georefid:2007-029098SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1130/G23165A.1<gco:CharacterString>Paleomagnetic evidence of large footwall rotations associated with low-angle faults at the Mid-Atlantic Ridge</gco:CharacterString>2007-01-01publicationgeorefid:2007-029098doi:10.1130/G23165A.1Garces, MiguelUniversity of Barcelona, Department of Stratigraphy, Paleontology and Marine Geosciences, Barcelona, SpainauthorGee, Jeffrey S.Scripps Institution of Oceanography, United StatesauthorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)35 (3)279-282Exposures of gabbros and mantle-derived peridotites at slow-spreading oceanic ridges have been attributed to extension on long-lived, low-angle detachment faults, similar to those described in continental metamorphic core complexes. In continental settings, such detachments have been interpreted as having originated and remained active at shallow dips. Alternatively, currently shallow dipping fault surfaces may have originated at moderate to steep dips and been flattened by subsequent flexure and isostatic uplift. While the latter interpretation would be more consistent with Andersonian faulting theory, it predicts large footwall tilts that have not been observed in continental detachment faults. Here we use the magnetization of oceanic gabbro and peridotite samples exposed near the Fifteen-Twenty Fracture Zone on the Mid-Atlantic Ridge to demonstrate that substantial footwall rotations have occurred. Widespread rotations ranging from 50 degrees to 80 degrees indicate that original fault orientations dipped steeply toward the spreading axis.completedSolid-earth geophysicsaccommodation zonesAtlantic Oceandetachment faultsfaultsFifteen-Twenty fracture zonefoot wallfracture zonesgabbrosigneous rocksLeg 209low-angle faultsmagnetic inclinationmagnetizationmetasomatismMid-Atlantic Ridgemid-ocean ridgesNorth AtlanticOcean Drilling ProgramODP Site 1270ODP Site 1271ODP Site 1272ODP Site 1274ODP Site 1275paleomagnetismperidotitesplate tectonicsplutonic rocksremanent magnetizationrotationsea-floor spreadingserpentinizationspreading centersultramaficsurn:org.iodp:exp:209urnlargerWorkCitationcampaignurn:org.iodp:exp:209:site:1270urnlargerWorkCitationstudyurn:org.iodp:exp:209urnlargerWorkCitationcampaignurn:org.iodp:exp:209:site:1271urnlargerWorkCitationstudyurn:org.iodp:exp:209urnlargerWorkCitationcampaignurn:org.iodp:exp:209:site:1272urnlargerWorkCitationstudyurn:org.iodp:exp:209urnlargerWorkCitationcampaignurn:org.iodp:exp:209:site:1274urnlargerWorkCitationstudyurn:org.iodp:exp:209urnlargerWorkCitationcampaignurn:org.iodp:exp:209:site:1275urnlargerWorkCitationstudyurn:org.iodp:exp:209urnlargerWorkCitationcampaignEnglishgeoscientificInformation-47.3000-44.300014.300016.0000With GSA Data Repository Item 2007050