- Title
- Sedimentology, petrography and geochemistry of the Kuruman Banded Iron Formation in the Prieska area, Northern Cape Province of South Africa
- Creator
- Mbongonya, Mainly Abongile https://orcid.org/0000-0003-2241-8558
- Subject
- Mines and mineral resources -- South Africa
- Subject
- Sedimentology
- Date
- 2021-01
- Type
- Master's theses
- Type
- text
- Identifier
- http://hdl.handle.net/10353/21345
- Identifier
- vital:48492
- Description
- The sedimentary sequences hosted by the Griqualand West Basin within the Transvaal Supergroup, Northern Cape Province of South Africa, contain several iron and manganese ore deposits. Many studies have been conducted in the Griqualand West basin, particularly within the northern Ghaap plateau compartment where most iron and manganese mines are located, with less attention to the southern Prieska Compartment. Thus, the current study is targeted at the Kuruman Formation in the Prieska area to investigate the geological occurrence, including sedimentology, geochemistry, origin, and post-depositional alteration of the banded iron formation (BIF). Four stratigraphic sections were measured, and the fifth section was only mapped for lithology and sedimentary facies. These sections constitute portions of the stratigraphic sequence of the Transvaal Supergroup that occurs within the study area. The stratigraphic sequence of the area comprises nine successional cycles with five upward fining cycles and four upward-coarsening cycles. These cycles reflect fluctuation of the sea level and shallowing- and filling-up processes of the final basin. Four mineral paragenetic groups constituting primary minerals, diagenetic minerals, low-grade minerals, and weathering mineral assemblages were encountered in the area. The primary mineral assemblage includes magnetite, hematite, siderite, chert, quartz, and smectite. The diagenetic assemblage minerals in the area are martite, quartz (cement), illite, calcite, ankerite, and stilpnomelane. Low-grade assemblage minerals are riebeckite, crocidolite, and minnesotaite, whereas goethite, limonite, calcite (calcrete), quartz (silcrete), and clay minerals are the supergene (weathering) assemblage minerals. These mineral assemblages were confirmed by microscope petrography, XRD, SEM-EDX, and diagenesis studies. Eight sedimentary facies including Horizontal-laminated BIF facies (Hlb), Horizontal thin to medium bedded BIF facies (Hbb), Ripple laminated BIF facies (Rlb), Thin to medium bedded mudstone facies (Mbm), Medium to thick-bedded mudstone facies (Tbm), Medium to thick-bedded fine-sandstone facies (Mts), Laminated dolomite stromatolite facies (Ld), and Dome-shaped stromatolitic BIF facies (Dbif) were identified in the field. Five facies associations including Facies association 1 (Hlb + Hbb), Facies association 2 (Hlb + Hbb + Mbm + Tbm), Facies association 3 (Hlb + Hbb + Mbm + Tbm + Rlb), Facies association 4 (Mbm + Tbm + Mts), and Facies association 5 (Ld + Dbif + Mts) have been recognised. Mineralogy, petrography, and geochemical studies indicate that the studied samples have all been subjected to recent weathering that altered the primary mineralogy and the geochemical composition. Mineral assemblages of the Kuruman BIF within the Prieska area are dominated by quartz, which constitutes about 53 wt.percent, followed by the iron oxides averaging about 44 wt.percent. Other minerals such as carbonates and silicates are only occurring in concentrations of less than 3 wt. percent combined. The Prieska BIF is enriched in cobalt, tungsten, molybdenum, barium (Ba), and nickel compared to the BIF in the northern parts of the Griqualand West basin and other localities. Post-depositional mineral alteration studies show that most of the primary minerals had suffered various degrees of alteration. The bulk of quartz, silicate, and iron oxide minerals in the area have been recrystallized, partially replaced, dissolved, or leached out. Multiple formation processes were involved in the origin of the banded iron formation: (1). Deposition of iron-rich mud material in the deep ocean floor and formation of a mixture of iron-rich mud (felutite) on the seafloor; (2). Differentiation of felutite and formation of disseminated iron-oxide from mud; (3). Cohesion and diagenesis of disseminated iron-oxide and formation of iron-rich (magnetite/hematite) and silica-rich (chert/quartz) patches, lenses (pod), microbands, and laminations; (4). Consolidation and compaction, leading to the formation of the final banded iron formation (BIF).
- Description
- Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (187 leaves)
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
- Rights
- All Rights Reserved
- Rights
- Open Access
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UFH Department of Geology
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details | SOURCE1 | Mbongonya (200505372) _MSc Dissertation.pdf | 16 MB | Adobe Acrobat PDF | View Details |