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Sedimentology of the Vaal Reef paleoplacer in the western portion of Vaal Reefs Mine

- Verrezen, Lucien

Method development for the digestion and analysis of four common sedimentary lithologies using ICP-OES and ICP-MS

- Downer, Nicholas Ramsey

  • Authors: Downer, Nicholas Ramsey
  • Date: 2010-03-25T06:44:39Z
  • Subjects: Sedimentology , Inductively coupled plasma spectrometry , Inductively coupled plasma mass spectrometry
  • Type: Thesis
  • Identifier: uj:6701 , http://hdl.handle.net/10210/3103
  • Description: M.Sc. , The understanding of the classification and origin of geological systems is facilitated by the acquisition of accurate and precise analytical data. New instrumentation is rapidly developed for the preparation and quantitative analysis of geological materials using smaller amounts of sample, with lower limits of detection and faster analysis times. The development of new methodologies is crucial for the effective utilisation of new instrumentation. This study was conceptualised because of the relationship between the Department of Geology and the Central Analytical Facility of the Faculty of Science, University of Johannesburg. There is a high demand for accurate and precise chemical data for various lithologies and the availability of high-end analytical equipment, but little practical expertise to utilise this equipment to its full potential. The study is centred round the analysis of four common sedimentary lithological groups that are routinely studied by the Department of Geology namely carbonate rocks, shales, iron ore and manganese ore. A large literature base exists for the decomposition and analysis of geological materials. The bulk of this literature is centred round more established and conventional methods of sample preparation and analysis. The use of microwave digestion instrumentation and methodologies in recent times has revolutionised sample decomposition with shorter decomposition times, smaller sample masses required for decomposition, lower loss of analytes to volatilisation and creating a safer laboratory environment for analysts to work in. Inductively coupled plasma optical emission spectroscopy (ICP-OES) is a more mature method of sample analysis, being commercialised in the mid 1970’s, while inductively coupled plasma mass spectroscopy (ICP-MS) is a newer technique, v being commercialised as of the mid 1980’s. These two techniques are multi-element techniques, with low limits of detection and fast analysis times for a plethora of analytes, over seventy elements for ICP-OES and over eighty elements for ICP-MS. Samples from all four lithological groups were successfully digested in a microwave digestion unit with varying combinations of nitric acid (HNO3), hydrochloric acid (HCl), perchloric acid (HClO4) and hydrofluoric acid (HF) and various digestion programs. Accurate and repeatable methods of analysis were developed for iron, manganese, calcium and potassium for all four lithologies with ICP-OES; aluminium was successfully determined for shale, iron and manganese ore with ICP-OES. Titanium, sodium, arsenic, barium, bismuth, chromium, copper, molybdenum, scandium, strontium and vanadium were determined for all four lithotypes with acceptable accuracy and repeatability using ICP-MS.
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Lithostratigraphy, depositional environments and sedimentology of the Permian Vryheid Formation (Karoo Supergroup), Arnot North, Witbank Coalfield, South Africa

