Petrogenesis of shield volcanism from the Juan Fernández Ridge, Southeast Pacific: Melting of a low-temperature pyroxenite-bearing mantle plume

The Juan Fernández Ridge (JFR) is an age-progressive volcanic chain (∼800 km long) related to a fixed mantle plume in the Southeast Pacific offshore central Chile. The high 3He/4He ratio (up to 18 times higher than that of the atmosphere) and spatiotemporal 40Ar/39Ar geochronology suggest that the source material of the JFR is derived from the lower mantle and transferred to the surface by a relatively stationary plume. We used new whole-rock...