Plume-lithosphere interaction : geochemical evidence from upper mantle and lower crustal xenoliths from the Kerguelen Islands
Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences; and the Woods Hole Oceanographic Institution), 1999. Includes bibliographical references. This study is a geochemical investigation of the evolution of the Kergu...
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ftmit:oai:dspace.mit.edu:1721.1/54434 2023-06-11T04:12:27+02:00 Plume-lithosphere interaction : geochemical evidence from upper mantle and lower crustal xenoliths from the Kerguelen Islands Hassler, Deborah Renee, 1961- Nobumichi Shimizu. Joint Program in Oceanography. Joint Program in Oceanography Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Woods Hole Oceanographic Institution 1999 368 leaves application/pdf http://hdl.handle.net/1721.1/54434 eng eng Massachusetts Institute of Technology http://hdl.handle.net/1721.1/54434 43855982 M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Joint Program in Oceanography Massachusetts Institute of Technology. Dept. of Earth Atmospheric and Planetary Sciences Woods Hole Oceanographic Institution Thesis 1999 ftmit 2023-05-29T07:26:54Z Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences; and the Woods Hole Oceanographic Institution), 1999. Includes bibliographical references. This study is a geochemical investigation of the evolution of the Kerguelen plume, on the basis of upper mantle and lower crustal xenoliths. Ultramafic xenoliths include harzburgites predominant, a lherzolite, dunites and pyroxenites, whereas lower crustal xenoliths are cumulate gabbros recrystallized under granulite facies conditions. On the basis of the whole rock major element characteristics and trace element abundance patterns in clinopyroxenes, the harzburgites were found to be residues of extensive melting at high pressures within the Kerguelen plume. These were then recrystallized at low pressures and metasomatized by plume generated melts. Details of the metasomatic process were determined from trace element variations in clinopyroxene in connection to texture. This demonstrated that meltrock reaction and the precipitation of new clinopyroxenes occurred by metasomatic carbonatitic melts. It was also found that some of the harzburgites had distinctly unradiogenic Os isotopic compositions and were identified as originating from the sub-Gondwanaland lithosphere. On the basis of major and trace element compositions, the granulite xenoliths were found to be originally gabbroic cumulates formed from plume-derived basaltic melts emplaced at the base of the crust by underplating and subsequently recrystallized isobarically under granulite conditions. The Sr, Nd and Os isotopic compositions of the peridotite and granulite xenoliths demonstrate that the Kerguelen plume is isotopically heterogeneous and displays a temporal progression toward more enriched Sr and Nd isotopic compositions from the Ninetyeast Ridge to granulite xenoliths to Kerguelen basalts and Heard Island basalts. by Deborah Renee Hassler. Ph.D. Thesis Heard Island Kerguelen Islands DSpace@MIT (Massachusetts Institute of Technology) Kerguelen Heard Island Kerguelen Islands |
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DSpace@MIT (Massachusetts Institute of Technology) |
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ftmit |
language |
English |
topic |
Joint Program in Oceanography Massachusetts Institute of Technology. Dept. of Earth Atmospheric and Planetary Sciences Woods Hole Oceanographic Institution |
spellingShingle |
Joint Program in Oceanography Massachusetts Institute of Technology. Dept. of Earth Atmospheric and Planetary Sciences Woods Hole Oceanographic Institution Hassler, Deborah Renee, 1961- Plume-lithosphere interaction : geochemical evidence from upper mantle and lower crustal xenoliths from the Kerguelen Islands |
topic_facet |
Joint Program in Oceanography Massachusetts Institute of Technology. Dept. of Earth Atmospheric and Planetary Sciences Woods Hole Oceanographic Institution |
description |
Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences; and the Woods Hole Oceanographic Institution), 1999. Includes bibliographical references. This study is a geochemical investigation of the evolution of the Kerguelen plume, on the basis of upper mantle and lower crustal xenoliths. Ultramafic xenoliths include harzburgites predominant, a lherzolite, dunites and pyroxenites, whereas lower crustal xenoliths are cumulate gabbros recrystallized under granulite facies conditions. On the basis of the whole rock major element characteristics and trace element abundance patterns in clinopyroxenes, the harzburgites were found to be residues of extensive melting at high pressures within the Kerguelen plume. These were then recrystallized at low pressures and metasomatized by plume generated melts. Details of the metasomatic process were determined from trace element variations in clinopyroxene in connection to texture. This demonstrated that meltrock reaction and the precipitation of new clinopyroxenes occurred by metasomatic carbonatitic melts. It was also found that some of the harzburgites had distinctly unradiogenic Os isotopic compositions and were identified as originating from the sub-Gondwanaland lithosphere. On the basis of major and trace element compositions, the granulite xenoliths were found to be originally gabbroic cumulates formed from plume-derived basaltic melts emplaced at the base of the crust by underplating and subsequently recrystallized isobarically under granulite conditions. The Sr, Nd and Os isotopic compositions of the peridotite and granulite xenoliths demonstrate that the Kerguelen plume is isotopically heterogeneous and displays a temporal progression toward more enriched Sr and Nd isotopic compositions from the Ninetyeast Ridge to granulite xenoliths to Kerguelen basalts and Heard Island basalts. by Deborah Renee Hassler. Ph.D. |
author2 |
Nobumichi Shimizu. Joint Program in Oceanography. Joint Program in Oceanography Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Woods Hole Oceanographic Institution |
format |
Thesis |
author |
Hassler, Deborah Renee, 1961- |
author_facet |
Hassler, Deborah Renee, 1961- |
author_sort |
Hassler, Deborah Renee, 1961- |
title |
Plume-lithosphere interaction : geochemical evidence from upper mantle and lower crustal xenoliths from the Kerguelen Islands |
title_short |
Plume-lithosphere interaction : geochemical evidence from upper mantle and lower crustal xenoliths from the Kerguelen Islands |
title_full |
Plume-lithosphere interaction : geochemical evidence from upper mantle and lower crustal xenoliths from the Kerguelen Islands |
title_fullStr |
Plume-lithosphere interaction : geochemical evidence from upper mantle and lower crustal xenoliths from the Kerguelen Islands |
title_full_unstemmed |
Plume-lithosphere interaction : geochemical evidence from upper mantle and lower crustal xenoliths from the Kerguelen Islands |
title_sort |
plume-lithosphere interaction : geochemical evidence from upper mantle and lower crustal xenoliths from the kerguelen islands |
publisher |
Massachusetts Institute of Technology |
publishDate |
1999 |
url |
http://hdl.handle.net/1721.1/54434 |
geographic |
Kerguelen Heard Island Kerguelen Islands |
geographic_facet |
Kerguelen Heard Island Kerguelen Islands |
genre |
Heard Island Kerguelen Islands |
genre_facet |
Heard Island Kerguelen Islands |
op_relation |
http://hdl.handle.net/1721.1/54434 43855982 |
op_rights |
M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 |
_version_ |
1768388331255627776 |