Nd-Sr isotopes in fossil fish debris from IODP Exp302 ...

• Main Authors: Gleason, James D, Thomas, Deborah J, Moore, Theodore C, Blum, Joel D, Owen, Robert M, Haley, Brian A
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2012
• Subjects: Integrated Ocean Drilling Program / International Ocean Discovery Program IODP; Arctic Ocean; Lomonosov Ridge
• Online Access: https://dx.doi.org/10.1594/pangaea.787111; https://doi.pangaea.de/10.1594/PANGAEA.787111

Strontium and neodymium radiogenic isotope ratios in early to middle Eocene fossil fish debris (ichthyoliths) from Lomonosov Ridge (Integrated Ocean Drilling Program Expedition 302) help constrain water mass compositions in the Eocene Arctic Ocean between 55 and 45 Ma. The inferred paleodepositional setting was a shallow, offshore marine to marginal marine environment with limited connections to surrounding ocean basins. The new data demonstrate that sources of Nd and Sr in fish debris were distinct from each other, consistent with a salinity-stratified water column above Lomonosov Ridge in the Eocene. The 87Sr/86Sr values of ichthyoliths (0.7079 - 0.7087) are more radiogenic than Eocene seawater, requiring brackish to fresh water conditions in the environment where fish metabolized Sr. The 87Sr/86Sr variations probably record changes in the overall balance of river Sr flux to the Eocene Arctic Ocean between 55 and 45 Ma and are used here to reconstruct surface water salinity values. The eNd values of ... : Supplement to: Gleason, James D; Thomas, Deborah J; Moore, Theodore C; Blum, Joel D; Owen, Robert M; Haley, Brian A (2009): Early to middle Eocene history of the Arctic Ocean from Nd-Sr isotopes in fossil fish debris, Lomonosov Ridge. Paleoceanography, 24(2), PA2215 ...