2008), Salinity of the Eocene Arctic Ocean from oxygen isotope analysis of fish bone carbonate, Paleoceanography 23

[1] Stable isotope analysis was performed on the structural carbonate of fish bone apatite from early and early middle Eocene samples (55 to 45 Ma) recently recovered from the Lomonosov Ridge by Integrated Ocean Drilling Program Expedition 302 (the Arctic Coring Expedition). The d18O values of the Eocene samples ranged from 6.84 % to 2.96 % Vienna Peedee belemnite, with a mean value of 4.89%, compared to 2.77 % for a Miocene sample in the overlying section. An average salinity of 21 to 25 % was calculated for the Eocene Arctic, compared to 35 % for the Miocene, with lower salinities during the Paleocene Eocene thermal maximum, the Azolla event at 48.7 Ma, and a third previously unidentified event at 47.6 Ma. At the Azolla event, where the organic carbon content of the sediment reaches a maximum, a positive d13C excursion was observed, indicating unusually high productivity in the surface waters. Citation: Waddell, L. M., and T. C. Moore (2008), Salinity of the Eocene Arctic Ocean from oxygen isotope analysis of fish bone carbonate, Paleoceanography, 23, PA1S12, doi:10.1029/2007PA001451. 1