Bibliografie tematiche / Transvaal Supergroup (South Africa)

Indice

Articoli di riviste
Tesi
Libri
Capitoli di libri
Atti di convegni

Letteratura scientifica selezionata sul tema "Transvaal Supergroup (South Africa)"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 13 febbraio 2022

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili

Scegli il tipo di fonte:

Consulta la lista di attuali articoli, libri, tesi, atti di convegni e altre fonti scientifiche attinenti al tema "Transvaal Supergroup (South Africa)".

Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.

Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.

Articoli di riviste sul tema "Transvaal Supergroup (South Africa)"

Buick, I. S., R. Uken, R. L. Gibson e T. Wallmach. "High-δ13C Paleoproterozoic carbonates from the Transvaal Supergroup, South Africa". Geology 26, n. 10 (1998): 875. http://dx.doi.org/10.1130/0091-7613(1998)026<0875:hcpcft>2.3.co;2.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Moore, John M., Harilaos Tsikos e Stefane Polteau. "Deconstructing the Transvaal Supergroup, South Africa: implications for Palaeoproterozoic palaeoclimate models". Journal of African Earth Sciences 33, n. 3-4 (gennaio 2001): 437–44. http://dx.doi.org/10.1016/s0899-5362(01)00084-7.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Button, A., e R. G. Cawthorn. "Distribution of mafic sills in the Transvaal Supergroup, northeastern South Africa". Journal of the Geological Society 172, n. 3 (19 marzo 2015): 357–67. http://dx.doi.org/10.1144/jgs2014-101.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Lenhardt, N., W. Altermann, F. Humbert e M. de Kock. "Lithostratigraphy of the Palaeoproterozoic Hekpoort Formation (Pretoria Group, Transvaal Supergroup), South Africa". South African Journal of Geology 123, n. 4 (1 dicembre 2020): 655–68. http://dx.doi.org/10.25131/sajg.123.0043.

Testo completo

Abstract (sommario):

Abstract The Palaeoproterozoic Hekpoort Formation of the Pretoria Group is a lava-dominated unit that has a basin-wide extent throughout the Transvaal sub-basin of South Africa. Additional correlative units may be present in the Kanye sub-basin of Botswana. The key characteristic of the formation is its general geochemical uniformity. Volcaniclastic and other sedimentary rocks are relatively rare throughout the succession but may be dominant in some locations. Hekpoort Formation outcrops are sporadic throughout the basin and mostly occur in the form of gentle hills and valleys, mainly encircling Archaean domes and the Palaeoproterozoic Bushveld Complex (BC). The unit is exposed in the western Pretoria Group basin, sitting unconformably either on the Timeball Hill Formation or Boshoek Formation, which is lenticular there, and on top of the Boshoek Formation in the east of the basin. The unit is unconformably overlain by the Dwaalheuwel Formation. The type-locality for the Hekpoort Formation is the Hekpoort farm (504 IQ Hekpoort), ca. 60 km to the west-southwest of Pretoria. However, no stratotype has ever been proposed. A lectostratotype, i.e., the Mooikloof area in Pretoria East, that can be enhanced by two reference stratotypes are proposed herein. The Hekpoort Formation was deposited in a cratonic subaerial setting, forming a large igneous province (LIP) in which short-termed localised ponds and small braided river systems existed. It therefore forms one of the major Palaeoproterozoic magmatic events on the Kaapvaal Craton.

Gli stili APA, Harvard, Vancouver, ISO e altri

Eriksson, P. G., e W. Altermann. "An overview of the geology of the Transvaal Supergroup dolomites (South Africa)". Environmental Geology 36, n. 1-2 (20 novembre 1998): 179–88. http://dx.doi.org/10.1007/s002540050334.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Knoll, Andrew H., e Nicolas J. Beukes. "Introduction: Initial investigations of a Neoarchean shelf margin-basin transition (Transvaal Supergroup, South Africa)". Precambrian Research 169, n. 1-4 (marzo 2009): 1–14. http://dx.doi.org/10.1016/j.precamres.2008.10.009.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Sumner, Dawn Y., e Samuel A. Bowring. "UPb geochronologic constraints on deposition of the Campbellrand Subgroup, Transvaal Supergroup, South Africa". Precambrian Research 79, n. 1-2 (luglio 1996): 25–35. http://dx.doi.org/10.1016/0301-9268(95)00086-0.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Hartzer, F. J. "Transvaal Supergroup inliers: geology, tectonic development and relationship with the Bushveld complex, South Africa". Journal of African Earth Sciences 21, n. 4 (novembre 1995): 521–47. http://dx.doi.org/10.1016/0899-5362(95)00108-5.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Schroder, S. "Stratigraphic and geochemical framework of the Agouron drill cores, Transvaal Supergroup (Neoarchean-Paleoproterozoic, South Africa)". South African Journal of Geology 109, n. 1-2 (1 giugno 2006): 23–54. http://dx.doi.org/10.2113/gssajg.109.1-2.23.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Smith, Albertus J. B., e Nicolas J. Beukes. "Palaeoproterozoic banded iron formationhosted high-grade hematite iron ore deposits of the Transvaal Supergroup, South Africa". Episodes 39, n. 2 (1 giugno 2016): 269–84. http://dx.doi.org/10.18814/epiiugs/2016/v39i2/95778.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Più fonti

Tesi sul tema "Transvaal Supergroup (South Africa)"

Bartman, R. D. (Reynard Dirk). "Geology of the Palaeoproterozoic Daspoort Formation (Pretoria Group, Transvaal Supergroup), South Africa". Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/42447.

