RR25 Edwards

Ocean islands, such as Cape Verde, erupt a specific type of basalt termed ocean island basalt, or OIB. These are relatively enriched melts from the mantle, compared with mid-ocean ridge basalts. It has been shown that OIB provide an exclusive look into the composition of deep mantle source reservoirs (Hofmann, 1997; Stracke, 2012). Compared with volcanic rocks that form at convergent plate boundaries, OIB also undergo relatively less modification, such as crustal assimilation, and are widely considered direct mantle ‘probes’(e.g., Weis et al., 2011; Jackson et al., 2018; Doucet et al., 2020; Day et al., 2022). Overall, Cape Verde seamounts are under sampled, and the collection of rock and glass samples, in addition to bathymetric mapping would improve our understanding of this OIB province. We will target samples for 40Ar-39Ar age dating and geochemistry (major and trace elements, Sr-Nd-Pb-Os isotopes, all done at SIO) to unravel the geochemical disparity between the northern and southern islands, provide insight into the contrasting composition of Cadamosto Seamount, and resolve the mantle reservoir(s) that Cape Verde is sourcing. This work will aid in understanding past eruption styles in Cape Verde, including both subaerial and submarine, which pose hazards to human health and safety.