Neodymium and Strontium chemistry of Arctic Ocean sediments

• Main Authors: Haley, Brian A, Frank, Martin, Spielhagen, Robert F, Eisenhauer, Anton
• Format: Dataset
• Language: English
• Published: PANGAEA 2008
• Subjects: 302-CompSite; Amundsen Basin; Arctic Coring Expedition; ACEX; ARK-VIII/3; ARK-XVII/2; COMPCORE; Composite Core; Exp302; Gakkel Ridge; Arctic Ocean; Giant box corer; GKG; Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP; KAL; Kasten corer; Lomonosov Ridge; Polarstern; PS19/157; PS19/166; PS19/178; PS19/186; PS19/189; PS19/194; PS19 ARCTIC91; PS2163-2; PS2171-1; PS2179-1; PS2185-3; PS2185-6; PS2186-5; PS2190-3; PS59/280-1; PS59/280-2; PS59 AMORE; SD; Secchi disk; Vidar Viking; Arctic; North Pole; amundsen basin; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.769604; https://doi.org/10.1594/PANGAEA.769604

The early oceanographic history of the Arctic Ocean is important in regulating, and responding to, climatic changes. However, constraints on its oceanographic history preceding the Quaternary (the past 1.8 Myr) have become available only recently, because of the difficulties associated with obtaining continuous sediment records in such a hostile setting. Here, we use the neodymium isotope compositions of two sediment cores recovered near the North Pole to reconstruct over the past ~5 Myr the sources contributing to Arctic Intermediate Water, a water mass found today at depths of 200 to 1,500 m. We interpret high neodymium ratios for the period between 15 and 2 Myr ago, and for the glacial periods thereafter, as indicative of weathering input from the Siberian Putoranan basalts into the Arctic Ocean. Arctic Intermediate Water was then derived from brine formation in the Eurasian shelf regions, with only a limited contribution of intermediate water from the North Atlantic. In contrast, the modern circulation pattern, with relatively high contributions of North Atlantic Intermediate Water and negligible input from brine formation, exhibits low neodymium isotope ratios and is typical for the interglacial periods of the past 2 Myr. We suggest that changes in climatic conditions and the tectonic setting were responsible for switches between these two modes.