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The geology of the western Nuba Mountains region South Kordofan State Sudan with special emphasis on the low-grade Neoproterozoic meta-volcano-sedimentary sequence
Thesis (PhD)--University of Pretoria, 2017.
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University of Pretoria
2017
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| _version_ | 1867613550914043904 |
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| access_status_str | Open Access |
| author2 | Bumby, Adam John |
| author_browse | Bumby, Adam John |
| author_facet | Bumby, Adam John |
| 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 | Thesis (PhD)--University of Pretoria, 2017. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/63214 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:56.361Z |
| 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:2263/63214 The geology of the western Nuba Mountains region South Kordofan State Sudan with special emphasis on the low-grade Neoproterozoic meta-volcano-sedimentary sequence Bumby, Adam John ibnouf77@gmail.com Grantham, Geoff H. Ibinoof, Montasir Ahmed UCTD Regional geology Nuba Mountains Neoproterozoic Volcano-sedimentary rocks Low-grade metamorphism Natural and agricultural sciences theses SDG-09 Thesis (PhD)--University of Pretoria, 2017. Dismembered and low-grade metamorphosed occurrences of mafic extrusive and intrusive and minor ultramafic rocks, grouped as the Arid unit, similar to those of the Arabian Nubian Shield (ANS), are reported here for the first time in the westernmost part of the Nuba Mountains, southeastern Sudan. These occurrences are interpreted to represent part of an ophiolite sequence with a lower cumulate layer composed of layered gabbro and minor cumulate hornblendite and a top layer of thick massive gabbro, pillowed basalt and basaltic andesite. The Arid unit is structurally underlain by basaltic-andesite and andesite and a metasedimentary sequence identified as turbidite and both grouped as the Abutulu unit. All of the rocks are slightly sheared, deformed and metamorphosed under low-grade greenschist facies. New geochemical and Sr-Nd isotope data reveal that the low-grade metavolcanic rocks of the westernmost Nuba Mountains represent a Neoproterozoic oceanic arc/back-arc assemblage. The massive gabbro and pillowed basalt of the Arid unit show the geochemical characteristics of HFSE-depleted tholeiitic basalt while the co-genetic and more evolved meta-andesite of Abutulu unit show a calc-alkaline signature. Both units display a REE pattern characterized by LILE enrichment indicating formation in an arc/back-arc environment. This arc was active at around 778±90 Ma (Sm-Nd 12 WR isochron) that is similar in age to arc magmatism in the ANS. The close interval between the TDM Nd model age (average of 10 metavolcanic samples is 814 Ma) and the crystallization age (778±90 Ma) is indicative of little or no involvement of older crustal material. The western Nuba Mountains metavolcanic rocks have εNd values of +5.9 at 778 Ma (average of 12 samples) indicating a depleted mantle source similar to that of the ANS (published range from +6.5 to +8.4). The metavolcanic rocks are structurally bounded from the eastern side by mediumgrade orthogneisses and supracrustal metasediments intruded by syn to late-orogenic granite. Based on their geochemistry and isotopic characteristics these gneisses are interpreted to be evolved from an arc magma source of early Neoproterozoic age 976±58 Ma corresponds to εNd value of +6.3±0.9 (six point Nd isochron). The tight clustering of εNd values and the TDM Nd model ages preclude significant involvement of older crustal material and hence these gneisses are assigned to intra-oceanic arc environments. bs2026 Geology PhD Unrestricted SDG-09: Industry, innovation and infrastructure 2017-11-20T10:10:53Z 2017-11-20T10:10:53Z 2017 2017 Dissertation Ibinoof, MA 2017, The geology of the western Nuba Mountains region South Kordofan State Sudan with special emphasis on the low-grade Neoproterozoic meta-volcano-sedimentary sequence, PhD Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/63214> S2017 http://hdl.handle.net/2263/63214 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 Regional geology Nuba Mountains Neoproterozoic Volcano-sedimentary rocks Low-grade metamorphism Natural and agricultural sciences theses SDG-09 The geology of the western Nuba Mountains region South Kordofan State Sudan with special emphasis on the low-grade Neoproterozoic meta-volcano-sedimentary sequence |
| title | The geology of the western Nuba Mountains region South Kordofan State Sudan with special emphasis on the low-grade Neoproterozoic meta-volcano-sedimentary sequence |
| title_full | The geology of the western Nuba Mountains region South Kordofan State Sudan with special emphasis on the low-grade Neoproterozoic meta-volcano-sedimentary sequence |
| title_fullStr | The geology of the western Nuba Mountains region South Kordofan State Sudan with special emphasis on the low-grade Neoproterozoic meta-volcano-sedimentary sequence |
| title_full_unstemmed | The geology of the western Nuba Mountains region South Kordofan State Sudan with special emphasis on the low-grade Neoproterozoic meta-volcano-sedimentary sequence |
| title_short | The geology of the western Nuba Mountains region South Kordofan State Sudan with special emphasis on the low-grade Neoproterozoic meta-volcano-sedimentary sequence |
| title_sort | geology of the western nuba mountains region south kordofan state sudan with special emphasis on the low grade neoproterozoic meta volcano sedimentary sequence |
| topic | UCTD Regional geology Nuba Mountains Neoproterozoic Volcano-sedimentary rocks Low-grade metamorphism Natural and agricultural sciences theses SDG-09 |
| url | http://hdl.handle.net/2263/63214 |