Testo completo

Abstract (sommario):

This thesis examines the geology of the Daspoort Formation (Pretoria Group, Transvaal Supergroup) of South Africa, with the accent on describing and interpreting its sedimentology. The Palaeoproterozoic Daspoort Formation (c. 2.1‐2.2 Ga) forms part of the Pretoria Group on the Kaapvaal craton. This sandstone‐ and quartzite‐dominated lithological formation covers an elliptical geographical area stretching from the Botswana border in the west to the Drakensberg escarpment in the east, with its northern limit in the Mokopane (Potgietersrus) area and Pretoria in the south; altered outliers are also found in the overturned units of the Vredefort dome in the Potchefstroom area. Deposition of the Daspoort Formation was in a postulated intracratonic basin which applies equally to the entire Transvaal Supergroup succession in the Transvaal depository. Various characteristics from the formation, such as sedimentary architectural elements (e.g., channel–fills etc.), maturity trends and distribution of lithofacies assemblages across the preserved basin give insight into the developing conditions during deposition and genesis of the Daspoort Formation. Subordinate evidence from basic geochemistry, ripple mark data and optical microscope petrology studies support the sedimentary setting inferred for this Palaeoproterozoic deposit. Fluvial and epeiric marine conditions prevailed during the deposition of the Daspoort clastic sediments into the intracratonic basin. This shallow epeiric sea was fed by fluvial influx, predominantly from the west when a transgressive regional systems tract led to the filling of the basin, evolving into the deeper marine Silverton Formation setting, laid down above the Daspoort. Transgression from the east (marine facies predominate) to the west (fluvial facies) is supported by cyclical trends, palaeoenvironmental and palaeogeographical interpretations. Accompanying poorly preserved microbial mat features contribute to the postulated shallow marine environment envisaged for the eastern part of the basin whereas ripple marks and grain size distribution support a fluvial setting for the west, with lithofacies assemblages accounting for both areas’ depositional interpretation.
Dissertation (MSc)--University of Pretoria, 2013.
tm2014
Geology
Unrestricted

Gli stili APA, Harvard, Vancouver, ISO e altri

Polteau, Stéphane. "Stratigraphy and geochemistry of the Makganyene formation, Transvaal supergroup, Northern Cape, South Africa". Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1005616.

Testo completo

Abstract (sommario):

