Rare earth element and neodymium isotope tracing of element input and past ocean circulation: study from North and South Pacific seawater and sediments

• Main Author: Fröllje, Henning
• Format: Thesis
• Language: unknown
• Published: 2016
• Subjects: Chemistry; Pacific; North Atlantic
• Online Access: http://oops.uni-oldenburg.de/2865/; http://oops.uni-oldenburg.de/2865/1/frorar16.pdf

Neodymium (Nd) isotopes and rare earth elements (REE) were analysed in North Pacific seawater (near Hawaii) to investigate lithogenic input to the ocean. Further, Nd isotopes measured in South Pacific sedimentary archives were used to study changes in deep ocean circulation during the last 30,000 and 140,000 years. REE and Nd isotopes in seawater near Hawaii suggest a significant contribution of local (Hawaiian) and distal (Asian dust) sources to their budgets in the central North Pacific and seasonality of element supply. South Pacific sedimentary Nd isotope compositions reflect the changing deep water circulation and water mass mixing since the last and penultimate Glacial Maximum. They suggest a Southern Hemisphere climate control on early deglacial deep destratification in addition to the more general influence of varying fractions of North Atlantic and North Pacific deep waters on the deep water mixture in the South Pacific. A methodological approach shows the failure of common leaching protocols for the extraction of paleo-bottom water Nd isotope signals from deep South Pacific sedimentary ferromanganese oxides.