georefid:2013-047787SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.2204/iodp.sd.15.04.2013<gco:CharacterString>IODP Expedition 340T; Borehole logging at Atlantis Massif oceanic core complex</gco:CharacterString>2013-01-01publicationgeorefid:2013-047787doi:10.2204/iodp.sd.15.04.2013Blackman, DonnaScripps Institution of Oceanography, La Jolla, CA, United StatesauthorSlagle, AngelaLamont-Doherty Earth Observatory, United StatesauthorHarding, AlistairUniversity of Leeds, United KingdomauthorGuerin, GillesauthorMcCaig, AndrewauthorIntegrated Ocean Drilling Program Management International, Sapporo; Washington, DC, InternationalpublisherdocumentDigitalScientific Drilling1531-35Integrated Ocean Drilling Program (IODP) Expedition 340T returned to the 1.4-km-deep Hole U1309D at Atlantis Massif to carry out borehole logging including vertical seismic profiling (VSP). Seismic, resistivity, and temperature logs were obtained throughout the geologic section in the footwall of this oceanic core complex. Reliable downhole temperature measurements throughout and the first seismic coverage of the 800-1400 meters below seafloor (mbsf) portion of the section were obtained. Distinct changes in velocity, resistivity, and magnetic susceptibility characterize the boundaries of altered, olivine-rich troctolite intervals within the otherwise dominantly gabbroic sequence. Some narrow fault zones also are associated with downhole resistivity or velocity excursions. Small deviations in temperature were measured in borehole fluid adjacent to known faults at 750 mbsf and 1100 mbsf. This suggests that flow of seawater remains active along these zones of faulting and rock alteration. Vertical seismic profile station coverage at zero offset now extends the full length of the hole, including the uppermost 150 mbsf, where detachment processes are expected to have left their strongest imprint. Analysis of wallrock properties, together with alteration and structural characteristics of the cores from Site U1309, highlights the likely interplay between lithology, structure, lithospheric hydration, and core complex evolutioncompletedIgneous and metamorphic petrologyAtlantic OceanAtlantis Massifbody wavesboreholescorescrustelastic wavesExpedition 340TExpeditions 304/305igneous rocksIntegrated Ocean Drilling ProgramIODP Site U1309magnetic propertiesmagnetic susceptibilitymetamorphic core complexesMid-Atlantic RidgeNorth Atlanticoceanic crustP-wavespaleomagnetismplutonic rocksresistivityseismic wavesvelocitywell logsurn:org.iodp:exp:340TurnlargerWorkCitationcampaignurn:org.iodp:exp:304:site:U1309urnlargerWorkCitationstudyurn:org.iodp:exp:304urnlargerWorkCitationcampaignurn:org.iodp:exp:305:site:U1309urnlargerWorkCitationstudyurn:org.iodp:exp:305urnlargerWorkCitationcampaignurn:org.iodp:exp:340T:site:U1309urnlargerWorkCitationstudyurn:org.iodp:exp:340TurnlargerWorkCitationcampaignEnglishgeoscientificInformation-42.0700-42.060030.100030.1100application/x-unknown-media-typeunknownSEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContacthttp://www.iodp.org/doc_download/3649-sd15p3135exp340tpdfdownload