The Makganyene Formation forms the base of the Postmasburg Group in the Transvaal Supergroup of the Northern Cape Province. The Makganyene Formation has diamictite as the main rock type, but siltstone, sandstone, shale, and iron-formations are also present. A glacial origin has been proposed in the past due to the presence of dropstones, faceted and striated pebbles. Typically, the Makganyene Formation contains banded iron-formations interbedded with clastic rocks (shale, siltstone, sandstone and diamictites) at the contact with the underlying iron-formations. This transitional zone is generally overlain by massive or layered diamictites which contain poorly sorted clasts (mainly chert) within a shaly matrix. Striated pebbles have been found during field work, and dropstones have been observed in diamictites and banded iron-formations during the study. The top of the Makganyene Formation contains graded cycles interbedded with diamictites and thin layers of andesitic lavas from the Ongeluk Formation. The basal contact of the Makganyene Formation with the underlying Koegas Subgroup was described as unconformable by previous workers. However field work localised in the Rooinekke area shows a broadly conformable and interbedded contact with the underlying Koegas Subgroup. As described above, banded iron-formations are interbedded with the clastic rocks of the Makganyene Formation. Moreover, boreholes from the Sishen area display the same interbedding at the base of the Makganyene Formation. This suggests that no significant time gap is present in the whole succession between the Ghaap and Postmasburg Group. The Transvaal Supergroup in the Northern Cape displays the following succession : carbonates-BIFs-diamictites/ lava-BIFs-carbonates. The Makganyene Formation is thus at the centre of a symmetrical lithologic succession. Bulk rock compositions show that the diamictites have a similar composition to banded iron-formation with regard to their major element contents. Banded iron-formations acted as a source for the diamictites with carbonates and igneous rocks representing minor components. Differences in bulk composition between the Sishen and Matsap areas emphasize that the source of the diamictite was very localised. The Chemical Index of Alteration (CIA) has been calculated, but since the source dominant rock was iron-formation, this index cannot be usefully applied to the diamictites. ACN, A-CN-K, and A-CNK-FM diagrams confer a major importance in sorting processes due to the separation between the fine and coarse diamictites. The interbedded iron-formations display little clastic contamination indicating deposition in clear water conditions. However, dropstones are present in one borehole from the Matsap area, indicating that iron-formation took place under ice cover, or at least under icebergs. Stable isotope studies show that the iron-formations, interbedded towards the base of the Makganyene Formation, have similar values to the iron-formations of the Koegas Subgroup. As a result of the above observations, new correlations are proposed in this study, relating the different Transvaal Supergroup basins located on the Kaapvaal Craton. The Pretoria Group of the Transvaal Basin has no correlative in the Griqualand West Basin, and the Postmasburg Group of the Northern Cape Basin has no lateral equivalent in the Transvaal Basin. These changes have been made to overcome problems present in the current correlations between those two basins. The Makganyene Formation correlates with the Huronian glaciations which occurred between 2.4 and 2.2 Ga ago in North America. Another Precambrian glaciation is the worldwide and well-studied Neoproterozoic glaciation (640 Ma). At each of these glaciations, major banded iron-formation deposition took place with associated deposition of sedimentary manganese in post-glacial positions. The central position of the Makganyene Formation within the Transvaal Supergroup in the Northern Cape emphasizes this glacial climatic dependence of paleoproterozoic banded iron-formation and manganese deposition. However these two Precambrian glaciations are interpreted in paleomagnetic studies as having occurred near to the equator. The controversial theory of the Snowball Earth has been proposed which proposes that the Earth was entirely frozen from pole to pole. Results from field work, sedimentology, petrography and geochemistry were integrated in a proposed depositional model of the Makganyene Formation occurring at the symmetrical centre of the lithologic succession of the Transvaal Supergroup. At the beginning of the Makganyene glaciation, a regression occurred and glacial advance took place. The diamictites are mostly interpreted as being deposited from wet-based glaciers, probably tidewater glaciers, where significant slumping and debris flows occurred. Any transgression would cause a glacial retreat by rapid calving, re-establishing the chemical sedimentation of banded iron-formations. These sea-level variations are responsible for the interbedding of these different types of rocks (clastic and chemical). The end of the Makganyene glacial event is characterised by subaerial eruptions of andesitic lava of the Ongeluk Formation bringing ashes into the basin. Banded iron-formation and associated manganese accumulations are climate-dependant. Glacial events are responsible for the build up of metallic ions such as iron and manganese in solution in deep waters. A warmer climate would induce a transgression and precipitation of these metallic ions when Eh conditions are favourable. In the Transvaal Supergroup, the climatic variations from warm to cold, and cold to warm are expressed by the lithologic succession. The warm climates are represented by carbonates. Cold climates are represented by banded iron-formations and the peak in cold climate represented by the diamictites of the Makganyene Formation. These changes in climate are gradual, which contradict the dramatic Snowball Earth event: a rapid spread of glaciated areas over low-latitudes freezing the Earth from pole-to-pole. Therefore, to explain low-latitude glaciations at sea-level, a high obliquity of the ecliptic is most likely to have occurred. This high obliquity of the ecliptic was acquired at 4.5 Ga when a giant impactor collided into the Earth to form the Moon. Above the critical value of 54° of the obliquity of the ecliptic, normal climatic zonation reverts, and glaciations will take place preferentially at low-latitudes only when favourable conditions are gathered (relative position ofthe continents and PC02 in the atmosphere).

Gli stili APA, Harvard, Vancouver, ISO e altri

Rafuza, Sipesihle. "Carbonate petrography and geochemistry of BIF of the Transvaal supergroup : evaluating the potential of iron carbonates as proxies for palaeoproterozoic ocean chemistry". Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1018611.

Testo completo

Abstract (sommario):

