2D reflection seismic surveys to delineate manganese mineralisation beneath the thick Kalahari and Karoo cover in the Griqualand West Basin, South Africa.
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| Title: | 2D reflection seismic surveys to delineate manganese mineralisation beneath the thick Kalahari and Karoo cover in the Griqualand West Basin, South Africa. |
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| Authors: | Sihoyiya, Mpofana1 (AUTHOR) mpofana.sihoyiya@wits.ac.za, Manzi, Musa Siphiwe Doctor1 (AUTHOR), James, Ian1 (AUTHOR), Westgate, Michael1 (AUTHOR) |
| Source: | Solid Earth. 2026, Vol. 17 Issue 1, p135-154. 20p. |
| Subjects: | Seismic reflection method, Manganese ores, Sedimentary basins, Prospecting, Imaging systems in seismology |
| Geographic Terms: | South Africa, Northern Cape (South Africa) |
| Abstract: | The Kalahari Manganese Field (KMF) in the Northern Cape Province of South Africa hosts some of the world's richest manganese deposits, largely concealed beneath thick Cretaceous to Cenozoic Kalahari Group and Karoo Supergroup sediments. To improve imaging of the concealed Transvaal Supergroup strata, a high-resolution 2D reflection seismic survey was conducted in November 2023 across the Severn farm area. The survey comprised five profiles totalling 18.9 km , acquired using 5 Hz 1C geophones connected to wireless nodes, enabling effective burial beneath loose aeolian sand for improved coupling. A compact 500 kg drop hammer, mounted on a Bobcat, served as the seismic source, offering excellent manoeuvrability across challenging sandy terrain. Shot spacing was 10 m , with four vertical stacks per shot to enhance signal-to-noise ratio. Refraction tomography using first-break travel times provided near-surface P-wave velocity models, revealing variable Kalahari sediment thicknesses ranging from 20 to 70 m and bedrock velocities of ∼ 5500 ms-1 associated with Karoo Supergroup strata. Despite the challenges posed by the thick sand cover, lithified calcrete horizons within the Kalahari sediments significantly aided seismic energy propagation. The data were processed using a conventional pre-stack imaging workflow. We tested both Kirchhoff pre-stack time migration (KPreSTM) and Kirchhoff pre-stack depth migration (KPreSDM) and compared the results. Both migration approaches revealed a high degree of similarity in reflector geometries and structural patterns, suggesting minimal lateral velocity variation across the study area. KPreSTM results were then used in the final seismic interpretation. Pre-stack time migrated sections exhibit nine laterally continuous high-amplitude reflectors between 0.05 and 3.42 km depth, corresponding to major stratigraphic boundaries from the Kalahari Group down to the Ghaap Group. Of particular interest is the moderate-amplitude reflection pair at 1.05–1.35 km depth, interpreted as the Hotazel Formation, the primary host for manganese mineralization. This study demonstrates that, when appropriately designed, reflection seismic imaging can be a powerful tool for delineating deep mineralized strata beneath thick sedimentary cover in arid environments. [ABSTRACT FROM AUTHOR] |
| Copyright of Solid Earth is the property of Copernicus Gesellschaft mbH and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 191633112 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: 2D reflection seismic surveys to delineate manganese mineralisation beneath the thick Kalahari and Karoo cover in the Griqualand West Basin, South Africa. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Sihoyiya%2C+Mpofana%22">Sihoyiya, Mpofana</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> mpofana.sihoyiya@wits.ac.za</i><br /><searchLink fieldCode="AR" term="%22Manzi%2C+Musa Siphiwe Doctor%22">Manzi, Musa Siphiwe Doctor</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22James%2C+Ian%22">James, Ian</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Westgate%2C+Michael%22">Westgate, Michael</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Solid+Earth%22">Solid Earth</searchLink>. 2026, Vol. 17 Issue 1, p135-154. 