| dc.description.abstract | Dissolved Neodymium (Nd) in the ocean is often used as a water mass tracer to reconstruct what the oceanic circulation in a certain area may have looked like in the past (van de Flierdt et al. 2012). The incorporated Nd in fish debris, specifically teeth, generally retains a sound record of deep seawater (Martin and Scher 2003). However, continental input may alter or add to the dissolved Nd, which further leads to Nd isotopic compositions that reflect sediment input and not ocean circulation (van de Flierdt et al. 2012). Additionally, dispersed volcanic ash in the ocean affects the isotopic composition of pore water and the pore water Nd is incorporated into fish debris (Abbott et al. 2015). By understanding how volcanic ash input affects the dissolved Nd isotopic signal we can further elucidate how to successfully determine oceanic circulation changes over time in the North Pacific. Understanding the paleo-ocean circulation, and the factors and processes that drive and affect it, is necessary to understand the current state of the ocean, as well as how it may change in the future. This requires a comprehensive understanding of the components may alter the dissolved isotopic Nd signal, such as volcanic ash. Here we compare the Nd isotopic composition of fish debris with the isotopic composition across three leached sediment phases of the same site to establish an understanding of how volcanic ash input affects the Nd in fish debris, as well as the Nd isotopic composition in the North Pacific over time. It is necessary to understand and be able to account for the effect of volcanic ash input when using dissolved Nd as a water mass tracer in order to get an accurate representation of the paleo-ocean circulation in the North Pacific over time. My research focuses on sediment dating back to the Cretaceous period (125-180 Ma) using samples collected from Ocean Drilling Program (ODP) Site 1149 in the North Pacific. | en |