The subject of BIF genesis, particularly their environmental conditions and ocean chemistry at the time of deposition and their evolution through time, has been a subject of much contentiousness, generating a wealth of proposed genetic models and constant refinements thereof over the years. The prevailing paradigm within the various schools of thought, is the widespread and generally agreed upon depositional and diagenetic model(s) which advocate for BIF deposition under anoxic marine conditions. According to the prevailing models, the primary depositional environment would have involved a seawater column whereby soluble Fe²⁺ expelled by hydrothermal activity mixed with free O₂ from the shallow photic zone produced by eukaryotes, forming a high valence iron oxy-hydroxide precursor such as FeOOH or Fe(OH)₃. An alternative biological mechanism producing similar ferric precursors would have been in the form of photo-ferrotrophy, whereby oxidation of ferrous iron to the ferric form took place in the absence of biological O₂ production. Irrespective of the exact mode of primary iron precipitation (which remains contentious to date), the precipitated ferric oxy-hydroxide precursor would have reacted with co-precipitated organic matter, thus acting as a suitable electron acceptor for organic carbon remineralisation through Dissimilatory Iron Reduction (DIR), as also observed in many modern anoxic diagenetic environments. DIR-dominated diagenetic models imply a predominantly diagenetic influence in BIF mineralogy and genesis, and use as key evidence the low δ¹³C values relative to the seawater bicarbonate value of ~0 ‰, which is also thought to have been the dissolved bicarbonate isotope composition in the early Precambrian oceans. The carbon for diagenetic carbonate formation would thus have been sourced through a combination of two end-member sources: pore-fluid bicarbonate at ~0 ‰ and particulate organic carbon at circa -28 ‰, resulting in the intermediate δ¹³C values observed in BIFs today. This study targets 65 drillcore samples of the upper Kuruman and Griquatown BIF from the lower Transvaal Supergroup in the Hotazel area, Northern Cape, South Africa, and sets out to explore key aspects in BIF carbonate petrography and geochemistry that are pertinent to current debates surrounding their interpretation with regard to primary versus diagenetic processes. The focus here rests on applications of carbonate (mainly siderite and ankerite) petrography, mineral chemistry, bulk and mineral-specific carbon isotopes and speciation analyses, with a view to obtaining valuable new insights into BIF carbonates as potential records of ocean chemistry for their bulk carbonate-carbon isotope signature. Evaluation of the present results is done in light of pre-existing, widely accepted diagenetic models against a proposed water-column model for the origin of the carbonate species in BIF. The latter utilises a combination of geochemical attributes of the studied carbonates, including the conspicuous Mn enrichment and stratigraphic variability in Mn/Fe ratio of the Griquatown BIF recorded solely in the carbonate fraction of the rocks. Additionally, the carbon isotope signatures of the Griquatown BIF samples are brought into the discussion and provide insights into the potential causes and mechanisms that may have controlled these signatures in a diagenetic versus primary sedimentary environment. Ultimately, implications of the combined observations, findings and arguments presented in this thesis are presented and discussed with particular respect to the redox evolution and carbon cycle of the ocean system prior to the Great Oxidation Event (GOE). A crucial conclusion reached is that, by contrast to previously-proposed models, diagenesis cannot singularly be the major contributing factor in BIF genesis at least with respect to the carbonate fraction in BIF, as it does not readily explain the carbon isotope and mineral-chemical signatures of carbonates in the Griquatown and uppermost Kuruman BIFs. It is proposed instead that these signatures may well record water-column processes of carbon, manganese and iron cycling, and that carbonate formation in the water column and its subsequent transfer to the precursor BIF sediment constitutes a faithful record of such processes. Corollary to that interpretation is the suggestion that the evidently increasing Mn abundance in the carbonate fraction of the Griquatown BIF up-section would point to a chemically evolving depositional basin with time, from being mainly ferruginous as expressed by Mn-poor BIFs in the lower stratigraphic sections (i.e. Kuruman BF) to more manganiferous as recorded in the upper Griquatown BIF, culminating in the deposition of the abnormally enriched in Mn Hotazel BIF at the stratigraphic top of the Transvaal Supergroup. The Paleoproterozoic ocean must therefore have been characterised by long-term active cycling of organic carbon in the water column in the form of an ancient biological pump, albeit with Fe(III) and subsequently Mn(III,IV) oxy-hydroxides being the key electron acceptors within the water column. The highly reproducible stratigraphic isotope profiles for bulk δ¹³C from similar sections further afield over distances up to 20 km, further corroborate unabatedly that bulk carbonate carbon isotope signatures record water column carbon cycling processes rather than widely-proposed anaerobic diagenetic processes.

Gli stili APA, Harvard, Vancouver, ISO e altri

Warke, Matthew. "Stratigraphic and geochemical framework of the Palaeoproterozoic rise in atmospheric oxygen, Transvaal Supergroup (South Africa)". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/stratigraphic-and-geochemical-framework-of-the-palaeoproterozoic-rise-in-atmospheric-oxygen-transvaal-supergroup-south-africa(b0aa0021-946c-4f01-bf4e-297611aa2ec1).html.

Testo completo

Abstract (sommario):

