Structural and metamorphic evolution of a gneiss terrain in the Namaqua Belt near Onseepkans, South West Africa

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dc.contributor.advisorKroner, Aen_ZA
dc.contributor.authorToogood, David Jen_ZA
dc.date.accessioned2016-10-27T14:24:31Z
dc.date.available2016-10-27T14:24:31Z
dc.date.issued1976en_ZA
dc.descriptionBibliography: p. 173-189.en_ZA
dc.description.abstractA 4000 km² area of Precambrian rocks in the Namaqua belt has been examined and it is concluded the present structural and metamorphic framework is the result of a complex polydeformational and polymetamorphic evolution. A major crustal break is present in the area and is represented by a northwest trending dextral shear zone - the Pofadder ZAHNCAFS. The zone of reorientation associated with this shear zone controls the geometry of the western part of the area. The shear zone varies in width from 20 to 40 km and the core contains a 2 km - 7 km wide belt of mylonites. Two sets of folds (D₅ and D₆) have been formed in the zone of reorientation in the northern block. The D₅ folds are northeast trending en-echelon structures up to 30 km long and the interference pattern produced by superimposed northwest trending D₆ folds has resulted in a series of crescent-shaped antiforms. These folds are not present in the southern block and this is thought to be due to a pressure shadow effect connected with the nearby Vioolsdrif complex. Components of both pure shear and simple shear were involved in the shear zone development and a minimum displacement of 85 km is indicated by the strain analysis. The shear zone developed under medium to high-grade metamorphic conditions and the mylonites were formed by a process of dislocation and recovery.en_ZA
dc.identifier.apacitationToogood, D. J. (1976). <i>Structural and metamorphic evolution of a gneiss terrain in the Namaqua Belt near Onseepkans, South West Africa</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Geological Sciences. Retrieved from http://hdl.handle.net/11427/22331en_ZA
dc.identifier.chicagocitationToogood, David J. <i>"Structural and metamorphic evolution of a gneiss terrain in the Namaqua Belt near Onseepkans, South West Africa."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Geological Sciences, 1976. http://hdl.handle.net/11427/22331en_ZA
dc.identifier.citationToogood, D. 1976. Structural and metamorphic evolution of a gneiss terrain in the Namaqua Belt near Onseepkans, South West Africa. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Toogood, David J AB - A 4000 km² area of Precambrian rocks in the Namaqua belt has been examined and it is concluded the present structural and metamorphic framework is the result of a complex polydeformational and polymetamorphic evolution. A major crustal break is present in the area and is represented by a northwest trending dextral shear zone - the Pofadder ZAHNCAFS. The zone of reorientation associated with this shear zone controls the geometry of the western part of the area. The shear zone varies in width from 20 to 40 km and the core contains a 2 km - 7 km wide belt of mylonites. Two sets of folds (D₅ and D₆) have been formed in the zone of reorientation in the northern block. The D₅ folds are northeast trending en-echelon structures up to 30 km long and the interference pattern produced by superimposed northwest trending D₆ folds has resulted in a series of crescent-shaped antiforms. These folds are not present in the southern block and this is thought to be due to a pressure shadow effect connected with the nearby Vioolsdrif complex. Components of both pure shear and simple shear were involved in the shear zone development and a minimum displacement of 85 km is indicated by the strain analysis. The shear zone developed under medium to high-grade metamorphic conditions and the mylonites were formed by a process of dislocation and recovery. DA - 1976 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1976 T1 - Structural and metamorphic evolution of a gneiss terrain in the Namaqua Belt near Onseepkans, South West Africa TI - Structural and metamorphic evolution of a gneiss terrain in the Namaqua Belt near Onseepkans, South West Africa UR - http://hdl.handle.net/11427/22331 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/22331
dc.identifier.vancouvercitationToogood DJ. Structural and metamorphic evolution of a gneiss terrain in the Namaqua Belt near Onseepkans, South West Africa. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Geological Sciences, 1976 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/22331en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Geological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherGeologyen_ZA
dc.titleStructural and metamorphic evolution of a gneiss terrain in the Namaqua Belt near Onseepkans, South West Africaen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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