Mantle Plume Helium in Submarine Basalts from the Galápagos Platform

• Published in: Science
• Main Authors: Graham, D. W., Christie, D. M., Harpp, K. S., Lupton, J. E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 1993
• Subjects: Iceland
• Online Access: http://dx.doi.org/10.1126/science.262.5142.2023; https://www.science.org/doi/pdf/10.1126/science.262.5142.2023

Helium-3/helium-4 ratios in submarine basalt glasses from the Galápagos Archipelago range up to 23 times the atmospheric ratio in the west and southwest. These results indicate the presence of a relatively undegassed mantle plume at the Galápagos hot spot and place Galápagos alongside Hawaii, Iceland, and Samoa as the only localities known to have such high helium-3/helium-4 ratios. Lower ratios across the rest of the Galápagos Archipelago reflect systematic variations in the degree of dilution of the plume by entrainment of depleted material from the asthenosphere. These spatial variations reveal the dynamics of the underlying mantle plume and its interaction with the nearby Galápagos Spreading Center.