The Transvaal Supergroup (South Africa) records evidence of trace oxygen production in late Neoarchaean strata, approximately 200 million years before the 'Great Oxidation Event' (GOE) which is recorded within the Palaeoproterozoic Duitschland Formation (Transvaal Supergroup) between ~2.42 and 2.32 Ga. It is hypothesized that there was a secular rise in oxygen concentrations between the late Neoarchaean and the GOE which may be recorded within the 'mid-Transvaal' Supergroup (Tongwane Formation, Duitschland Formation, Koegas Subgroup). This project has integrated field sedimentology, petrography and geochemistry to build new or revised depositional and diagenetic frameworks for each of these successions and has assessed palaeoredox conditions using carbon isotopes and rare earth element and yttrium (REY) patterns and anomalies. Despite a complex paragenetic history, including medium-grade contact metamorphism, the Tongwane Formation preserves primary (or near-primary), carbon isotope (delta13Ccarb = ~0 ± 2 ‰VPDB) and REY patterns that are consistent with Palaeoproterozoic seawater. No anomalously positive delta13Ccarb values or cerium (CeSN) anomalies are preserved, suggesting limited build-up of free O2. The lower Duitschland Formation preserves previously undocumented lithofacies variations and an angular mid-Duitschland unconformity (which is contemporaneous with the GOE). A new depositional model is proposed; facies assemblages and geometries are consistent with deposition of a wave-influenced Gilbert fan delta deposited in an isolated depocentre created by localised extensional fault subsidence. Lower Duitschland Formation limestones and dolomites show depleted delta13Ccarb and delta18Ocarb values and marine REY patterns which lack CeSN anomalies. Negative delta13Ccarb values suggest incorporation of 12C from organic matter during early diagenesis. There is no evidence of significant free oxygen production. The Koegas Subgroup is unconformably overlain by glacial strata of the Postmasburg Subgroup; the two successions are not intercalated and therefore not synchronous. Marine REY signals with positive Ce anomalies are recorded in delta13Ccarb depleted, stromatolitic dolomite exposed on the farms Taaibosfontein and Sandridge. Small magnitude positive anomalies are likely calculation artefacts, though anomalies >30 % may reflect redox stratification. Neoarchaean cuspate stromatolites of the Gamohaan Formation record trace element distributions - imaged using synchrotron-based XRF techniques - that map to primary microbial structures are not attributable to syndepositional or diagenetic mineralisation processes. Thus they may prove to be indicators of specific microorganisms and metabolic processes, e.g. photosynthetically relevant metals (e.g. Mn, Cu, Ni) mapped in biogenic structures may serve as a 'fingerprint' of cyanobacterial oxygenic photosynthesis. Overall, no evidence is seen for a secular rise in oxygen in the mid-Transvaal. However, depositional frameworks and diagenetic processes have been determined and the retention of marine signals established within the Tongwane, Duitschland and Koegas successions. Therefore the findings of this project constitute a robust framework for future palaeoredox studies of the mid-Transvaal Supergroup.

Gli stili APA, Harvard, Vancouver, ISO e altri

Fryer, Lindi. "Controls on the distribution of manganese in banded iron-formations (BIF) of the palaeoproterozoic transvaal supergroup, South Africa". Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/2926.

Testo completo

Abstract (sommario):

The 2.65 to 2.05 Ga Transvaal Supergroup comprises one of the best-preserved and largely continuous successions in the world of Banded Iron-Formation (BIF), a chemical sedimentary rock composed of fine (mm to cm scale) interbanded iron-rich and iron-poor bands, developed atop the Archaean Kaapvaal Craton of southern Africa. The Transvaal BIF sequence contains at its upper stratigraphic part, an intriguing interlayered BIF-Mn association, namely the Hotazel Formation in the Kalahari Manganese Field, which constitutes the largest land-based manganese deposit on record. The genesis of the Hotazel deposits, and their exact significance in terms of atmosphere-hydrosphere-biosphere evolution, remain as elusive as they are challenging. In this thesis, an attempt is made to illuminate the origin and diagenesis of the Hotazel Formation and its post-depositional hydrothermal modification, through a highresolution geochemical study of the narrowest of the three BIF-Mn sedimentary cycles present in the Hotazel stratigraphy. This approach is coupled with a preliminary geochemical study of the distribution of Mn in older BIF of the Transvaal Supergroup as well (Kuruman and Griquatown Formations), so as to test recent models that causally link all BIFs in the Transvaal Supergroup under a common and evolving palaeo-environment of deposition. The results indicate that the cyclic deposition of the Hotazel BIF and enveloped Mn-rich sediments would have taken place in a stratified basin with a well-developed chemocline in terms of the vertical distributions of Mn and Fe, much like recent anoxic stratified basins such as the Orca Basin in the Gulf of Mexico. The increased Mn abundances as Mn-bearing ferrous carbonates in the upper part of the Griquatown BIF predating the Hotazel strata, also seems to lend support to the notion that the two BIFs are temporally interlinked as part of a broader sedimentary continuum. Finally, the largely conservative behaviour of Mn and associated elements during hydrothermal alteration of the Hotazel rocks is re-assessed, and renewed emphasis is placed on the possibility that brine metasomatism may have been a key factor in Mn redistribution and residual enrichment.

Gli stili APA, Harvard, Vancouver, ISO e altri

Sumner, Dawn Yvonne 1966. "Facies, paleogeography, and the carbonate precipitation on the archean (2520 Ma) Campbellrand-Malmani carbonate platform, Transvaal supergroup, South Africa". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/57758.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Okafor, O. J. "Comparison of microbially induced sedimentary structures in the Palaeoproterozoic Magaliesberg (Transvaal Supergroup) and Makgabeng (Waterberg Group) Formations, Kaapvaal craton, South Africa". Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/45922.

