georefid:2005-011223SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2005-011223A numerical model of diffusion limited dissolution from deep Atlantic carbonate sediment2003-01-01publicationgeorefid:2005-011223
Wright, Kirsten V.authordocumentHardcopy76 pp.Though hiatuses occur across the Atlantic throughout its history, mechanisms explaining time periods of missing sediment record are not clear. Atlantic seafloor below the CCD is overlain by water undersaturated with respect to CaCO (sub 3) , and dissolution of carbonate from the sediment would be limited by diffusion of ions toward the sediment water interface. The flux of Ca (super 2+) depends on the concentration gradient and diffusion coefficient. The concentration gradient can be estimated from DSDP measurements, but the diffusion coefficient is approximated by an empirical relationship, which depends on porosity. Porosity data allow fitting of a function dependent on depth. Based on these relationships, a one dimensional finite difference model was developed. It seems robust with respect to nearly all of the parameters, but appears to be most sensitive to porosity. Investigation of reaction limited dissolution at the sediment water interface was also performed. The removal of carbonate from the sediment column was minimal. For the 10,000 year time step, the reduction in thickness was on the order of microns, and was around 1% for the entire 100 Ma. This is not enough to create a noticeable hiatus.completedQuaternary geologyalkaline earth metalsAtlantic Oceanbathymetrycalciumcalcium carbonatecarbonate compensation depthcarbonate sedimentsCenozoicDeep Sea Drilling Projectdeep-sea environmentdiffusionfinite difference analysisHoloceneionsmarine environmentmarine sedimentsmetalsnumerical modelsone-dimensional modelsporosityQuaternarysea watersediment-water interfacesedimentssolutionthicknessunconformitiesEnglishgeoscientificInformation-80.000020.0000-60.000075.0000Atlantic Ocean