georefid:2007-084822SEDIS 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/G23797A.1<gco:CharacterString>Dissolution of biogenic ooze over basement edifices in the Equatorial Pacific with implications for hydrothermal ventilation of the oceanic crust</gco:CharacterString>2007-01-01publicationgeorefid:2007-084822doi:10.1130/G23797A.1Bekins, Barbara A.U. S. Geological Survey, Menlo Park, CA, United StatesauthorSpivack, Arthur J.University of Rhode Island, United StatesauthorDavis, Earl E.Geological Survey of Canada, CanadaauthorMayer, Larry A.University of New Hampshire, United StatesauthorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)35 (8)679-682Recent observations indicate that curious closed depressions in carbonate sediments overlying basement edifices are widespread in the equatorial Pacific. A possible mechanism for their creation is dissolution by fluids exiting basement vents from off-axis hydrothermal flow. Quantitative analysis based on the retrograde solubility of calcium carbonate and cooling of basement fluids during ascent provides an estimate for the dissolution capacity of the venting fluids. Comparison of the dissolution capacity and fluid flux with typical equatorial Pacific carbonate mass accumulation rates shows that this mechanism is feasible. By maintaining sediment-free basement outcrops, the process may promote widespread circulation of relatively unaltered seawater in the basement in an area where average sediment thicknesses are 300-500 m. The enhanced ventilation can explain several previously puzzling observations in this region, including anomalously low heat flux, relatively unaltered seawater in the basement, and aerobic and nitrate-reducing microbial activity at the base of the sediments.completedOceanographyGeochemistry of rocks, soils, and sedimentsbioclastic sedimentationbiogenic processescarbonate sedimentsclastic sedimentscrustEquatorial Pacificgeochemistryheat fluxhydrothermal ventsLeg 138Leg 201marine sedimentsOcean Drilling Programoceanic crustODP Site 1226ODP Site 846oozePacific Oceanpelagic environmentquantitative analysissea watersediment-water interfacesedimentationsedimentation ratessedimentssolubilitythermal anomaliesventilationurn:org.iodp:exp:138urnlargerWorkCitationcampaignurn:org.iodp:exp:201urnlargerWorkCitationcampaignurn:org.iodp:exp:201:site:1226urnlargerWorkCitationstudyurn:org.iodp:exp:201urnlargerWorkCitationcampaignurn:org.iodp:exp:138:site:846urnlargerWorkCitationstudyurn:org.iodp:exp:138urnlargerWorkCitationcampaignEnglishgeoscientificInformation-110.3419-110.34002.46002.4614