Primordial neon in high-3He/4He Baffin Island olivines

Paleocene basaltic lavas exposed on Baffin Island have the highest 3He/4He found in any terrestrial igneous rocks and potentially contain most pristine primordial mantle material Earth's surface. By vacuum-crushing large (1–3 g) olivine mineral separates, we extracted enough magmatic gas to obtain first coupled helium, neon, argon isotopic compositions of lavas. The five samples ranging from 36.2 ± 0.6 48.6 1.3 (1σ) times atmospheric ratio (Ra), overlapping with known values. Neon results fall a mixing line between atmosphere high 20Ne/22Ne endmember (with maximum 12.2). slope this is indistinguishable that subglacial Holocene glass Iceland, but distinct other hotspots mid-ocean ridge basalt trends. This result supports hypothesis Iceland share common high-3He/4He component, despite fact recent paleogeographic reconstructions place hotspot far at time eruption (61 Ma). Our also demonstrate reservoirs 3He/22Ne variability either reflects ancient heterogeneity or helium addition upper lower mantle.