Plume-lithosphere interaction : geochemical evidence from upper mantle and lower crusal Xenoliths from the Kerguelen Islands
Hassler, Deborah R.
MetadataShow full item record
This study is a geochemical investigation ofthe 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.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 1999
Suggested CitationThesis: Hassler, Deborah R., "Plume-lithosphere interaction : geochemical evidence from upper mantle and lower crusal Xenoliths from the Kerguelen Islands", 1999-06, DOI:10.1575/1912/4750, https://hdl.handle.net/1912/4750
Showing items related by title, author, creator and subject.
Comprehensive study of a heavy fuel oil spill : modeling and analytical approaches to understanding environmental weathering Lemkau, Karin L. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2012-06)Driven by increasingly heavy oil reserves and more efficient refining technologies, use of heavy fuel oils for power generation is rising. Unlike other refined products and crude oils, a large portion of these heavy oils ...
Results of research on surface waves of the western North Atlantic. I. Investigation of bottom pressure fluctuations and surface waves. II. Results of sea surface roughness determinations in the vicinity of Woods Hole, Mass., and Bermuda Seiwell, Harry Richard (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1948-08)Part I: It is to be expected that in the future, measurements of pressure fluctuations beneath the ocean surface will provide basic data for solution of many practical problems on the state of the sea. As a result of the ...
Involvement of Cytochrome P450 1A in the toxicity of aryl hydrocarbon receptor agonists : alteration arachidonic acid metabolism and production of reactive oxygen species Schlezinger, Jennifer J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1998-08)Two cytochrome P4501A-dependent mechanisms of aryl hydrocarbon receptor (AhR) agonist toxicity were examined in the marine teleost scup (Stenotomus chrysops), alteration of arachidonic acid (AA) metabolism and production ...