari, Mimonitu, Moses Magoba, Nehemiah Dominick, and Nicolas Waldmann. "Delineation of Sandstone Reservoir Flow Zones in the Central Bredasdorp Basin, South Africa, Using Core Samples." Natural Resources Research 30, no. 5 (May 31, 2021): 3385–406. http://dx.doi.org/10.1007/s11053-021-09885-7.

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KOLODNER, K., D. AVIGAD, M. McWILLIAMS, J. L. WOODEN, T. WEISSBROD, and S. FEINSTEIN. "Provenance of north Gondwana Cambrian–Ordovician sandstone: U–Pb SHRIMP dating of detrital zircons from Israel and Jordan." Geological Magazine 143, no. 3 (March 31, 2006): 367–91. http://dx.doi.org/10.1017/s0016756805001640.

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A vast sequence of quartz-rich sandstone was deposited over North Africa and Arabia during Early Palaeozoic times, in the aftermath of Neoproterozoic Pan-African orogeny and the amalgamation of Gondwana. This rock sequence forms a relatively thin sheet (1–3 km thick) that was transported over a very gentle slope and deposited over a huge area. The sense of transport indicates unroofing of Gondwana terranes but the exact provenance of the siliciclastic deposit remains unclear. Detrital zircons from Cambrian arkoses that immediately overlie the Neoproterozoic Arabian–Nubian Shield in Israel and Jordan yielded Neoproterozoic U–Pb ages (900–530 Ma), suggesting derivation from a proximal source such as the Arabian–Nubian Shield. A minor fraction of earliest Neoproterozoic and older age zircons was also detected. Upward in the section, the proportion of old zircons increases and reaches a maximum (40%) in the Ordovician strata of Jordan. The major earliest Neoproterozoic and older age groups detected are 0.95–1.1, 1.8–1.9 and 2.65–2.7 Ga, among which the 0.95–1.1 Ga group is ubiquitous and makes up as much as 27% in the Ordovician of Jordan, indicating it is a prominent component of the detrital zircon age spectra of northeast Gondwana. The pattern of zircon ages obtained in the present work reflects progressive blanketing of the northern Arabian–Nubian Shield by Cambrian–Ordovician sediments and an increasing contribution from a more distal source, possibly south of the Arabian–Nubian Shield. The significant changes in the zircon age signal reflect many hundreds of kilometres of southward migration of the provenance.

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Sieben, E. J. J., C. Boucher, and L. Mucina. "Vegetation of high-altitude fens and restio marshlands of the Hottentots Holland Mountains, Western Cape, South Africa." Bothalia 34, no. 2 (September 3, 2004): 141–53. http://dx.doi.org/10.4102/abc.v34i2.428.

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Seepages occurring at high altitudes in the Hottentots Holland Mountains (HHM) (Western Cape Province. South Africa) were subject to a phytosociological survey. Relevé sampling method and classification procedures of the floristic-sociological (Braun-Blanquet) approach as well as numerical data analyses (numerical classification and ordination) were used to reveal syn- taxonomic patterns and characterize the position of the syntaxa along major environmental gradients. Nine plant communities were recognized, three of which were classified as associations, following formal syntaxonomic and nomenclatural rules of the floristic-sociological approach Most of the studied mire communities were dominated by low-growing clonal restios (Restionaceae). whereas some consisted of other types of graminoids. The most important species determining the structure (and function) of the mire communities on sandstones of the HHM include restios Anthochortus crinalis, Chondropetalum deustum.C. mucronatum, Elegia intermedia. E. thyrsifera. Restio subtilis. R. purpurascens. cyperoids Epischoenus villosus. Ficinia argy-ropa, grasses Ehrharta setacea subsp. setacea. Pentameris hirtiglumis as well as shrubs Berzelia squarrosa. Cliffortia tricuspi- data. Erica intenallaris and Grubbia rosmarinifolia. Protea lacticolor and Restio perplexus dominate a rare shale band seepage community. There are two major groups of communities—the fens (dominated by carpets of Anthochortus crinalis and other low-growing species) and the restio marshlands (mosaics of low tussocks of Restio subtilis and tall Chondropetalum mucronatum). The degree of soil (and water) minerotrophy was found to be the most important differentiating feature between the mire (fen and restio marshland) communities studied. The soils in the centre of mires were found to have high contents of peat and showed very little influence from the underlying sandstone. The soils along the mire margins had a greater admixture of mineral soil derived from the sandstone or shale bedrock.

