Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
The occurrences of ultramafic pegmatites at Dwarsrivier Mine, Lower Critical Zone, Eastern Bushveld Complex, South Africa
Dissertation (MSc)--University of Pretoria, 2017.
Saved in:
| Other Authors: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
University of Pretoria
2017
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613682487263232 |
|---|---|
| access_status_str | Open Access |
| author2 | Merkle, R.K.W. (Roland Karl Willi), 1954- |
| author_browse | Merkle, R.K.W. (Roland Karl Willi), 1954- |
| author_facet | Merkle, R.K.W. (Roland Karl Willi), 1954- |
| collection | Thesis |
| dc_rights_str_mv | © 2017 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc)--University of Pretoria, 2017. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/63298 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:40:01.664Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/63298 The occurrences of ultramafic pegmatites at Dwarsrivier Mine, Lower Critical Zone, Eastern Bushveld Complex, South Africa Merkle, R.K.W. (Roland Karl Willi), 1954- chrissbu2000@yahoo.com Letsoele, Christopher Sbusiso UCTD Ultramafic pegmatites Dwarsrivier Mine Lower Critical Zone Layered mafic intrusion Igneous petrology Chromitite layers Natural and agricultural sciences theses SDG-09 Natural and agricultural sciences theses SDG-12 Natural and agricultural sciences theses SDG-13 Dissertation (MSc)--University of Pretoria, 2017. This study presents a detailed petrological and geochemical investigation of the concordant ultramafic pegmatites of the Lower Critical Zone at Dwarsrivier Mine, in the eastern Bushveld Complex. The pegmatites are coarse-grained and of variable size and mineralogy. They occur within the LG-6 chromitite layer as well as in the silicate rocks of the Rustenburg Layered Suite. Field observations into their occurrence, and their association with the LG-6 chromitite layer, suggest that the pegmatites intrude, deform and disrupt the LG-6 chromitite. The mineralogy of the pegmatites is similar as the surrounding pyroxenite rocks, although they are texturally different from the surrounding pyroxenite host rocks. They comprise variable amounts of clinopyroxene, orthopyroxene, olivine, plagioclase, biotite and accessory amphiboles. Based on dominant mineralogy, the pegmatites can be grouped into clinopyroxene-, orthopyroxene- and olivine-rich pegmatites. The major and trace element composition of the pegmatites is different from the surrounding pyroxenite host rocks. The whole rock geochemistry of the pegmatites indicate that the pegmatites have a slightly higher concentration of incompatible trace elements compared to the pyroxenite host rocks, although compositional overlaps exist. Whole rock Mg# and trace element ratios suggests that the pegmatites are the products of less fractionated liquid(s) than their surrounding pyroxenite rocks. When the whole rock geochemical data of the pegmatites are compared to other similar concordant pegmatites in the eastern Bushveld Complex, as well as the discordant pegmatites from the western Bushveld Complex, it is established that the pegmatites at Dwarsrivier mine are not genetically related to the discordant, intrusive iron-rich pegmatites. They are also different from the concordant pegmatites found elsewhere in the eastern Bushveld Complex. The pegmatites are interpreted as the products of a volatile-rich melt which promoted the recrystallization or sub-solidus enlargement of the pyroxenes. The occurrence of cumulus olivine at the stratigraphic position of the Lower Critical Zone is exceptional. Olivine crystalized as a result of continuous phase shifts within the pegmatite melt. Some of the pegmatites are serpentinised by late hydrothermal fluids. The olivine-rich pegmatites display the most prominent serpentinisation, and are composed of a mineral assemblage dominated by serpentine and magnetite. Assmang Dwarsrivier Mine bs2026 Geology MSc Unrestricted SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production SDG-13: Climate action 2017-11-23T07:00:05Z 2017-11-23T07:00:05Z 2017 2017 Dissertation Letsoele, CS 2017, The occurrences of ultramafic pegmatites at Dwarsrivier Mine, Lower Critical Zone, Eastern Bushveld Complex, South Africa, MSc Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/63298> S2017 http://hdl.handle.net/2263/63298 en © 2017 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Ultramafic pegmatites Dwarsrivier Mine Lower Critical Zone Layered mafic intrusion Igneous petrology Chromitite layers Natural and agricultural sciences theses SDG-09 Natural and agricultural sciences theses SDG-12 Natural and agricultural sciences theses SDG-13 The occurrences of ultramafic pegmatites at Dwarsrivier Mine, Lower Critical Zone, Eastern Bushveld Complex, South Africa |
| title | The occurrences of ultramafic pegmatites at Dwarsrivier Mine, Lower Critical Zone, Eastern Bushveld Complex, South Africa |
| title_full | The occurrences of ultramafic pegmatites at Dwarsrivier Mine, Lower Critical Zone, Eastern Bushveld Complex, South Africa |
| title_fullStr | The occurrences of ultramafic pegmatites at Dwarsrivier Mine, Lower Critical Zone, Eastern Bushveld Complex, South Africa |
| title_full_unstemmed | The occurrences of ultramafic pegmatites at Dwarsrivier Mine, Lower Critical Zone, Eastern Bushveld Complex, South Africa |
| title_short | The occurrences of ultramafic pegmatites at Dwarsrivier Mine, Lower Critical Zone, Eastern Bushveld Complex, South Africa |
| title_sort | occurrences of ultramafic pegmatites at dwarsrivier mine lower critical zone eastern bushveld complex south africa |
| topic | UCTD Ultramafic pegmatites Dwarsrivier Mine Lower Critical Zone Layered mafic intrusion Igneous petrology Chromitite layers Natural and agricultural sciences theses SDG-09 Natural and agricultural sciences theses SDG-12 Natural and agricultural sciences theses SDG-13 |
| url | http://hdl.handle.net/2263/63298 |