20 MA RECORD OF EOLIAN IRON AND PHOSPHORUS FLUXES TO THE SOUTH PACIFIC

Past climatic variability is the key to understanding current and future climate change. Factors such as weathering and erosion rates, as well as circulation changes in the atmosphere and the ocean play a crucial role in dust systematics – the avenue through which the open ocean gains much of its trace nutrients. Trace nutrients such as iron and phosphate, a macronutrient, often limit primary productivity in the open ocean, where organisms depend on these nutrients to thrive. Replenishment of trace nutrients is thought to be provided by dust fluxes to the open ocean and the eolian phosphorus flux is poorly constrained. Dust supply to the open ocean is controlled by multiple variables, such as wind speed, wind strength, and distance from the source. In studying dust flux to the open ocean by way of core sediment analysis we can gain insight into paleo-patterns of atmospheric and ocean circulation as well as changes in terrigenous provenance through time. A 14 meter long-core (MV0502-1JC) from Marlin Rise in the South Pacific, a site dominated by eolian deposition, has been analyzed to provide bulk sediment geochemistry and detailed phosphorus geochemistry for the past 20 Ma. Along with providing information on iron and phosphorous fluxes to the area, comparisons of radiogenic isotope ratios and mineralogic data from Stancin et al. (2008) will shed light on how provenance changes influence eolian nutrient fluxes to the ocean.