Geochemistry and mineralogy of selected Atlantic Ocean basalts
Bibliography: p. 238-268. Bulk rock compositional variations in lavas from four localities in the Atlantic Ocean are evaluated quantitatively in terms of fractional crystallisation and partial melting models. Samples studied are from the Mid-Atlantic Ridge at 36°49 'N (FAMOUS), from the Islas O...
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1980
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ftunivcapetownir:oai:localhost:11427/18279 2023-05-15T13:42:14+02:00 Geochemistry and mineralogy of selected Atlantic Ocean basalts Le Roex, Anton Powter Erlank, A J Reid, A M 1980 application/pdf http://hdl.handle.net/11427/18279 https://open.uct.ac.za/bitstream/11427/18279/1/thesis_sci_1980_le_roex_anton_powter.pdf eng eng University of Cape Town Faculty of Science Department of Geological Sciences http://hdl.handle.net/11427/18279 https://open.uct.ac.za/bitstream/11427/18279/1/thesis_sci_1980_le_roex_anton_powter.pdf Geochemistry Doctoral Thesis Doctoral PhD 1980 ftunivcapetownir 2022-09-13T05:47:28Z Bibliography: p. 238-268. Bulk rock compositional variations in lavas from four localities in the Atlantic Ocean are evaluated quantitatively in terms of fractional crystallisation and partial melting models. Samples studied are from the Mid-Atlantic Ridge at 36°49 'N (FAMOUS), from the Islas Orcadas fracture zone on the Southwest Indian Ocean Ridge, from the Conrad fracture zone on the America-Antarctica Ridge and from Bouvet Island, situated at the southernmost tip of the Mid- Atlantic Ridge and in the vicinity of both the fracture zones mentioned above. Bulk rock major and trace element variations in selected basalts from the FAMOUS area, in conjunction with a detailed study of the chemistry of phenocryst minerals and associated melt inclusions are used to place constraints on the genetic relationships between the various lava types. The distribution of NiO in olivine and Cr-spinel phenocrysts distinguishes the picritic basalts, plagioclase phyric basalts and plagioclase-pyroxene basalts from the olivine basalts. The NiO content of these phenocrysts in the former three basalt types is low, or a given Mg Mg+Fe²⁺ atomic ratio of the mineral, relative to the phenocrysts in the olivine basalts. Consideration of the Zr/Nb ratio of the lavas similarly distinguishes the olivine basalts from the plagioclase phyric and plagioclase- pyroxene basalts but, in addition, distinguishes the picritic basalts from the former three basalt types. Doctoral or Postdoctoral Thesis Antarc* Antarctica Bouvet Island University of Cape Town: OpenUCT America-Antarctica Ridge ENVELOPE(-16.000,-16.000,-59.000,-59.000) Bouvet ENVELOPE(3.358,3.358,-54.422,-54.422) Bouvet Island ENVELOPE(3.358,3.358,-54.422,-54.422) Conrad Fracture Zone ENVELOPE(-4.000,-4.000,-56.000,-56.000) Indian Islas Orcadas Fracture Zone ENVELOPE(6.000,6.000,-54.283,-54.283) Mid-Atlantic Ridge Orcadas ENVELOPE(-44.717,-44.717,-60.750,-60.750) |
institution |
Open Polar |
collection |
University of Cape Town: OpenUCT |
op_collection_id |
ftunivcapetownir |
language |
English |
topic |
Geochemistry |
spellingShingle |
Geochemistry Le Roex, Anton Powter Geochemistry and mineralogy of selected Atlantic Ocean basalts |
topic_facet |
Geochemistry |
description |
Bibliography: p. 238-268. Bulk rock compositional variations in lavas from four localities in the Atlantic Ocean are evaluated quantitatively in terms of fractional crystallisation and partial melting models. Samples studied are from the Mid-Atlantic Ridge at 36°49 'N (FAMOUS), from the Islas Orcadas fracture zone on the Southwest Indian Ocean Ridge, from the Conrad fracture zone on the America-Antarctica Ridge and from Bouvet Island, situated at the southernmost tip of the Mid- Atlantic Ridge and in the vicinity of both the fracture zones mentioned above. Bulk rock major and trace element variations in selected basalts from the FAMOUS area, in conjunction with a detailed study of the chemistry of phenocryst minerals and associated melt inclusions are used to place constraints on the genetic relationships between the various lava types. The distribution of NiO in olivine and Cr-spinel phenocrysts distinguishes the picritic basalts, plagioclase phyric basalts and plagioclase-pyroxene basalts from the olivine basalts. The NiO content of these phenocrysts in the former three basalt types is low, or a given Mg Mg+Fe²⁺ atomic ratio of the mineral, relative to the phenocrysts in the olivine basalts. Consideration of the Zr/Nb ratio of the lavas similarly distinguishes the olivine basalts from the plagioclase phyric and plagioclase- pyroxene basalts but, in addition, distinguishes the picritic basalts from the former three basalt types. |
author2 |
Erlank, A J Reid, A M |
format |
Doctoral or Postdoctoral Thesis |
author |
Le Roex, Anton Powter |
author_facet |
Le Roex, Anton Powter |
author_sort |
Le Roex, Anton Powter |
title |
Geochemistry and mineralogy of selected Atlantic Ocean basalts |
title_short |
Geochemistry and mineralogy of selected Atlantic Ocean basalts |
title_full |
Geochemistry and mineralogy of selected Atlantic Ocean basalts |
title_fullStr |
Geochemistry and mineralogy of selected Atlantic Ocean basalts |
title_full_unstemmed |
Geochemistry and mineralogy of selected Atlantic Ocean basalts |
title_sort |
geochemistry and mineralogy of selected atlantic ocean basalts |
publisher |
University of Cape Town |
publishDate |
1980 |
url |
http://hdl.handle.net/11427/18279 https://open.uct.ac.za/bitstream/11427/18279/1/thesis_sci_1980_le_roex_anton_powter.pdf |
long_lat |
ENVELOPE(-16.000,-16.000,-59.000,-59.000) ENVELOPE(3.358,3.358,-54.422,-54.422) ENVELOPE(3.358,3.358,-54.422,-54.422) ENVELOPE(-4.000,-4.000,-56.000,-56.000) ENVELOPE(6.000,6.000,-54.283,-54.283) ENVELOPE(-44.717,-44.717,-60.750,-60.750) |
geographic |
America-Antarctica Ridge Bouvet Bouvet Island Conrad Fracture Zone Indian Islas Orcadas Fracture Zone Mid-Atlantic Ridge Orcadas |
geographic_facet |
America-Antarctica Ridge Bouvet Bouvet Island Conrad Fracture Zone Indian Islas Orcadas Fracture Zone Mid-Atlantic Ridge Orcadas |
genre |
Antarc* Antarctica Bouvet Island |
genre_facet |
Antarc* Antarctica Bouvet Island |
op_relation |
http://hdl.handle.net/11427/18279 https://open.uct.ac.za/bitstream/11427/18279/1/thesis_sci_1980_le_roex_anton_powter.pdf |
_version_ |
1766165619686768640 |