Juan de Fuca Ridge Mass Flux Data over the Last 500 ka Costa, K.; McManus, J.F. Costa, K. McManus, J.F. earth science/paleoclimate/paleoceanography (age,null,null,calendar year before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (accumulation rate,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,mass flux) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (accumulation rate,sediment,two standard deviations,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,mass flux) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (AT26-19 05PC>LATITUDE 44.97283>LONGITUDE -130.8785) (AT26-19 38PC>LATITUDE 44.97053>LONGITUDE -130.60653) (AT26-19 12PC>LATITUDE 44.8975>LONGITUDE -130.50433) (AT26-19 35PC>LATITUDE 44.99118>LONGITUDE -130.45737) (AT26-19 39BB>LATITUDE 45.04507>LONGITUDE -130.83318) (AT26-19 09PC>LATITUDE 44.88717>LONGITUDE -130.63683) 230Th normalization is an indispensable method for reconstructing sedimentation rates and mass fluxes over time, but the validity of this approach has generated considerable debate in the paleoceanographic community. 230Th systematics have been challenged with regards to grain size bias, sediment composition (CaCO3), water column advection, and other processes. In this study, we investigate the consequences of these effects on 230Th normalization from a suite of six cores on the Juan de Fuca Ridge. The proximity of these cores (<30 km) suggests that they should receive the same particle rain rate of sediment, but the steep bathymetry of the ridge leads to substantial sediment redistribution and variable carbonate preservation, both of which may limit the usage of 230Th in this region. Despite anticipated complications, 230Th normalization effectively recon- structs nearly identical particle rain rates from all six cores, which are summarily unrelated to the total sedimentation rates as calculated from the age models. Instead the total sedimentation rates are controlled almost entirely by sediment focusing and winnowing, which are highly variable even over the short spatial scales investigated in this study. Furthermore, no feed- backs on 230Th systematics were detected as a consequence of sediment focusing, coarse fraction variability, or calcium car- bonate content, supporting the robustness of the 230Th normalization technique. STUDY NOTES: 11-Oct-17: Data table for 12PC updated to correct ordering of depths. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Costa, K. Investigator : McManus, J.F. 2016-12-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/21009 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-05pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-38pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-39bb.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-12pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-09pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-35pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-05pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-38pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-39bb.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-12pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-09pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-35pc.txt English https://www.ncdc.noaa.gov/paleo/study/21009 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-05pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-38pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-39bb.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-12pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-09pc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/costa2017/costa2017-35pc.txt Costa, K.M. and J.F. McManus2017Efficacy of 230Th normalization in sediments from the Juan de Fuca Ridge, northeast Pacific OceanGeochimica et Cosmochimica Acta197215-22510.1016/j.gca.2016.10.034 START YEAR: 16769 cal yr BP * END YEAR: 309737 cal yr BP -130.8785 44.88717 -130.45737 45.04507