Post-Impact Faulting of the Holfontein Granophyre Dike of the Vredefort Impact Structure, South Africa, Inferred from Remote Sensing, Geophysics, and Geochemistry
| dc.contributor.author | Clark, Martin D | |
| dc.contributor.author | Kovaleva, Elizaveta | |
| dc.contributor.author | Huber, Matthew S | |
| dc.contributor.author | Fourie, Francois | |
| dc.contributor.author | Harris, Chris | |
| dc.date.accessioned | 2021-10-19T11:25:49Z | |
| dc.date.available | 2021-10-19T11:25:49Z | |
| dc.date.issued | 2021-02-19 | |
| dc.date.updated | 2021-02-26T14:42:29Z | |
| dc.description.abstract | Better characterization features borne from long-term crustal modification processes is essential for understanding the dynamics of large basin-forming impact structures on Earth. Within the deeply eroded 2.02 Ga Vredefort Impact Structure in South Africa, impact melt dikes are exposed at the surface. In this study, we utilized a combination of field, remote sensing, electrical resistivity, magnetic, petrographical, and geochemical techniques to characterize one such impact melt dike, namely, the Holfontein Granophyre Dike (HGD), along with the host granites. The HGD is split into two seemingly disconnected segments. Geophysical modeling of both segments suggests that the melt rock does not penetrate below the modern surface deeper than 5 m, which was confirmed by a later transecting construction trench. Even though the textures and clast content are different in two segments, the major element, trace element, and O isotope compositions of each segment are indistinguishable. Structural measurements of the tectonic foliations in the granites, as well as the spatial expression of the dike, suggest that the dike was segmented by an ENE–WSW trending sinistral strike-slip fault zone. Such an offset must have occurred after the dike solidified. However, the Vredefort structure has not been affected by any major tectonic events after the impact occurred. Therefore, the inferred segmentation of the HGD is consistent with long-term crustal processes occurring in the post-impact environment. These crustal processes may have involved progressive uplift of the crater floor, which is consistent with post-impact long-term crustal adjustment that has been inferred for craters on the Moon. | en_US |
| dc.identifier | doi: 10.3390/geosciences11020096 | |
| dc.identifier.apacitation | Clark, M. D., Kovaleva, E., Huber, M. S., Fourie, F., & Harris, C. (2021). Post-Impact Faulting of the Holfontein Granophyre Dike of the Vredefort Impact Structure, South Africa, Inferred from Remote Sensing, Geophysics, and Geochemistry. <i>Geosciences</i>, 11(2), http://hdl.handle.net/11427/35267 | en_ZA |
| dc.identifier.chicagocitation | Clark, Martin D, Elizaveta Kovaleva, Matthew S Huber, Francois Fourie, and Chris Harris "Post-Impact Faulting of the Holfontein Granophyre Dike of the Vredefort Impact Structure, South Africa, Inferred from Remote Sensing, Geophysics, and Geochemistry." <i>Geosciences</i> 11, 2. (2021) http://hdl.handle.net/11427/35267 | en_ZA |
| dc.identifier.citation | Clark, M.D., Kovaleva, E., Huber, M.S., Fourie, F. & Harris, C. 2021. Post-Impact Faulting of the Holfontein Granophyre Dike of the Vredefort Impact Structure, South Africa, Inferred from Remote Sensing, Geophysics, and Geochemistry. <i>Geosciences.</i> 11(2) http://hdl.handle.net/11427/35267 | en_ZA |
| dc.identifier.ris | TY - Journal Article AU - Clark, Martin D AU - Kovaleva, Elizaveta AU - Huber, Matthew S AU - Fourie, Francois AU - Harris, Chris AB - Better characterization features borne from long-term crustal modification processes is essential for understanding the dynamics of large basin-forming impact structures on Earth. Within the deeply eroded 2.02 Ga Vredefort Impact Structure in South Africa, impact melt dikes are exposed at the surface. In this study, we utilized a combination of field, remote sensing, electrical resistivity, magnetic, petrographical, and geochemical techniques to characterize one such impact melt dike, namely, the Holfontein Granophyre Dike (HGD), along with the host granites. The HGD is split into two seemingly disconnected segments. Geophysical modeling of both segments suggests that the melt rock does not penetrate below the modern surface deeper than 5 m, which was confirmed by a later transecting construction trench. Even though the textures and clast content are different in two segments, the major element, trace element, and O isotope compositions of each segment are indistinguishable. Structural measurements of the tectonic foliations in the granites, as well as the spatial expression of the dike, suggest that the dike was segmented by an ENE–WSW trending sinistral strike-slip fault zone. Such an offset must have occurred after the dike solidified. However, the Vredefort structure has not been affected by any major tectonic events after the impact occurred. Therefore, the inferred segmentation of the HGD is consistent with long-term crustal processes occurring in the post-impact environment. These crustal processes may have involved progressive uplift of the crater floor, which is consistent with post-impact long-term crustal adjustment that has been inferred for craters on the Moon. DA - 2021-02-19 DB - OpenUCT DP - University of Cape Town IS - 2 J1 - Geosciences KW - deep crust KW - post-impact deformation KW - meteorite impact KW - Kaapvaal Craton LK - https://open.uct.ac.za PY - 2021 T1 - Post-Impact Faulting of the Holfontein Granophyre Dike of the Vredefort Impact Structure, South Africa, Inferred from Remote Sensing, Geophysics, and Geochemistry TI - Post-Impact Faulting of the Holfontein Granophyre Dike of the Vredefort Impact Structure, South Africa, Inferred from Remote Sensing, Geophysics, and Geochemistry UR - http://hdl.handle.net/11427/35267 ER - | en_ZA |
| dc.identifier.uri | https://doi.org/10.3390/geosciences11020096 | |
| dc.identifier.uri | http://hdl.handle.net/11427/35267 | |
| dc.identifier.vancouvercitation | Clark MD, Kovaleva E, Huber MS, Fourie F, Harris C. Post-Impact Faulting of the Holfontein Granophyre Dike of the Vredefort Impact Structure, South Africa, Inferred from Remote Sensing, Geophysics, and Geochemistry. Geosciences. 2021;11(2) http://hdl.handle.net/11427/35267. | en_ZA |
| dc.language.iso | en | en_US |
| dc.publisher.department | Department of Geological Sciences | en_US |
| dc.publisher.faculty | Faculty of Science | en_US |
| dc.rights.uri | http://creativecommons.org/licenses/by/4.0/ | en_US |
| dc.source | Geosciences | en_US |
| dc.source.journalissue | 2 | en_US |
| dc.source.journalvolume | 11 | en_US |
| dc.source.uri | https://www.mdpi.com/journal/geosciences | |
| dc.subject | deep crust | |
| dc.subject | post-impact deformation | |
| dc.subject | meteorite impact | |
| dc.subject | Kaapvaal Craton | |
| dc.title | Post-Impact Faulting of the Holfontein Granophyre Dike of the Vredefort Impact Structure, South Africa, Inferred from Remote Sensing, Geophysics, and Geochemistry | en_US |
| dc.type | Journal Article | en_US |