georefid:2002-014646SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2002-014646<gco:CharacterString>Strike-parallel variations in clay minerals and fault vergence in the Cascadia subduction zone</gco:CharacterString>2002-01-01publicationgeorefid:2002-014646Underwood, Michael B.University of Missouri at Columbia, Department of Geological Sciences, Columbia, MO, United StatesauthorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)30 (2)155-158Clay minerals probably affect the zonation of mechanical properties within a thick unit of abyssal-plain deposits as they enter the Cascadia subduction zone. Landward-vergent thrust faults develop above a deeper decollement because smectite-rich mudrocks within that corridor release more water during clay dehydration, which in turn elevates pore pressure and reduces basal shear stress relative to wedge strength. Conversely, dilution of smectite by illite and chlorite increases the frictional coefficient, and fluid overpressure should drop where smectite dehydration is volumetrically reduced. Thus, thrust faults within chlorite-rich segments of the margin are seaward vergent.completedSolid-earth geophysicsOceanographyaccretionary wedgesCascadia BasinCascadia subduction zoneclastic rocksclay mineralogyclay mineralsdecollementDeep Sea Drilling Projectdeep-sea environmentdehydrationdiagenesisDSDP Site 174East PacificfaultsLeg 146Leg 168Leg 18marine environmentmarine sedimentsmudstoneNorth PacificNortheast PacificOcean Drilling ProgramODP Site 892Pacific Oceanplate boundariesplate tectonicspore pressuresedimentary rockssedimentssegmentationshear stresssheet silicatessilicatessmectitestrengthsubduction zonesthrust faultsurn:org.iodp:exp:146urnlargerWorkCitationcampaignurn:org.iodp:exp:168urnlargerWorkCitationcampaignurn:org.iodp:exp:18urnlargerWorkCitationcampaignurn:org.iodp:exp:18:site:174urnlargerWorkCitationstudyurn:org.iodp:exp:18urnlargerWorkCitationcampaignurn:org.iodp:exp:146:site:892urnlargerWorkCitationstudyurn:org.iodp:exp:146urnlargerWorkCitationcampaignEnglishgeoscientificInformation-126.2048-125.070544.402644.5330