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dc.contributor.authorFujiwara, Toshiya  Concept link
dc.contributor.authorLin, Jian  Concept link
dc.contributor.authorMatsumoto, Takeshi  Concept link
dc.contributor.authorKelemen, Peter B.  Concept link
dc.contributor.authorTucholke, Brian E.  Concept link
dc.contributor.authorCasey, John F.  Concept link
dc.date.accessioned2013-02-19T20:49:51Z
dc.date.available2013-02-19T20:49:51Z
dc.date.issued2003-03-08
dc.identifier.citationGeochemistry Geophysics Geosystems 4 (2003): 1024en_US
dc.identifier.urihttps://hdl.handle.net/1912/5774
dc.descriptionAuthor Posting. © American Geophysical Union, 2003. 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 4 (2003): 1024, doi:10.1029/2002GC000364.en_US
dc.description.abstractThe Mid-Atlantic Ridge around the Fifteen-Twenty Fracture Zone is unique in that outcrops of lower crust and mantle rocks are extensive on both flanks of the axial valley walls over an unusually long distance along-axis, indicating a high ratio of tectonic to magmatic extension. On the basis of newly collected multibeam bathymetry, magnetic, and gravity data, we investigate crustal evolution of this unique section of the Mid-Atlantic Ridge over the last 5 Ma. The northern and southern edges of the study area, away from the fracture zone, contain long abyssal hills with small spacing and fault throw, well lineated and high-amplitude magnetic signals, and residual mantle Bouguer anomaly (RMBA) lows, all of which suggest relatively robust magmatic extension. In contrast, crust in two ridge segments immediately north of the fracture zone and two immediately to the south is characterized by rugged and blocky topography, by low-amplitude and discontinuous magnetization stripes, and by RMBA highs that imply thin crust throughout the last 5 Ma. Over these segments, morphology is typically asymmetric across the spreading axis, indicating significant tectonic thinning of crust caused by faults that have persistently dipped in only one direction. North of the fracture zone, however, megamullions are that thought to have formed by slip on long-lived normal faults are found on both ridge flanks at different ages and within the same spreading segment. This unusual partitioning of megamullions can be explained either by a ridge jump or by polarity reversal of the detachment fault following formation of the first megamullion.en_US
dc.description.sponsorshipThis work was completed while T. Fujiwara was a Guest Investigator at Woods Hole Oceanographic Institution with funding from Japan Marine Science and Technology Center (JAMSTEC), National Science Foundation, and the JAMSTEC Research Overseas Program. J. Lin’s contributions to this research were supported by NSF Grant OCE-9811924. B. E. Tucholke’s contributions were supported by NSF Grant OCE-9503561 and by the Andrew W. Mellon Endowment Fund for Innovative Research and the Henry Bryant Bigelow Chair at Woods Hole Oceanographic Institution.en_US
dc.format.mimetypeapplication/pdf
dc.format.mimetypetext/plain
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2002GC000364
dc.subjectFifteen-twenty fracture zoneen_US
dc.subjectMorphologyen_US
dc.subjectMagnetic anomalyen_US
dc.subjectGravity anomalyen_US
dc.subjectMegamullionen_US
dc.titleCrustal Evolution of the Mid-Atlantic Ridge near the Fifteen-Twenty Fracture Zone in the last 5 Maen_US
dc.typeArticleen_US


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