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

Abstract: 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.