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dc.contributor.authorJackson, Matthew G.  Concept link
dc.coverage.spatialSamoa
dc.date.accessioned2008-05-12T20:10:20Z
dc.date.available2008-05-12T20:10:20Z
dc.date.issued2008-02
dc.identifier.urihttps://hdl.handle.net/1912/2217
dc.descriptionSubmitted 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 February 2008en
dc.description.abstractChapter 1 presents the first published measurements of Sr-isotope variability in olivine-hosted melt inclusions. Melt inclusions in just two Samoan basalt hand samples exhibit most of the total Sr-isotope variability observed in Samoan lavas. Chapter 3 deals with the largest possible scales of mantle heterogeneity, and presents the highest magmatic 3He/4He (33.8 times atmospheric) discovered in Samoa and the southern hemisphere. Along with Samoa, the highest 3He/4He sample from each southern hemisphere high 3He/4He hotspot exhibits lower 143Nd/144Nd ratios than their counterparts in the northern hemisphere. Chapter 2 presents geochemical data for a suite of unusually enriched Samoan lavas. These highly enriched Samoan lavas have the highest 87Sr/86Sr values (0.72163) measured in oceanic hotspot lavas to date, and along with trace element ratios (low Ce/Pb and Nb/U ratios), provide a strong case for ancient recycled sediment in the Samoan mantle. Chapter 4 explores whether the eclogitic and peridotitic portions of ancient subducted oceanic plates can explain the anomalous titanium, tantalum and niobium (TITAN) enrichment in high 3He/4He ocean island basalts (OIBs). The peridotitic portion of ancient subducted plates can contribute high 3He/4He and, after processing in subduction zones, a refractory, rutile-bearing eclogite may contribute the positive TITAN anomalies.en
dc.description.sponsorshipFunding was provided by a National Science Foundation Graduate Research Fellowship, the National Science Foundation grants EAR- 0509891 and EAR-0652707 to Stanley R. Hart, the Woods Hole Oceanographic Institution Academic Programs Office, the Woods Hole Oceanographic Institution Deep Ocean Exploration Institute, the Woods Hole Oceanographic Institution Coastal Ocean Institute, and the Ocean Ventures Fund.en
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen
dc.publisherMassachusetts Institute of Technology and Woods Hole Oceanographic Institutionen
dc.relation.ispartofseriesWHOI Thesesen
dc.subjectSubmarine geologyen_US
dc.subjectOphiolitesen_US
dc.titleDismantling the deep earth : geochemical constraints from hotspot lavas for the origin and lengthscales of mantle heterogeneityen
dc.typeThesisen
dc.identifier.doi10.1575/1912/2217


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