Orca Basin, Gulf of Mexico Stable Isotope, Trace Metal and Geochemistry Data with SST and SSS Reconstructions over the last 17 ka Vetter, L.; Spero, H.J.; Eggins, S.M.; Williams, C.; Flower, B.P. Vetter, L. Spero, H.J. Eggins, S.M. Williams, C. Flower, B.P. Other Hydroclimate Reconstruction Sea Surface Temperature Reconstruction earth science/paleoclimate/climate reconstructions|paleoceanography (delta 18O,delta 18O|magnesium/calcium|sea water,null,per mil VSMOW,null,climate reconstructions|paleoceanography,null,null,N,Calculated water oxygen isotope value using calculated temperature and the formula of Bemis et al. 1998) earth science/paleoclimate/climate reconstructions|paleoceanography (delta 18O,delta 18O|magnesium/calcium|sea water,null,per mil VSMOW,null,climate reconstructions|paleoceanography,corrected,null,N,Estimated seawater oxygen isotope value when corrected for ice volume effects using the ice volume isotope offsets of Williams et al. 2012) earth science/paleoclimate/paleoceanography (magnesium/calcium,Orbulina universa,two standard deviations lower bound,millimole per mole,null,paleoceanography,null,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (barium/calcium,Orbulina universa,null,micromole per mole,null,paleoceanography,null,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,C,Core name collected aboard the RV Marion Dufresne) earth science/paleoclimate/paleoceanography (depth,null,null,meter,null,paleoceanography,null,null,C,mbsf) earth science/paleoclimate/climate reconstructions|paleoceanography (sea surface temperature,magnesium/calcium,null,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,Calculated temperature from measured Mg/Ca ratio using the relationship of Russell et al. 2004; Orbulina universa) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,N,Diameter of each specimen shell) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,N,Mass of each specimen after sonication in methanol Sartorius ultramicrobalance) earth science/paleoclimate/paleoceanography (delta 13C,Orbulina universa,null,per mil VPDB,null,paleoceanography,null,isotope ratio mass spectrometry,N,0.03 error; gas-source dual inlet stable carbon isotope measurement with ±0.03 per mil (‰) (2 SD)) earth science/paleoclimate/paleoceanography (magnesium/calcium,Orbulina universa,null,millimole per mole,null,paleoceanography,null,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (barium/calcium,Orbulina universa,two standard deviations upper bound,micromole per mole,null,paleoceanography,null,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (magnesium/calcium,Orbulina universa,two standard deviations upper bound,millimole per mole,null,paleoceanography,null,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,C,specimen number; Individual specimens of the planktic foraminiferal species O. universa were picked from the >350 µm size fraction and assigned specimen numbers) earth science/paleoclimate/climate reconstructions|paleoceanography (salinity,delta 18O|magnesium/calcium|sea surface,null,parts per thousand,null,climate reconstructions|paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (delta 18O,Orbulina universa,null,per mil VPDB,null,paleoceanography,null,isotope ratio mass spectrometry,N,0.06 error; gas-source dual inlet stable oxygen isotope measurement with ±0.06 per mil (‰) (2 SD)) earth science/paleoclimate/paleoceanography (barium/calcium,Orbulina universa,two standard deviations lower bound,micromole per mole,null,paleoceanography,null,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (MD02-2550>LATITUDE 26.9463>LONGITUDE -91.3458) Quantifying the history of meltwater oxygen isotope variability of the Laurentide Ice Sheet (LIS) across the last deglaciation could provide a powerful tool for exploring the dynamics of ice sheet melting during glacial terminations. Reconstructions of the glacial-interglacial rate of change in the d18Owater of the global ocean assume a homogeneous d18O value for contributions from individual ice sheets, such as the LIS. However, observations of the Greenland and Antarctic Ice Sheets indicate dynamic and highly variable melting. Here we present a series of snapshot records of the oxygen isotopic composition of LIS meltwater entering the Gulf of Mexico during discrete time slices of the last deglaciation (18 – 11 ka). We employ a novel technique that combines laser ablation ICP-MS (LA-ICP-MS) and oxygen isotope analyses on individual shells of the planktic foraminifer Orbulina universa to quantify the instantaneous d18Owater value of ice sheet meltwater. For each individual O. universa shell we measure Mg/Ca (a proxy for temperature) and Ba/Ca (a proxy for salinity) with LA-ICP-MS, and then analyze the same O. universa for d18O using the remaining material from the shell. From these proxies, we compute d18Owater and salinity for each individual foraminifer. A regression of all the data points obtained from the same core interval yields a d18Ow vs. salinity relationship with a y-intercept that gives the d18Ow composition of the freshwater end-member. Our data suggest that prior to Bølling-Allerød warming (before ~15.5 ka), the isotopic signature of Mississippi River outflow was dominated by regional precipitation, and that LIS meltwater did not play a significant role in salinity variation in surface waters overlying the Orca Basin. During the Bølling-Allerød (15.5 to 13 ka), computed d18Ow values of LIS meltwater from discrete core intervals range from -12‰ to -49‰ (VSMOW). These values indicate a dynamic melting history of different parts of the LIS, with potential contributions from both the low-elevation, southern margin of the LIS and high-elevation, high-latitude domes in the LIS interior. After 13 ka, our data do not suggest the presence of Mississippi River outflow over the Orca Basin; we hypothesize instead that open ocean conditions prevailed as sea level rose and the paleoshoreline at the southern edge of North America retreated northward. STUDY NOTES: Data from cores MD02-2550 and MD02-2551. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Vetter, L. Investigator : Spero, H.J. Investigator : Eggins, S.M. Investigator : Williams, C. Investigator : Flower, B.P. 2016-09-30 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/20550 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/vetter2016/vetter2016.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/vetter2016/vetter2016.txt English https://www.ncdc.noaa.gov/paleo/study/20550 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/vetter2016/vetter2016.txt Vetter, L., H.J. Spero, S.M. Eggins, C. Wiliams, and B.P. Flower2016A new method for reconstructing the oxygen isotopic composition of Laurentide Ice Sheet meltwater during the last deglaciationQuaternary Science Reviewsin revision START YEAR: 17420 cal yr BP * END YEAR: 0 cal yr BP -91.3458 26.9463 -91.3458 26.9463