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Determining the physico-chemical conditions on the early earth : Barberton scientific drilling project, South Africa
Includes bibliographical references (leaves 146-162).
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| Main Author: | |
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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Department of Geological Sciences
2014
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| _version_ | 1867613151183241216 |
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| access_status_str | Open Access |
| author | Grosch, Eugene Gerald |
| author2 | Richardson, Steve |
| author_browse | Grosch, Eugene Gerald Richardson, Steve |
| author_facet | Richardson, Steve Grosch, Eugene Gerald |
| author_sort | Grosch, Eugene Gerald |
| collection | Thesis |
| description | Includes bibliographical references (leaves 146-162). |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/9239 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:31:34.243Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2014 |
| publishDateRange | 2014 |
| publishDateSort | 2014 |
| publisher | Department of Geological Sciences |
| publisherStr | Department of Geological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/9239 Determining the physico-chemical conditions on the early earth : Barberton scientific drilling project, South Africa Grosch, Eugene Gerald Richardson, Steve Geological Sciences Includes bibliographical references (leaves 146-162). Low-grade metabasites and hydrothermally altered ultramafic rocks comprise most of the ca. 3.5-3.2 Ga, Paleoarchean Barberton Greenstone Belt (BGB) of South Africa. However, PT-constraints and detailed petrological information on the variably altered mafic-ultramafic rocks are sparse and the nature of greenschist facies metamorphism is poorly characterized. In addition, alteration and silicification associated with distinct emerald green, fuchsite-(Crmica)- carbonate-quartz alteration zones is commonly found beneath chert horizons in the mafic-ultramafic rocks of the Onverwacht Group of the BGB. The origin of this silicification is highly debated and has important bearing on the nature of Paleoarchean geodynamic models, crustal geothermal gradients, hydrothermal oceanic regimes, as well as potential early life-sustaining environments. Over the past four decades, widely varying interpretations have been reported for the origin of these silica-rich fuchsitic alteration zones in the BGB, ranging from very low temperature (less than 60oC) atmospheric weathering of komatiites (Lowe and Byerly, 1986; 1999); low-temperature (less than 125oC) seafloor alteration (Hofmann and Harris, 2008); to bedding-parallel ‘flaser-banded gneissesschists’ in oceanic ‘extensionaloverthrust glide planes’ (de Wit, 1982a; 1986a,b; de Wit et al., 1982b; 1987b; 2011). Consequently, these fuchsitic-alteration zones have been at the centre of much debate surrounding stratigraphy models and the possible operation of early Paleoarchean platetectonic processes in the BGB. 2014-11-05T17:30:47Z 2014-11-05T17:30:47Z 2011 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/9239 eng application/pdf Department of Geological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Geological Sciences Grosch, Eugene Gerald Determining the physico-chemical conditions on the early earth : Barberton scientific drilling project, South Africa |
| thesis_degree_str | Doctoral |
| title | Determining the physico-chemical conditions on the early earth : Barberton scientific drilling project, South Africa |
| title_full | Determining the physico-chemical conditions on the early earth : Barberton scientific drilling project, South Africa |
| title_fullStr | Determining the physico-chemical conditions on the early earth : Barberton scientific drilling project, South Africa |
| title_full_unstemmed | Determining the physico-chemical conditions on the early earth : Barberton scientific drilling project, South Africa |
| title_short | Determining the physico-chemical conditions on the early earth : Barberton scientific drilling project, South Africa |
| title_sort | determining the physico chemical conditions on the early earth barberton scientific drilling project south africa |
| topic | Geological Sciences |
| url | http://hdl.handle.net/11427/9239 |
| work_keys_str_mv | AT groscheugenegerald determiningthephysicochemicalconditionsontheearlyearthbarbertonscientificdrillingprojectsouthafrica |