Stable isotope geochemistry of the Okenyenya igneous complex, Namibia : constraints on contamination and fluid interaction

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dc.contributor.authorMartinez, Iúma Aparecidaen_ZA
dc.date.accessioned2016-09-06T14:44:02Z
dc.date.available2016-09-06T14:44:02Z
dc.date.issued1995en_ZA
dc.description.abstractThe δ¹⁸O values of coexisting silicate minerals in rocks comprising the tholeiitic olivine gabbro - quartz monzodiorite suite, are consistent with the attainment of isotope equilibrium and largely closed system conditions. The majority of the temperatures calculated by conventional mineral-pair thermometers are spurious, as a result of oxygen isotope diffusion during slow cooling. Closure temperatures for oxygen diffusion of 560ᵒC and 540ᵒC have been calculated for the anorthite-clinopyroxene and plagioclase-biotite mineral-pairs in the tholeiitic leucogabbro sample, respectively. The oxygen isotope data for the silicate minerals are consistent with contamination of the magmas by material having the oxygen isotope composition of the southern Etendeka rhyolite (δ¹⁸O = + 11.5‰). It is suggested that the assimilant may have been derived from the same source as the southern Etendeka rhyolite, as opposed to the rhyolite itself, which would be expected to occur at a high crustal level. Simple oxygen and strontium isotope mass balance calculations are used to constrain the lower (14 % and 19.5 % respectively) and upper (57 % and 71.6 % respectively) limits of the maximum possible amount of a southern Etendeka rhyolite contaminant assimilated.en_ZA
dc.identifier.apacitationMartinez, I. A. (1995). <i>Stable isotope geochemistry of the Okenyenya igneous complex, Namibia : constraints on contamination and fluid interaction</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Geological Sciences. Retrieved from http://hdl.handle.net/11427/21694en_ZA
dc.identifier.chicagocitationMartinez, Iúma Aparecida. <i>"Stable isotope geochemistry of the Okenyenya igneous complex, Namibia : constraints on contamination and fluid interaction."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Geological Sciences, 1995. http://hdl.handle.net/11427/21694en_ZA
dc.identifier.citationMartinez, I. 1995. Stable isotope geochemistry of the Okenyenya igneous complex, Namibia : constraints on contamination and fluid interaction. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Martinez, Iúma Aparecida AB - The δ¹⁸O values of coexisting silicate minerals in rocks comprising the tholeiitic olivine gabbro - quartz monzodiorite suite, are consistent with the attainment of isotope equilibrium and largely closed system conditions. The majority of the temperatures calculated by conventional mineral-pair thermometers are spurious, as a result of oxygen isotope diffusion during slow cooling. Closure temperatures for oxygen diffusion of 560ᵒC and 540ᵒC have been calculated for the anorthite-clinopyroxene and plagioclase-biotite mineral-pairs in the tholeiitic leucogabbro sample, respectively. The oxygen isotope data for the silicate minerals are consistent with contamination of the magmas by material having the oxygen isotope composition of the southern Etendeka rhyolite (δ¹⁸O = + 11.5‰). It is suggested that the assimilant may have been derived from the same source as the southern Etendeka rhyolite, as opposed to the rhyolite itself, which would be expected to occur at a high crustal level. Simple oxygen and strontium isotope mass balance calculations are used to constrain the lower (14 % and 19.5 % respectively) and upper (57 % and 71.6 % respectively) limits of the maximum possible amount of a southern Etendeka rhyolite contaminant assimilated. DA - 1995 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1995 T1 - Stable isotope geochemistry of the Okenyenya igneous complex, Namibia : constraints on contamination and fluid interaction TI - Stable isotope geochemistry of the Okenyenya igneous complex, Namibia : constraints on contamination and fluid interaction UR - http://hdl.handle.net/11427/21694 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/21694
dc.identifier.vancouvercitationMartinez IA. Stable isotope geochemistry of the Okenyenya igneous complex, Namibia : constraints on contamination and fluid interaction. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Geological Sciences, 1995 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/21694en_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.otherGeological Sciencesen_ZA
dc.subject.otherGeochemistryen_ZA
dc.titleStable isotope geochemistry of the Okenyenya igneous complex, Namibia : constraints on contamination and fluid interactionen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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