- Uys, Joanne

  • Authors: Uys, Joanne
  • Date: 2009-04-30T09:28:39Z
  • Subjects: Stratigraphic geology , Sedimentology , Facies (Geology) , Lithofacies , Karoo Supergroup , Mpumalanga (South Africa)
  • Type: Thesis
  • Identifier: uj:8338 , http://hdl.handle.net/10210/2464
  • Description: M.Sc. , This work documents the lithostratigraphy and interpreted depositional environments of the Permian Vryheid Formation in the most northern proximal setting yet studied in the Witbank Coalfield. Data from 924 boreholes from two mining companies (Anglo Operations Ltd. and Xstrata Coal Ltd.) drilled over 50 years, covering an area of 910km2 revealed a 35m sequence of terrigenous clastic sedimentary rocks containing two coal seams. These seams are numbered No. 1 at the base and No. 2 at the top. Delineation of facies type, facies assemblages, lateral facies distributions and computer-based three-dimensional modeling facilitated the interpretation of the palaeodepositional environments. Eleven lithofacies are defined and interpreted hydrodynamically. Facies classification is based primarily on grain size and sedimentary structures. The modeling of the borehole information uses the finite element method to interpolate the thickness, roof and floor surfaces and trend of each seam and inter-seam parting between boreholes. The spatial position of the boreholes is defined using a digital terrain model that represents the current surface topography. Lateral distributions were correlated by repositioning the boreholes using the base of the No. 2 seam as a datum. Glaciofluvial, glaciolacustrine, bed-load (braided) fluvial and constructive progradational deltaic environments are interpreted in the study area. Fluvial channel sequences are dominant and cause the thinning of the coal seams below channel axes as well as splitting of both the No. 1 and No. 2 seams. Glaciofluvial influences also affect the lower portion of the No. 1 seam. Basement palaeotopography restricts the distribution of the lower splits of the No. 1 seam. The coals either ‘pinch-out’ or are absent above basement highs but blanket the adjacent low-lying areas. In contrast to the greater Witbank Coalfield, but concurrent with other studies in the more northern proximal regions, fluvial systems dominate over deltaic systems in the study area. Glaciodeltaic, fluviodeltaic and anastomosed channel fluvial systems recognized in the remainder of the Karoo Basin were fed by the braided fluvial systems in the study area. The close proximity of the study area to the northern edge of the basin accounts for the subtle differences in lithostratigraphy and interpreted depositional environments when compared with more distal sites to the south. For example, glaciofluvial clastic sediment input in the lower portions of the No. 1 seam and post-Karoo erosion that has removed the overlying seams; the deltaic progradational sequence, above the No. 2 seam, occurs twice in succession and the bioturbation, that has become characteristic of sedimentary sequence of the Vryheid Formation above the No. 2 seam in the central and southern parts of the Karoo Basin, is not as identifiable. These differences are explained by the extreme proximal location of the study area on the northern basin margin relative to the remainder of the Karoo Basin.
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Die sedimentologie en stratigrafie van die Ecca-Beaufortoorgang in die Noordoostelike gedeelte van die hoof Karookom.

- Muntingh, Dirk Jacobus

  • Authors: Muntingh, Dirk Jacobus
  • Date: 2014-03-27
  • Subjects: Sedimentology , Geology - Cape Province - Karoo Basin. , Geology, Stratigraphic
  • Type: Thesis
  • Identifier: uj:4528 , http://hdl.handle.net/10210/9865
  • Description: M.Sc. (Geology) , The study was undertaken to investigate the stratigraphic and sedimentological character of the transition between the Ecca and Beaufort Groups in the northeastern region of the main Karoo basin. Detailed stratigraphic profiles demonstrate that the transition comprises a regressional sequence of dark basinal shale overlain by sandy delta-lobe deposits. This is overlain by lenticular sandstones and shale representing meandering stream deposits. The deltaic sedimentary rocks vary markedly along strike and record deposition in four different deltaic sUbenvironments, namely: (A) "Normal" central delta lobe areas characterized by distal mouth bar sandstone-shale rhythmites gradationally overlain by proximal distributary mouth bar sandstones. (B) Interdistributary bay areas characterized by stacked thin upward-coarsening shale-sandstone cycles. (C) Areas of strong distributary channel erosion where prodelta shale deposits are erosively overlain by distributary or fluvial channel sandstones. No distributary mouth bar deposits are present. (D) Storm-dominated areas comprising prodelta sedimentary rocks which are in turn overlain by storm and possible barrier sand deposits. Palaeocurrent directions indicate that sediment transport was from the north-west, north and north-east. The concentrations of the trace elements B, V, Zn and Ni in prodelta shales indicate the possible prevalence of both marine and freshwater conditions in the near-coastal waters of the Ecca basin. Lateral variation of depositional environments on the same stratigraphic level makes the placing of the Ecca-Beaufort contact based on genetic criteria unsuitable. It is therefore suggested that purely lithostratigraphic criteria be used. On this basis the Ecca-Beaufort contact is taken at the base of the first prominent sandstone which overlies the Volksrust Shale Formation.
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Die mineralogie en geochemie van sedimentêre siklusse in die Kuruman- en Griquatown-ysterformasies van die Transvaal-Supergroep in Griekwaland-Wes