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Hannibal, Joseph T., S. Kramar, and B. J. Cooper. "Worldwide examples of global heritage stones: an introduction." Geological Society, London, Special Publications 486, no. 1 (2020): 1–6. http://dx.doi.org/10.1144/sp486-2020-84.

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AbstractHeritage stones are stones that have special significance in human culture. The papers in this volume discuss a wide variety of such stones, including stones from Europe, Asia, North and South America, Africa and Australia. Igneous (basalt, porphyry and a variety of granites), sedimentary (sandstone, limestone) and metamorphic (marble, quartzite, gneiss, slate, soapstone) stones are featured. These stones have been used over long periods of time for a wide range of uses, including monuments, buildings of architectural note, columns, roofing, tiling and lithography. A number of papers in this book provide information that is essential for eventual approval of stones as a Global Heritage Stone Resource or a group of stones as a Global Heritage Stone Province.

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Dugas, Daniel P., and Gregory J. Retallack. "Middle Miocene fossil grasses from Fort Ternan, Kenya." Journal of Paleontology 67, no. 1 (January 1993): 113–28. http://dx.doi.org/10.1017/s0022336000021223.

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At the well-known fossil mammal locality of Fort Ternan in southwestern Kenya, radiometrically dated at about 14 million years old (middle Miocene), fossil grasses have been preserved by nephelinitic sandstone in place of growth above a brown paleosol (type Onuria clay). Large portions of grass plants as well as fragments of leaves have revealed details of silica bodies, stomates, and other taxonomically important features under the scanning electron microscope. The computer database for grass identification compiled by Leslie Watson and colleagues was used to determine the most similar living grass genera to the five distinct kinds of fossil found. Two of the fossil species are assigned to Cleistochloa kabuyis sp. nov. and C. shipmanae sp. nov. This genus includes one species from low fertility dry woodland soils of New South Wales and Queensland and a second species from “raw clay soils” in western New Guinea. A third fossil species, represented by a large portion of a branching culm, is assigned to Stereochlaena miocenica sp. nov. This genus includes five species of low-fertility woodland soils in southeastern Africa. Both Cleistochloa and Stereochlaena are in the supertribe Panicanae of the subfamily Panicoideae. A fourth species is assigned to Distichlis africana sp. nov. and provides a biogeographic link between the single species of this genus now living in coastal grasslands in southeastern Australia and the 12 species of dunes and deserts found throughout the Americas from Patagonia and the West Indies to the United States and Canada. A fifth species is, like D. africana, in the subfamily Chloridoideae, but its stomata were not seen and it could belong to Cyclostachya, Pogoneura, or Polevansia. This earliest known wooded grassland flora in Africa is taxonomically unlike the modern grass flora of fertile volcanic African landscapes, and may have been recruited from an archaic grass flora of Gondwanan desert and lateritic soils.

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Drabon, Nadja, Christoph E. Heubeck, and Donald R. Lowe. "Evolution of an Archean fan delta and its implications for the initiation of uplift and deformation in the Barberton greenstone belt, South Africa." Journal of Sedimentary Research 89, no. 9 (September 11, 2019): 849–74. http://dx.doi.org/10.2110/jsr.2019.46.

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ABSTRACT The 3.28 to 3.23 Ga Mapepe Formation in the Barberton greenstone belt, South Africa, marks the initiation of widespread tectonic uplift and deformation after nearly 300 million years of predominantly basaltic and komatiitic magmatism under largely anorogenic conditions. This rapid transition is recorded in the eastern Barite Valley area by the buildup of a fan delta. Well-exposed sections there reach about 450 m thick and can be divided (from base to top) into five informal members: Member 1 is dominated by mudstone with subordinate banded ferruginous chert and turbiditic sandstone representing a deep-water basinal environment. Member 2 is composed of siltstone and fine-grained sandstone reworked by currents to form laminated, cross-laminated, and low-angle cross-stratified sediments in an off-shore or possibly subtidal fan-delta-front setting. Member 3 overlies member 2 unconformably; it is composed of predominantly coarse-grained, cross-bedded sandstone interbedded with laminated mudstone deposited on shallow-subtidal to intertidal flats along the fringe of a small fan delta in which putative microbial mats covered low-energy upper tidal flats. Fan-delta sedimentation was subsequently overwhelmed by the influx of dacitic pyroclastic sediments of member 4. Orthochemical sedimentary rocks including barite, jaspilite, and chert deposited on top of this shallow-water bank. Mappable facies changes towards the northeast and southwest document the transition from bank top into major mass-transport deposits of fan-delta slope facies and then into basinal deposits. Subsequent relative sea-level rise resulted in the return to below-wave-base deposition of turbiditic sandstone, mudstone, and banded ferruginous chert of member 5. The lenticular geometry of units in cross section, mineralogical immaturity, and high variability in provenance of the coarse-grained units imply short-distance transport of sediment derived from strata of the underlying Onverwacht Group and from local penecontemporaneous dacitic volcanism. Throughout the greenstone belt, Mapepe rocks in several structural belts display fan deltas developed adjacent to small, local uplifts. While the cause of these uplifts has generally been associated with the initiation of geodynamically driven tectonic activity in the BGB, it is possible that a cluster of large meteorite impacts may have directly or indirectly triggered the crustal deformation.

