Magmatic rocks in the Charlie-Gibbs Fracture Zone, North Atlantic Ocean

Two basalt groups corresponding to different geodynamic environments were distinguished based on results of additional geochemical studies of materials obtained during Cruise 15 of the R/V Akademik Kurchatov and literature data on the Charlie-Gibbs Fracture Zone: (1) predominantly low-Ti tholeiites that are most closely similar to spreading basalts generated during the initial opening of the North Atlantic (southeastern margin of Greenland and the Vöring and Rockall plateaus) and (2) high-Ti differentiated basalts of variable alkalinity, which are deep, low-volume partial melts likely derived with the participation of a mantle plume. Compositional variations in the basalts were studied in the active and passive parts of the fracture zone. Our results bridge the gap in detailed geochemical data on oceanic crustal rocks and can be used in reconstructions of ancient geodynamic environments.