Testo completo

Abstract (sommario):

The MRS/MISS of the Makgabeng Formation encompasses sand cracks, wrinkle marks, mat fragments, mat chips and roll-ups and those of the Magaliesberg formation are wrinkle marks, petees/petee ridges, sand cracks, and multi-directional ripples. The sedimentary process that moderated the formational mechanism of the MISS of the Makgabeng Formation is (descriptively allochthonous) of high energy (inter-dune depositional setting) that eroded, transported and re-deposited mat bound sediments. The genetic mechanism of the MISS of the Magaliesberg Formation is descriptively authochthonous because of enhanced resistance of biostabilized sediments to being reworked. XRF (major and trace) and XRD analysis (qualitative and quantitative) was done on MISS bearing sedimentary rock layers (A) and underlying sedimentary sections (B) of Magaliesberg and Makgabeng samples. Result show high quartz content of all the analyzed samples compared to average sandstones. This premise suggests a relation of microbes (e.g. cyanobacteria) to phototrophy and/photoautotrophy because of the conduction properties of translucent quartz. Also plausible inference is that the intense chemical weathering that produced the quartz arenite was positively influenced by microbes, as noted in some Proterozoic basins. There is higher concentration of Ba in all A samples compared to B (Makgabeng and Magaliesberg) which might be emblematic of biogenicity. The Magaliesberg analyzed samples (MAG 101, 102, 103) exhibit homogeneity by the higher concentration of Al2O3, TiO2, K2O, and P2O5, and lower concentration of SiO2 in the A compared to the B subsamples of a particular sample. Also, Magaliesberg analyzed samples (MAG 101, 102, 103) exhibit homogeneity by the lower concentration of quartz and higher concentration of muscovite in the A compared to the B subsamples. This exact established negative correlation between the duo of SiO2 and quartz, and the quartet of Al2O3, TiO2, K2O, and P2O5, and muscovite as in Magaliesberg samples pertains also to a Makgabeng sample (MKG 102; roll-up). MKG 101 (mat fragment) deviates from this mineralogical and geochemical trend. Each of the A samples of MAG 101, 102, 103, are uniformly of higher concentration in Ce, Cr, Nb, Th, V, Y, Zn, Zr compared to the B version of that sample. MKG 101 and 102 are uniformly of lower concentration of Ce, Cr, Nb, Th, V, Y, Zn, Zr in A compared to the B version of that sample. The A of each of the samples MAG 101, 102, and 103 has higher concentration of Hf and Rb compared to its B; a character that is also exhibit in MKG 102, and MKG 101 is vice versa. Microscopy shows that A of all the samples is of smaller grain size compared to B, espousing affinity of microbes to fine-medium grained sandstones. Microscopy of the Magaliesberg Formation samples show Pseudo petee ridges and pseudo cross lamination which reflect biostabilization, and microscopy of the Makgabeng Formation show roll-ups, mat chips and composite mat chips. The MISS genetic difference of the two formations is related to energy, water residence time (emergence and inundation), Ph, and similarity is related to mutuality in shallow water environment. Mat types are inferred to be biologically, physically and chemically moderated adaptations of microbial communities to specific cum peculiar locally prevailing environmental conditions; factors that are premised on taphonomy and ecology.
Dissertation (MSc)--University of Pretoria, 2014.
tm2015
Geology
MSc
Unrestricted

Gli stili APA, Harvard, Vancouver, ISO e altri

Li, Na. "Textural and Rule-based Lithological Classification of Remote Sensing Data, and Geological Mapping in Southwestern Prieska Sub-basin, Transvaal Supergroup, South Africa". Diss., lmu, 2010. http://edoc.ub.uni-muenchen.de/11824/2/Li_Na.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Moloto, William. "A bulk and fraction-specific geochemical study of the origin of diverse high-grade hematitic iron ores from the Transvaal Supergroup, Northern Cape Province, South Africa". Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/50546.

Testo completo

Abstract (sommario):