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Bamford, M. K., B. Cairncross, and H. Lombard. "Silicified fossil woods from the Late Permian Middleton Formation, Beaufort Group, Eastern Cape Province, South Africa and their palaeoenvironmental significance." South African Journal of Geology 123, no. 4 (October 26, 2020): 465–78. http://dx.doi.org/10.25131/sajg.123.0036.

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Abstract Fossil wood is described from the Late Permian Middleton Formation, Adelaide Subgroup, Beaufort Group of the Karoo Supergroup in the Easter Cape Province, South Africa. The wood consists of in situ tree trunks up to 9 m long, partially enclosed in fine-grained sandstone surrounded by argillaceous mudstone and siltstone. The strata are poorly exposed due to the eroded and denuded land surface. All are lying horizontally and none are in upright growth positions. Comparisons of the study site lithologies with known surrounding Middleton Formation lithostratigraphy supports the interpretation that the palaeoenvironment responsible for the transport and deposition of the fossil wood was fluvial, with sandstone representing in-channel deposits and the mudstone-siltstone flood plain sequences where the trees were originally located before being uprooted and transported within the channels. Thin sections of twenty-nine wood samples revealed the presence of four existing taxa, Agathoxylon africanum, Agathoxylon karooensis, Australoxylon natalense and Australoxylon teixeirae. Growth rings of all the samples show a wide range of ring width from 1 mm to 11 mm, indicating growth under suitable climatic regimes with adequate water supply interspersed by very wet and warm periods. Crushed earlywood, s-shaped cell walls and torn cell walls suggest felling of trees during storm and/or flood events followed by sedimentary transport in palaeochannels prior deposition within the channel sands.

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Bergh, Eugene W., and John S. Compton. "A one-year post-fire record of macronutrient cycling in a mountain sandstone fynbos ecosystem, South Africa." South African Journal of Botany 97 (March 2015): 48–58. http://dx.doi.org/10.1016/j.sajb.2014.11.010.

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Wessels, D. C. J., and B. Büdel. "Epilithic and Cryptoendolithic Cyanobacteria of Clarens Sandstone Cliffs in the Golden Gate Highlands National Park, South Africa." Botanica Acta 108, no. 3 (June 1995): 220–26. http://dx.doi.org/10.1111/j.1438-8677.1995.tb00853.x.

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43

Humbert, F., A. Hofmann, M. de Kock, A. Agangi, Y.-M. Chou, and P. W. Mambane. "A geochemical study of the Crown Formation and Bird Member lavas of the Mesoarchaean Witwatersrand Supergroup, South Africa." South African Journal of Geology 124, no. 3 (September 1, 2021): 663–84. http://dx.doi.org/10.25131/sajg.124.0022.

