Beam attenuation coefficient data from Vema ridge stations JC094-STN032 and JCO94-STN039 of the James Cook cruise JC094

The radiogenic isotope ratio 231Pa/230Th of seawater and ocean sediments is a potentially powerful tool for tracing oceanic processes such as the ocean circulation and marine primary productivity. However, 231Pa/230Th reflects the combined signal of multiple controls associated with scavenging and oceanic transport, limiting its use as a paleo-proxy. Given that links between seawater and sedimentary 231Pa and 230Th distributions are crucial for understanding the cycling and removal fluxes of these nuclides, we carry out analysis of 231Pa and 230Th in both seawater (dissolved phase) and modern sediment samples acquired from five depth transects across the northern tropical Atlantic open ocean during the JC094 research expedition which took place in October-November 2013. Measurements of the radiogenic isotopes were performed using a MultiCollector-Inductively Coupled Plasma-Mass Spectrometer (MC-ICP-MS). In addition, CTD beam attenuation coefficient measurements and XRF scan Fe and Ti measurements of two sediment cores collected from the region during the same research expedition are presented to aid interpretation of 231Pa and 230Th data. Here we show the CTD beam attenuation coefficient data near the Vema Fracture Zone.