- Van Wyk, Catharina Johanna

Sedimentologie en palinologie van die permiese Vryheid formasie in die Greenside-steenkoolmyn, Witbank-steenkoolveld, Suid-Afrika

- Venter, Magarietha Elizabeth

Genetiese stratigrafie en sedimentologie van die opeenvolging Karoo in die westelike en noordelike deel van die Waterbergsteenkoolveld

- Siepker, Eugene Heinrich

Die geologie van die Krokodilrivierfragment, Transvaal

- Hartzer, Frederick Johannes

Stratigrafie en sedimentologie van die groep Beaufort in die Noordoos-Vrystaat

- Groenewald, Gideon Hendrik

Geological controls on no. 4 seam roof conditions at New Denmark Colliery, Highveld Coal Field, Karoo Basin, South Africa

- Stanimirovic, Jasmina

  • Authors: Stanimirovic, Jasmina
  • Date: 2009-01-28T09:43:30Z
  • Subjects: Facies (Geology) , Coal , Stratigraphic geology , Sedimentology , Mine roof control , Karoo Supergroup , Mpumalanga (South Africa)
  • Type: Thesis
  • Identifier: uj:14849 , http://hdl.handle.net/10210/1971
  • Description: M.Sc. , The coal-bearing Permian Vryheid Formation of the Ecca Group (Karoo Supergroup) was investigated at New Denmark Colliery, situated in the north east section of the Karoo Basin, South Africa. The lithostratigraphy of the sequence is defined in terms of conventional lithostratigraphic terminology but also by applying detailed genetic stratigraphic schemes that have previously been proposed for the adjacent coalfields. The succession is divided up into depositional sequences named after the underlying and overlying coal seams, the No. 2, 3, 4 and 5 seam sequences. The sedimentary succession was divided up into five facies, namely: conglomerate facies, sandstone facies, interlaminated sandstone-siltstone facies, siltstone facies and coal facies. These were interpreted hydrodynamically. Facies assemblages were then interpreted palaeoenvironmentally. Glacial, fluvial, deltaic and transgressive marine sequences were responsible for forming this sedimentary succession. Attention was then focussed on the main economic No. 4 seam, which is mined underground at the colliery. Detailed subsurface geological cross-sections, core sequences and isopach maps of the No. 4 seam coal and the lithologies above, were used to determine specific aspects of the depositional environment that could contribute to unstable roof conditions above No. 4 seam. Coarsening-upward deltaic cycles, fining-upward bedload fluvial cycles, glauconite sandstone marine transgressions and crevasse-splay deposits are recognized in the overlying strata. Poor roof conditions occur parallel to palaeochannel margins because the interbedded channel sandstone and adjacent flood plain argillites cause collapsing along bedding plane surfaces. Rider coals overlying thin crevasse-splay sequences in close proximity to the No. 4 seam, create one of the most serious roof conditions; complete collapse occurs along the rider coal contact with the underlying splay deposits. Differential compaction of mudrock/shale/siltstone over more competent sandstone causes slickensided surfaces that weaken the roof lithologies. Correct identification of these sedimentological features will enable the prediction of potential poor roof conditions during mining operations and mine planning.
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A regional, 3-D computer-based sedimentological model of the permian Witbank coalfield, South Africa