The Paleoproterozoic Transvaal Supergroup in the Northern Cape Province of South Africa is host to high-grade, Banded Iron Formation-hosted hematite iron-ore deposits and is the country’s most important source of iron to date. Previous studies suggest the origin of these iron ores to be ancient supergene, and that the ore forming process would have therefore pre-dated deposition of the basal Mapedi shales of the Olifansthoek Supergroup that unconformably overlies the Transvaal strata. The nature of the protolith to the ores has been suggested to be largely BIF of the Asbestos Hills Subgroup, and mainly the Kuruman BIF. The work presented in this thesis seeks to provide insights into the diversity of processes that are likely to have been involved during the genesis of these high-grade iron ores, in the context of constraining the pre-ore lithologies and the relative role of supergene-style, largely residual enrichment processes versus any possible metasomatic hydrothermal effects. This study had as primary focus the application of combined bulk and fraction-specific geochemical applications on representative iron-ore samples from four different localities in the Northern Cape Province, namely King/Khumani, Beeshoek, Heuninkranz and Hotazel. The collected samples show a variety of textures and also capture different pre-unconformity stratigraphic sections of BIF. The key objective was to assess whether the fraction-specific analytical results could provide any firm constraints for the origin of the ferrous and non-ferrous matrix fractions of the ores, namely whether they represent any combinations of protolith residue, allochtonously-introduced detritus or hydrothermally-derived material, and whether the results are comparable and consistent across all samples studied. In particular, constraints were sought as to whether the ore protolith was exclusively BIF or may potentially have contained at least a fraction of other lithologic types, such as shale; and whether there is sufficient evidence to support solely a supergene model for the ores or the data suggest other more epigenetic models of ore formation involving the action of hydrothermal fluids Bulk-rock geochemical analyses reveal the overwhelming dominance of Fe-oxide (as hematite) in all samples, at concentrations as high as 99 wt.% Fe2O3. Major and trace-element abundances of all samples were re-calculated assuming only iron addition from the postulated protolith (average BIF and shale), and the results revealed atypical enrichments in the iron ores by comparison to average BIF, and more shale-like relative abundances when normalised against the Post-Archaean Average Shale (PAAS). Specifically, BIF-normalised diagrams show relative enrichments by as much as 53-95% for Al2O3; 11-86% for TiO2; and 4-60% for P2O5. By contrast, PAAS-normalised values display enrichments of 1-3% for Al2O3, 0.2-3% for TiO2, and 3-13% for P2O5. Similar observations can be made for the greatest majority of trace elements when normalised against average BIF as compared to normalisation against PAAS. A suite of trace element that include alkali earths (e.g. Ba, Sr) and transition metals (e.g. Ni, Zn) show enrichments that are unrelated to the apparently detrital siliciclastic fraction of the ores, and are therefore linked to a possible hydrothermal input. Fraction-specific extractions were performed via the adaptation of existing dissolution protocols using oxalic acid (iron-oxide fraction) followed by HF digestion (silicate-fraction). The analyses of the produced aliquots using ICP-MS techniques, focused mainly on the REE abundances of the separated ferrous and non-ferrous matrix fractions and their comparisons to bulk-rock REE signatures. The results lend further support to the suggestion that the ore samples contain a predominant shale-like signal which does not directly compare to published REE signatures for supergene or hydrothermal BIF-hosted iron-ore deposits alike. The data therefore collectively point to a post-unconformity epigenetic hydrothermal event/s of iron ore-formation that would have exploited not only BIF but also shale as suitable pre-ore protolith.

Gli stili APA, Harvard, Vancouver, ISO e altri

Oonk, Paul Bernardus Hendrikus. "Fraction-specific geochemistry across the Asbestos Hills BIF of the Transvaal Supergroup, South Africa: implications for the origin of BIF and the history of atmospheric oxygen". Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/50721.

Testo completo

Abstract (sommario):

Banded iron formations (BIF), deposited prior to and concurrent with the Great Oxidation Event (GOE) at ca. 2.4 Ga, record changes in oceanic and atmospheric chemistry during this critical time interval. Four previously unstudied drill-cores from the Griqualand West Basin, South Africa, capturing the rhythmically mesobanded, deep-water Kuruman BIF and the overlying granular, shallower Griquatown BIF, were sampled every ca. 10 m along core depth. Mineralogically, these BIFs consist of three iron-bearing fractions: (1) Fe-Ca-Mg-Mn carbonates, (2) magnetite with/without minor hematite and (3) Fe-silicates. These fractions are typically fine-grained on a sub-μm scale and their co-occurrence in varying amounts means that bulk-rock or microanalytical geochemical and stable isotope data are influenced by mineralogy.

Gli stili APA, Harvard, Vancouver, ISO e altri

Più fonti

Libri sul tema "Transvaal Supergroup (South Africa)"

Tyler, N. 2200Ma-Old "trace fossils" from the Transvaal Supergroup in the Transvaal. Johannesburg: University of the Witwatersrand, 1986.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Creswicke, Louis. South Africa and the Transvaal war. Toronto: Publisher's Syndicate, 1993.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Mitchell, James H. Tartan on the veld: The Transvaal Scottish, 1950₋1993. Johannesburg: Transvaal Scottish Regimental Council, 1994.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Hendriks, P. G. Waai, vierkleur van Transvaal. Morgenzon: Oranjewerkers Promosies, 1991.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Dorothea Sarah Florence Alexandra Phillips. Some South African recollections. London: Longmans, Green, 1989.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Harley, M. The mineralisation at Elandshoogte Gold Mine, Eastern Transvaal, South Africa. Johannesburg: University of the Witwatersrand, 1990.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Marshall, T. R. The alluvial-diamond fields of the western Transvaal. Johannesburg: Economic Geology Research Unit, University of the Witwatersrand, 1986.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Marshall, T. R. The alluvial-diamond fields of the western Transvaal. Johannesburg: Economic Geology Research Unit, University of the Witwatersrand, 1986.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Funston, Malcolm. Bushveld trees: Lifeblood of the Transvaal lowveld. Vlaeberg: Fernwood Press, 1993.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Sammy Marks: The uncrowned king of the Transvaal. Cape Town: D. Philip, 1991.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Più fonti