20p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Seismic+reflection+method%22">Seismic reflection method</searchLink><br /><searchLink fieldCode="DE" term="%22Manganese+ores%22">Manganese ores</searchLink><br /><searchLink fieldCode="DE" term="%22Sedimentary+basins%22">Sedimentary basins</searchLink><br /><searchLink fieldCode="DE" term="%22Prospecting%22">Prospecting</searchLink><br /><searchLink fieldCode="DE" term="%22Imaging+systems+in+seismology%22">Imaging systems in seismology</searchLink> – Name: SubjectGeographic Label: Geographic Terms Group: Su Data: <searchLink fieldCode="DE" term="%22South+Africa%22">South Africa</searchLink><br /><searchLink fieldCode="DE" term="%22Northern+Cape+%28South+Africa%29%22">Northern Cape (South Africa)</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The Kalahari Manganese Field (KMF) in the Northern Cape Province of South Africa hosts some of the world's richest manganese deposits, largely concealed beneath thick Cretaceous to Cenozoic Kalahari Group and Karoo Supergroup sediments. To improve imaging of the concealed Transvaal Supergroup strata, a high-resolution 2D reflection seismic survey was conducted in November 2023 across the Severn farm area. The survey comprised five profiles totalling 18.9 km , acquired using 5 Hz 1C geophones connected to wireless nodes, enabling effective burial beneath loose aeolian sand for improved coupling. A compact 500 kg drop hammer, mounted on a Bobcat, served as the seismic source, offering excellent manoeuvrability across challenging sandy terrain. Shot spacing was 10 m , with four vertical stacks per shot to enhance signal-to-noise ratio. Refraction tomography using first-break travel times provided near-surface P-wave velocity models, revealing variable Kalahari sediment thicknesses ranging from 20 to 70 m and bedrock velocities of ∼ 5500 ms-1 associated with Karoo Supergroup strata. Despite the challenges posed by the thick sand cover, lithified calcrete horizons within the Kalahari sediments significantly aided seismic energy propagation. The data were processed using a conventional pre-stack imaging workflow. We tested both Kirchhoff pre-stack time migration (KPreSTM) and Kirchhoff pre-stack depth migration (KPreSDM) and compared the results. Both migration approaches revealed a high degree of similarity in reflector geometries and structural patterns, suggesting minimal lateral velocity variation across the study area. KPreSTM results were then used in the final seismic interpretation. Pre-stack time migrated sections exhibit nine laterally continuous high-amplitude reflectors between 0.05 and 3.42 km depth, corresponding to major stratigraphic boundaries from the Kalahari Group down to the Ghaap Group. Of particular interest is the moderate-amplitude reflection pair at 1.05–1.35 km depth, interpreted as the Hotazel Formation, the primary host for manganese mineralization. This study demonstrates that, when appropriately designed, reflection seismic imaging can be a powerful tool for delineating deep mineralized strata beneath thick sedimentary cover in arid environments. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Solid Earth is the property of Copernicus Gesellschaft mbH and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
| PLink | https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=191633112 |
| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.5194/se-17-135-2026 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 20 StartPage: 135 Subjects: – SubjectFull: Seismic reflection method Type: general – SubjectFull: Manganese ores Type: general – SubjectFull: Sedimentary basins Type: general – SubjectFull: Prospecting Type: general – SubjectFull: Imaging systems in seismology Type: general – SubjectFull: South Africa Type: general – SubjectFull: Northern Cape (South Africa) Type: general Titles: – TitleFull: 2D reflection seismic surveys to delineate manganese mineralisation beneath the thick Kalahari and Karoo cover in the Griqualand West Basin, South Africa. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Sihoyiya, Mpofana – PersonEntity: Name: NameFull: Manzi, Musa Siphiwe Doctor – PersonEntity: Name: NameFull: James, Ian – PersonEntity: Name: NameFull: Westgate, Michael IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 01 Text: 2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 18699510 Numbering: – Type: volume Value: 17 – Type: issue Value: 1 Titles: – TitleFull: Solid Earth Type: main |
| ResultId | 1 |