- Grodner, Mark William

  • Authors: Grodner, Mark William
  • Date: 2009-01-28T09:41:56Z
  • Subjects: Geological modeling , Sedimentology , Computer simulation , Witbank (South Africa)
  • Type: Thesis
  • Identifier: uj:14839 , http://hdl.handle.net/10210/1962
  • Description: M.Sc. , The objective of this work is to establish a regional, three-dimensional sedimentological model of the clastic strata of the Vryheid Formation and pre-existing basin floor topography of the Witbank Coalfield, South Africa. This considers an area extending from 25°30’ S to 26°30’ S by 28°30’E to 30°E. This has been undertaken using computer modelling to examine the three-dimensional distribution of the sedimentary rocks. The basis for the geological model presented in this thesis is 1190 borehole logs collected from three mining companies involved in coal extraction in the study area, namely Anglo American Coal Corporation, Duiker Mining Limited and Ingwe Coal Corporation Limited. These borehole logs are converted to a common data format for inclusion into the 3-D model. These borehole logs are correctly positioned in space using a digital elevation model. The primary objective of this research was to visualize the interburden and overburden sedimentary rocks within the study area, so as to be able to understand the distribution and hence origin of these rocks. As commercially available modelling tools have several restrictions with respect to the current work, Geovision cc. was contracted to develop the tools needed for the geological visualization of the data. Using the three-dimensional model, the distribution of the various facies and facies associations can be defined, to understand the depositional history of the basin. These characteristics include the delineation of the general trend of the basement topography. The distribution of the lower glacial and paraglacial sedimentary rocks within the study in steep-sided palaeovalleys, marked by rapid facies and thickness changes from diamictite through argillite, and minor sandstones and conglomerates is shown in 3-D. Evidence of lobate deltas and bedload sandy river deposits between the No. 2 and No. 4 Seams is presented in 3-D. The 3-D characteristics of the rocks between the No. 4 and No. 5 Seams, proposed to represent a period of deltaic progradation during an overall marine transgression is described. By using a 3-D model it is possible to evaluate the distribution of sedimentary rocks, both through space and through time. These palaeoenvironmental interpretations facilitate a better understanding of the genesis of the Witbank Coalfield. Furthermore, this enhanced geological modelling can facilitate improved mine planning and mining techniques.
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Complexities of assessing palaeocave stratigraphy: reconstructing site formation of the ∼2.61 Ma Drimolen Makondo fossil site

- Murszewski, Ashleigh, Boschian, Giovanni, Herries, Andy I. R.

  • Authors: Murszewski, Ashleigh , Boschian, Giovanni , Herries, Andy I. R.
  • Date: 2020
  • Subjects: Micromorphology , Sedimentology , Pliocene
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/460076 , uj:40928 , Citation: Murszewski A, Boschian G, Herries AIR. 2020. Complexities of assessing palaeocave stratigraphy: reconstructing site formation of the ∼2.61 Ma Drimolen Makondo fossil site. PeerJ 8:e10360 http://doi.org/10.7717/peerj.10360
  • Description: Abstract: Palaeocave sites in South Africa are world renowned repositories for palaeontological and archaeological material, dating from the terminal Pliocene to the Early Pleistocene. Due to their antiquity, complex karstification history and multifaceted infilling phases, palaeocave sites are notoriously difficult to contextualise. Further to this, 19th century lime-mining and diverse excavation and sampling techniques, have complicated stratigraphic interpretations of fossil-bearing deposits within the region. Locating and assessing newly discovered, minimally disturbed palaeocave sites allow for contextual information to be gathered with greater confidence and can aid in constructing a more robust understanding of the South African fossil record. Here, we use Drimolen Makondo; a minimally lime-mined ∼2.61 Ma palaeontological site, to apply a series of in-depth stratigraphic and micromorphological studies. Contextual data presented within this study, testifies to a relatively rapid infill with greater fluvial activity when compared to adjacent deposits at the younger ∼2.04–1.95 Ma Drimolen Main Quarry. The quantity of articulated macromammalian remains, high density of micromammalian remains and pollen identified, also highlights Drimolen Makondo as a key site for ongoing palaeoenvironmental studies at the Pliocene to Pleistocene transition in South Africa.
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