Helium Isotopes and Helium and Carbon Dioxide Concentrations in Basaltic Vesicles and Glass from the Gulf of Aden

New helium isotope results for basalt glasses along the West and East Sheba Ridges in the Gulf of Aden reveal a strong mantle plume signal similar to that observed in the Main Ethiopian Rift, with 3He/4He ranging up to 17 Ra. This signal becomes fully attenuated by <400 km distance from the Afar triple junction. Eastward of the plume influence, from 45-56.5 degrees E, the Gulf of Aden shows uniform 3He/4He = 8.08+/-0.20 Ra (1 std dev, n=22). This region is the most uniform section of the global mid-ocean ridge system for helium isotopes at 100-1000 km length scales.