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Abstract The ca. 2.97 to 2.80 Ga Witwatersrand Supergroup, South Africa, represents the oldest intracontinental sedimentary basin of the Kaapvaal craton. Two volcanic units occur in this supergroup: the widespread Crown Formation lavas in the marine shale-dominated West Rand Group and the more geographically restricted Bird Member lavas, intercalated with fluvial to fluvio-deltaic sandstone and conglomerate of the Central Rand Group. These units remain poorly studied as they are rarely exposed and generally deeply weathered when cropping out. We report whole-rock major and trace elements, Hf and Nd-isotope whole-rock analyses of the lavas from core samples drilled in the south of the Witwatersrand basin and underground samples from the Evander Goldfield in the northeast. In the studied areas, both the Crown Formation and Bird Member are composed of two units of lava separated by sandstone. Whereas all the Crown Formation samples show a similar geochemical composition, the upper and lower volcanic units of the Bird Member present clear differences. However, the primitive mantle-normalized incompatible trace element concentrations of all Crown Formation and Bird Member samples show variously enriched patterns and marked negative Nb and Ta anomalies relative to Th and La. Despite the convergent geodynamic setting of the Witwatersrand Supergroup suggested by the literature, the Crown Formation and Bird Member are probably not related to subduction-related magmatism but more to decompression melting. Overall, the combined trace element and Sm-Nd isotopic data indicate melts from slightly to moderately depleted sources that were variably contaminated with crustal material. Greater contamination, followed by differentiation in different magma chambers, can explain the difference between the two signatures of the Bird Member. Finally, despite previous proposals for stratigraphically correlating the Witwatersrand Supergroup to the Mozaan Group of the Pongola Supergroup, their volcanic units are overall geochemically distinct.

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Samakinde, C., M. Opuwari, and J. M. van Bever Donker. "The effects of clay diagenesis on petrophysical properties of the lower Cretaceous sandstone reservoirs, Orange Basin, South Africa." South African Journal of Geology 119, no. 1 (March 2016): 187–202. http://dx.doi.org/10.2113/gssajg.119.1.187.

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Simpson, E. L., K. A. Eriksson, P. A. Eriksson, and A. J. Bumby. "Eolian Dune Degradation and Generation of Massive Sandstone Bodies in the Paleoproterozoic Makgabeng Formation, Waterberg Group, South Africa." Journal of Sedimentary Research 72, no. 1 (January 1, 2002): 40–45. http://dx.doi.org/10.1306/050701720040.

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Opuwari, Mimonitu, Kaushalendra, B. Trivedi, and A. Momoh. "Sandstone reservoir zonation using conventional core data: A case study of lower cretaceous sandstones, Orange Basin, South Africa." Journal of African Earth Sciences 153 (May 2019): 54–66. http://dx.doi.org/10.1016/j.jafrearsci.2019.02.017.

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Campbell, Stuart A., Nils Lenhardt, Matthys A. Dippenaar, and Annette E. Götz. "Geothermal Energy from the Main Karoo Basin (South Africa): An Outcrop Analogue Study of Permian Sandstone Reservoir Formations." Energy Procedia 97 (November 2016): 186–93. http://dx.doi.org/10.1016/j.egypro.2016.10.050.

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Magoba, Moses, and Mimonitu Opuwari. "Petrophysical interpretation and fluid substitution modelling of the upper shallow marine sandstone reservoirs in the Bredasdorp Basin, offshore South Africa." Journal of Petroleum Exploration and Production Technology 10, no. 2 (November 7, 2019): 783–803. http://dx.doi.org/10.1007/s13202-019-00796-1.

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Abstract The fluid substitution method is used for predicting elastic properties of reservoir rocks and their dependence on pore fluid and porosity. This method makes it possible to predict changes in elastic response of a rock saturation with different fluids. This study focused on the Upper Shallow Marine sandstone reservoirs of five selected wells (MM1, MM2, MM3, MM4, and MM5) in the Bredasdorp Basin, offshore South Africa. The integration of petrophysics and rock physics (Gassmann fluid substitution) was applied to the upper shallow marine sandstone reservoirs for reservoir characterisation. The objective of the study was to calculate the volume of clay, porosity, water saturation, permeability, and hydrocarbon saturation, and the application of the Gassmann fluid substitution modelling to determine the effect of different pore fluids (brine, oil, and gas) on acoustic properties (compressional velocity, shear velocity, and density) using rock frame properties. The results showed average effective porosity ranging from 8.7% to 16.6%, indicating a fair to good reservoir quality. The average volume of clay, water saturation, and permeability values ranged from 8.6% to 22.3%, 18.9% to 41.6%, and 0.096–151.8 mD, respectively. The distribution of the petrophysical properties across the field was clearly defined with MM2 and MM3 revealing good porosity and MM1, MM4, and MM5 revealing fair porosity. Well MM4 revealed poor permeability, while MM3 revealed good permeability. The fluid substitution affected rock property significantly. The primary velocity, Vp, slightly decreased when brine was substituted with gas in wells MM1, MM2, MM3, and MM4. The shear velocity, Vs, remained unaffected in all the wells. This study demonstrated how integration of petrophysics and fluid substitution can help to understand the behaviour of rock properties in response to fluid saturation changes in the Bredasdorp Basin. The integration of these two disciplines increases the obtained results’ quality and reliability.

