georefid:2002-012613SEDIS Publication Catalogue
ana.macario@awi.de
http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2002-012613<gco:CharacterString>Porosity loss within the underthrust sediments of the Nankai accretionary complex; implications for overpressures</gco:CharacterString>2002-01-01publicationgeorefid:2002-012613Screaton, ElizabethUniversity of Florida, Department of Geological Sciences, Gainesville, FL, United StatesauthorSaffer, DemianUniversity of Wyoming, United StatesauthorHenry, PierreEcole Normale Superieure, FranceauthorHunze, SabineGeowissenschaftliche Gemeinschaftsaufgaben, Federal Republic of GermanyauthorMoore, Gregory F.authorTaira, AsahikoauthorKlaus, AdamauthorBecker, KeirauthorBecker, LuannauthorBoeckel, BabetteauthorCragg, Barry A.authorDean, AllisonauthorFergusson, Christopher L.authorHirano, SatoshiauthorHisamitsu, ToshioauthorKastner, MiriamauthorMaltman, Alex J.authorMorgan, Julia K.authorMurakami, YukiauthorSanchez-Gomez, MarioauthorSmith, David C.authorSpivack, Arthur J.authorSteurer, JoanauthorTobin, Harold J.authorUjiie, KohtaroauthorUnderwood, Michael B.authorWilson, MoyraauthorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)30 (1)19-22Subduction complexes provide an opportunity to examine the interactions of deformation and fluid flow in an active setting. Ocean Drilling Program Leg 190 investigated the relationship between deformation, physical properties, and fluid flow in the toe of the Nankai Trough accretionary complex. With three sites (two from Leg 190, one from a previous leg) penetrating the decollement zone at various stages of development along the same transect, it is now possible to examine the change in porosity during rapid loading by trench turbidites and subsequent underthrusting. Results indicate inhibited dewatering and probable overpressure development seaward of the frontal thrust. Comparison of a reference site porosity versus depth curve to data from a site located within the protothrust zone indicates an overpressure ratio, lambda (super *) , of approximately 0.42, where lambda (super *) = [(pore pressure - hydrostatic pressure)/(lithostatic pressure - hydrostatic pressure)]. These overpressures suggest that the hemipelagic sediments have insufficient permeability for fluid escape to keep pace with the rapid loading by turbidite deposition within the trench. At a site 1.75 km farther arcward, an excess pore pressure ratio of lambda (super *) = approximately 0.47 was estimated, reflecting the additional loading due to recent thickening by the frontal thrust.completedSolid-earth geophysicsOceanographyaccretionary wedgescompactiondecollementdeformationfaultsfluid dynamicshemipelagic environmentLeg 131Leg 132Leg 190marine environmentmarine sedimentsNankai TroughNorth PacificNorthwest PacificOcean Drilling ProgramODP Site 1173ODP Site 1174ODP Site 808overpressurePacific Oceanpermeabilityphysical propertiesplate tectonicspore pressureporositysedimentsShikoku Basinsubductionthrust faultstroughsturbiditeunderthrust faultsWest Pacificurn:org.iodp:exp:131urnlargerWorkCitationcampaignurn:org.iodp:exp:132urnlargerWorkCitationcampaignurn:org.iodp:exp:190urnlargerWorkCitationcampaignurn:org.iodp:exp:190:site:1173urnlargerWorkCitationstudyurn:org.iodp:exp:190urnlargerWorkCitationcampaignurn:org.iodp:exp:196:site:1173urnlargerWorkCitationstudyurn:org.iodp:exp:196urnlargerWorkCitationcampaignurn:org.iodp:exp:190:site:1174urnlargerWorkCitationstudyurn:org.iodp:exp:190urnlargerWorkCitationcampaignurn:org.iodp:exp:131:site:808urnlargerWorkCitationstudyurn:org.iodp:exp:131urnlargerWorkCitationcampaignurn:org.iodp:exp:196:site:808urnlargerWorkCitationstudyurn:org.iodp:exp:196urnlargerWorkCitationcampaignEnglishgeoscientificInformation134.0000135.000032.000033.0000