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dc.contributor.authorPontbriand, Claire W.  Concept link
dc.coverage.spatialGakkel Ridge
dc.coverage.spatial85°E
dc.date.accessioned2013-02-12T18:48:58Z
dc.date.available2013-02-12T18:48:58Z
dc.date.issued2013-02
dc.identifier.urihttps://hdl.handle.net/1912/5761
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 2013en_US
dc.description.abstractSeafloor digital imagery and bathymetric data are used to evaluate the volcanic characteristics of the 85°E segment of the ultraslow spreading Gakkel Ridge (9 mm yr-1). Imagery reveals that ridges and volcanic cones in the axial valley are covered by numerous, small-volume lava flows, including a few flows fresh enough to have potentially erupted during the 1999 seismic swarm at the site. The morphology and distribution of volcaniclastic deposits observed on the seafloor at depths of ~3800 m, greater than the critical point for steam generation, are consistent with having formed by explosive discharge of magma and CO2 from source vents. Microearthquakes recorded on a 200 m aperture seismometer network deployed on the Trans-Atlantic Geotraverse active mound, a seafloor massive sulfide on the Mid-Atlantic Ridge at 26°N, are used to image subsurface processes at the hydrothermal system. Over nine-months, 32,078 local microearthquakes (ML = -1) with single-phase arrivals cluster on the southwest flank of the deposit at depths <125 m. Microearthquakes characteristics are consistent with reaction-driven cracking driven by anhydrite deposition in the shallow secondary circulation system. Exit fluid temperatures recorded at diffuse vents on the mound during the microearthquake study are used to explore linkages between seismicity and venting.en_US
dc.description.sponsorshipMy research was funded by a National Defense Science and Engineering Graduate Fellowship, the Woods Hole Oceanographic Institution Deep Ocean Exploration Institute fellowship, graduate support from the Woods Hole Oceanographic Institution Academic Programs Office, and NSF Award 0137329 for TAG active mound research (PI: Rob Sohn).en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherMassachusetts Institute of Technology and Woods Hole Oceanographic Institutionen_US
dc.relation.ispartofseriesWHOI Thesesen_US
dc.subjectVolcanic eruptionsen_US
dc.subjectVolcanologyen_US
dc.titleDeep explosive volcanism on the Gakkel Ridge and seismological constraints on shallow recharge at TAG active mounden_US
dc.typeThesisen_US
dc.identifier.doi10.1575/1912/5761


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