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dc.contributor.authorHenig, A. S.
dc.contributor.authorBlackman, Donna K.
dc.contributor.authorHarding, Alistair J.
dc.contributor.authorCanales, J. Pablo
dc.contributor.authorKent, Graham M.
dc.date.accessioned2012-06-20T16:18:27Z
dc.date.available2014-10-22T08:57:24Z
dc.date.issued2012-05-19
dc.identifier.citationGeochemistry Geophysics Geosystems 13 (2012): Q0AG07en_US
dc.identifier.urihttp://hdl.handle.net/1912/5232
dc.descriptionAuthor Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 13 (2012): Q0AG07, doi:10.1029/2012GC004059.en_US
dc.description.abstractDetailed seismic refraction results show striking lateral and vertical variability of velocity structure within the Atlantis Massif oceanic core complex (OCC), contrasting notably with its conjugate ridge flank. Multichannel seismic (MCS) data are downward continued using the Synthetic On Bottom Experiment (SOBE) method, providing unprecedented detail in tomographic models of the P-wave velocity structure to subseafloor depths of up to 1.5 km. Velocities can vary up to 3 km/s over several hundred meters and unusually high velocities (~5 km/s) are found immediately beneath the seafloor in key regions. Correlation with in situ and dredged rock samples, video and records from submersible dives, and a 1.415 km drill core, allow us to infer dominant lithologies. A high velocity body(ies) found to shoal near to the seafloor in multiple locations is interpreted as gabbro and is displaced along isochrons within the OCC, indicating a propagating magmatic source as the origin for this pluton(s). The western two-thirds of the Southern Ridge is capped in serpentinite that may extend nearly to the base of our ray coverage. The distribution of inferred serpentinite indicates that the gabbroic pluton(s) was emplaced into a dominantly peridotitic host rock. Presumably the mantle host rock was later altered via seawater penetration along the detachment zone, which controlled development of the OCC. The asymmetric distribution of seismic velocities and morphology of Atlantis Massif are consistent with a detachment fault with a component of dip to the southeast. The lowest velocities observed atop the eastern Central Dome and conjugate crust are most likely volcanics. Here, an updated model of the magmatic and extensional faulting processes at Atlantis Massif is deduced from the seismic results, contributing more generally to understanding the processes controlling the formation of heterogeneous lithosphere at slow-rate spreading centers.en_US
dc.description.sponsorshipNSF support was provided via grant OCE-0927442.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttp://dx.doi.org/10.1029/2012GC004059
dc.subjectMid-Atlantic Ridgeen_US
dc.subjectDetachment faulten_US
dc.subjectGabbroen_US
dc.subjectOceanic core complexen_US
dc.subjectSeismic structureen_US
dc.subjectSerpentinized peridotiteen_US
dc.titleDownward continued multichannel seismic refraction analysis of Atlantis Massif oceanic core complex, 30°N, Mid-Atlantic Ridgeen_US
dc.typeArticleen_US
dc.description.embargo2012-11-19en_US
dc.identifier.doi10.1029/2012GC004059


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