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dc.contributor.advisorHenry J.B. Dick.en_US
dc.contributor.authorStandish, Jared Jeffreyen_US
dc.contributor.otherWoods Hole Oceanographic Institution.en_US
dc.date.accessioned2006-11-07T16:52:37Z
dc.date.available2006-11-07T16:52:37Z
dc.date.copyright2006en_US
dc.date.issued2006en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/34665
dc.descriptionThesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2006.en_US
dc.descriptionIncludes bibliographical references.en_US
dc.description.abstractBetween 90-25° E on the ultraslow-spreading Southwest Indian Ridge lie two sharply contrasting supersegments. One 630 km long supersegment erupts N-MORB that is progressively enriched in incompatible element concentrations from east to west. The second 400 km long supersegment contains three separate volcanic centers erupting E-MORB and connected by long amagmatic accretionary segments, where mantle is emplaced directly to the seafloor with only scattered N-MORB and E-MORB erupted. Rather than a major break in mantle composition at the discontinuity between the supersegments, this sharp contrast in geometry, physiography, and chemistry reflects "source" versus "process" dominated generation of basalt. Robust along-axis correlation of ridge characteristics (i.e. morphology, upwelling rate, lithospheric thickness), basalt chemistry, and crustal thickness (estimated from gravity) provides a unique opportunity to compare the influence of spreading geometry and rate on MORB generation. What had not been well established until now is the importance of melting processes rather than source at spreading rates < 20 mm/yr.en_US
dc.description.abstract(cont.) Along the orthogonally spreading supersegment (14 mm/yr) moderate degrees of partial melting effectively sample the bulk mantle source, while on the obliquely spreading supersegment (7-14 mm/yr) suppression of mantle melting to low degrees means that the bulk source is not uniformly sampled, and thus "process" rather than "source" dominates melt chemistry.en_US
dc.description.statementofresponsibilityby Jared Jeffrey Standish.en_US
dc.format.extent286 p.en_US
dc.format.extent71489623 bytes
dc.format.extent71488786 bytes
dc.format.mimetypeapplication/pdf
dc.format.mimetypeapplication/pdf
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsM.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.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582
dc.subjectJoint Program in Oceanography.en_US
dc.subjectEarth, Atmospheric, and Planetary Sciences.en_US
dc.subjectWoods Hole Oceanographic Institution.en_US
dc.subject.lcshGeochemistryen_US
dc.titleThe influence of ridge geometry at the ultraslow-spreading Southwest Indian Ridge (9⁰-25⁰E) : basalt composition sensitivity to variations in source and processen_US
dc.typeThesisen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentJoint Program in Oceanography.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences.en_US
dc.contributor.departmentWoods Hole Oceanographic Institution.en_US
dc.identifier.oclc71197031en_US


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