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Blignault, H. J., and J. N. Theron. "Diapirism and the Fold Zone controversy of the Ordovician glaciomarine Pakhuis Formation, South Africa." South African Journal of Geology 120, no. 2 (June 1, 2017): 209–22. http://dx.doi.org/10.25131/gssajg.120.2.209.

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Abstract The Fold Zone controversy centers around firstly, the relationship between the direction of ice-flow and the geometry of the fold structures, and secondly the relative importance of subglacial or proglacial buckling as a folding process compared to the role of load casts or ball-and-pillow structures. The more recent recognition of diapirs associated with the Fold Zone resulted in further field investigations. Understanding the advance-retreat sequence constrains the interpretation of the glaciotectonic processes. The Sneeukop Member, the unconformity and Steenbras Member are interpreted as a continuum ice-expansion sequence without a major retreat interlude. The palaeo-ice-flow data are reinterpreted to accommodate the regional variation of ice-flow patterns. It is concluded that the Pakhuis ice sheet expansion overriding the Peninsula basin took place by means of tributary troughs converging on the main Peninsula trough thus explaining the relationship between the direction of ice-flow and fold trend variations across the basin. The folds also vary regionally in style between upright and overturned. Diapirs were recognized both as blind mushroom structures below the unconformity and piercing upwards. Chaotic breccias and lit-par-lit intermixing of tillite and deformed, attenuated banded sandstone are interpreted as blowout material presumably formed by a piercement diapir venting at the surface. Diapirism in the Pakhuis glacial context is understood as the consequence of an ice sheet expansion over a water-logged Peninsula sand aquifer. The over-pressurized sand aquifer gave rise to diapirs and associated structures. The main features of the Fold Zone are compared to modern examples as described in the literature. Push moraine and crevasse-filling examples are considered as the best-fit models to explain the genesis of the Fold Zone.

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Reimann, S., C. E. Heubeck, P. Fugmann, D. J. Janse van Rensburg, A. Zametzer, S. H. Serre, and T. B. Thomsen. "Syndepositional hydrothermalism selectively preserves records of one of the earliest benthic ecosystems, Moodies Group (3.22 Ga), Barberton Greenstone Belt, South Africa." South African Journal of Geology 124, no. 1 (March 1, 2021): 253–78. http://dx.doi.org/10.25131/sajg.124.0012.

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Abstract The ~3.22 Ga Moodies Group, Barberton Greenstone Belt (BGB), South Africa, provides a unique window into Archaean sedimentary, magmatic and ecological processes. In the central BGB, a regional mafic complex, consisting of a genetically related major mafic sill, a peperitic dyke stockwork, and extensive basaltic lava flows affected thick quartzose sandstones of the Moodies Group. We argue that epithermal hydrothermalism associated with this magmatic event occurred, at least in part, syndepositionally and in places destroyed, in other places preserved the abundant benthic microbial mats in terrestrial- and coastal-facies sandstone of this unit. We differentiate four principal types of hydrothermal alteration: (1) Sericitization resulted from ubiquitous feldspar breakdown; (2) iron-oxide alteration replaced the original matrix by fine-grained iron oxide; (3) silicification replaced matrix and most non-silica grains by microcrystalline silica and locally preserved kerogenous microbial mats; and (4) hydraulic fracturing at shallow depth brecciated consolidated Moodies Group sandstone and created closely spaced, randomly oriented fractures and quartz-filled veins. Because stockwork intrusion locally interacted with unconsolidated water-saturated sediment and because the dykes connect the sill with the mafic lava but also follow zones of structural weakness, we suggest that hydrothermalism associated with this magmatic event occurred syndepositionally but was also – within the resolution of radiometric age data – contemporaneous with tight regional folding. We conclude that microbial organisms in Paleoarchaean coastal (tidal, estuarine) environments may have been formerly widespread, possibly even abundant, but are nearly nowhere preserved because they were easily degradable. Preservation of Early Archaean microbial mats in a thermal aureole in the central BGB was controlled by the “just right” degree of heating and very early hydrothermal silicification.

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Journal articles on the topic 'Sandton (South Africa)'

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