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dc.contributor.authorXu, Min
dc.contributor.authorCanales, J. Pablo
dc.contributor.authorTucholke, Brian E.
dc.contributor.authorDuBois, David L.
dc.date.accessioned2010-04-21T19:17:02Z
dc.date.available2010-04-21T19:17:02Z
dc.date.issued2009-10-10
dc.identifier.citationGeochemistry Geophysics Geosystems 10 (2009): Q10001en_US
dc.identifier.urihttp://hdl.handle.net/1912/3297
dc.descriptionAuthor Posting. © American Geophysical Union, 2009. 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 10 (2009): Q10001, doi:10.1029/2009GC002586.en_US
dc.description.abstractThe Kane oceanic core complex (OCC) is a large, corrugated megamullion that was formed by a long-lived detachment fault at the axis of the Mid-Atlantic Ridge adjacent to Kane Fracture Zone between 2.1 and 3.3 Ma. We use refracted arrivals recorded along a 6-km-long hydrophone streamer during a multichannel seismic survey to constrain the shallow seismic velocity structure of the OCC. Results are presented in high-resolution traveltime seismic tomographic models along six lines that cover all of the main morphological features of the megamullion. The models show large lateral variability in P wave velocity within the upper ∼0.5–2.0 km of the lithosphere, and these variations correlate to first order with observed variations in lithology, documented by in situ basement samples and seafloor morphology. Lithological interpretation of the velocity models indicates that there is marked lateral variability in distribution of gabbroic intrusions, serpentinized peridotites, and basalts at scales of a few kilometers to ∼10 km. Serpentinized peridotites appear to dominate the central and older parts of the OCC. High-velocity gabbros are consistently (but not exclusively) present closer to the termination of the Kane detachment fault and toward the ends of the OCC. The structure of the lithosphere exhumed by the Kane detachment fault is far from the standard ophiolite-based Penrose model, and it does not show segment-centered magmatism that is commonly interpreted at slow spreading ridges. If the gabbros exhumed toward the termination of the OCC were emplaced deep (∼10 km) beneath the spreading axis, they may have constituted a weak zone that focused initiation of the Kane detachment fault. Alternately, as the OCC footwall was being exhumed the gabbros may have been emplaced because of dynamic changes in melt supply, changes in mantle fertility, or decompression melting. Late stage volcanism is clearly associated with a major high-angle normal fault that cuts the detachment surface; this volcanism may have been stimulated or enhanced by bending stresses in the bending footwall. The shape of the large-scale corrugated morphology of the OCC is nearly invariant in the dip direction across major changes in basement lithology, indicating that once established, the form of the Kane detachment fault was highly resistant to modification.en_US
dc.description.sponsorshipThis research was supported by NSF grants OCE-9987004 and OCE-0621660.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttp://dx.doi.org/10.1029/2009GC002586
dc.subjectKane oceanic core complexen_US
dc.subjectOcean crustal structureen_US
dc.subjectDetachment faultingen_US
dc.subjectMid-Atlantic Ridgeen_US
dc.subjectSeismic tomographyen_US
dc.subjectLithologyen_US
dc.titleHeterogeneous seismic velocity structure of the upper lithosphere at Kane oceanic core complex, Mid-Atlantic Ridgeen_US
dc.typeArticleen_US
dc.identifier.doi10.1029/2009GC002586


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