Capitoli di libri sul tema "Transvaal Supergroup (South Africa)"

Hofmann, Axel. "Transvaal Supergroup, South Africa". In Encyclopedia of Astrobiology, 1709. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-11274-4_1609.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Hofmann, Axel. "Transvaal Supergroup, South Africa". In Encyclopedia of Astrobiology, 1. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-27833-4_1609-3.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Hofmann, Axel. "Transvaal Supergroup, South Africa". In Encyclopedia of Astrobiology, 1. Berlin, Heidelberg: Springer Berlin Heidelberg, 2020. http://dx.doi.org/10.1007/978-3-642-27833-4_1609-4.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Hofmann, Axel. "Transvaal Supergroup, South Africa". In Encyclopedia of Astrobiology, 2550. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-44185-5_1609.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Bright, Rachel K. "The Transvaal Labour ‘Problem’ and the Chinese Solution". In Chinese Labour in South Africa, 1902–10, 22–37. London: Palgrave Macmillan UK, 2013. http://dx.doi.org/10.1057/9781137316578_3.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Walsh, Maud M., e Frances Westall. "Archean Biofilms Preserved in the Swaziland Supergroup, South Africa". In Fossil and Recent Biofilms, 307–16. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0193-8_20.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Cole, M. M. "The vegetation over mafic and ultramafic rocks in the Transvaal Lowveld, South Africa". In The Ecology of Areas with Serpentinized Rocks, 333–42. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-3722-5_13.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Fröbisch, Jörg. "Synapsid Diversity and the Rock Record in the Permian-Triassic Beaufort Group (Karoo Supergroup), South Africa". In Vertebrate Paleobiology and Paleoanthropology, 305–19. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-6841-3_18.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

MacKenzie, John M., e Nigel R. Dalziel. "Continuing migration to Natal, the Cape and the Transvaal". In The Scots in South Africa. Manchester University Press, 2013. http://dx.doi.org/10.7765/9781847794468.00010.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

MacKenzie, John M., e Nigel R. Dalziel. "Continuing migration to Natal, the Cape and the Transvaal". In The Scots in South Africa, 135–63. Manchester University Press, 2012. http://dx.doi.org/10.7228/manchester/9780719076084.003.0005.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Atti di convegni sul tema "Transvaal Supergroup (South Africa)"

Dowdy, T., L. C. Kah, W. Altermann e J. H. Alexander. "EXPLORATION OF POTENTIAL SEISMITES: ARCHEAN NAUGA FORMATION, TRANSVAAL SUPERGROUP, SOUTH AFRICA". In Joint 69th Annual Southeastern / 55th Annual Northeastern GSA Section Meeting - 2020. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020se-345256.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Thovhogi*, Tshifhiwa, Sean Johnson e Xavier Schalkwyk. "Assessment of the Coal Bed Methane Resource Potential Within Coal-bearing Strata of the Karoo Supergroup, South Africa". In International Conference and Exhibition, Melbourne, Australia 13-16 September 2015. Society of Exploration Geophysicists and American Association of Petroleum Geologists, 2015. http://dx.doi.org/10.1190/ice2015-2211000.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Ünsal, Tuğçe, e Kübra Yazıcı. "The Importance of Gerbera as a Cut Flower and Advances of It in Scientific Research". In International Students Science Congress. Izmir International Guest Student Association, 2021. http://dx.doi.org/10.52460/issc.2021.010.

Testo completo

Abstract (sommario):

Gerbera, a member of the Asteraceae family, has approximately 30 species known in nature. It has spread naturally in South Africa, Africa, Madagascar, and tropical Asia. The first scientific description of gerberas is J.D. Described by Hooker. It is also known as the Transvaal Daisy or Barberton Daisy. It is the second most produced cut flower after carnation as cut flower in our country. We can divide the scientific studies conducted on the gerbera plant into four groups. Studies in general; To produce 1st quality gerbera by providing the growth of plant height, flower diameter and flower stem with growth regulators, to obtain fast and many plants with tissue culture, to bring new products to the product range with breeding studies and to maintain the vitality of the plant in the process from harvest to consumer It is based on increasing the life of the vase and introducing new solutions to the market. This study was conducted to emphasize the importance of Gerbera as a cut flower and its developments in scientific research.

Gli stili APA, Harvard, Vancouver, ISO e altri

Offriamo sconti su tutti i piani premium per gli autori le cui opere sono incluse in raccolte letterarie tematiche. Contattaci per ottenere un codice promozionale unico!