Related Experiment Video
Updated: Jul 14, 2026

Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 16, 2013
Evolution of helium isotopes in the Earth's mantle
Cornelia Class1, Steven L Goldstein
1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA class@ldeo.columbia.edu
Abstract:
Degassing of the Earth's mantle through magmatism results in the irreversible loss of helium to space, and high (3)He/(4)He ratios observed in oceanic basalts have been considered the main evidence for a 'primordial' undegassed deep mantle reservoir. Here we present a new global data compilation of ocean island basalts, representing upwelling 'plumes' from the deep mantle, and show that island groups with the highest primordial signal (high (3)He/(4)He ratios) have striking chemical and isotopic similarities to mid-ocean-ridge basalts. We interpret this as indicating a common history of mantle trace element depletion through magmatism. The high (3)He/(4)He in plumes may thus reflect incomplete degassing of the deep Earth during continent and ocean crust formation. We infer that differences between plumes and the upper-mantle source of ocean-ridge basalts reflect isolation of plume sources from the convecting mantle for approximately 1-2 Gyr. An undegassed, primordial reservoir in the mantle would therefore not be required, thus reconciling a long-standing contradiction in mantle dynamics.
More Related Videos
Related Concept Videos
Isotopes
Noble Gases
The elements in group 18 are noble gases (helium, neon, argon, krypton, xenon, and radon). They earned the name “noble” because they were assumed to be nonreactive since they have filled valence shells. In 1962, Dr. Neil Bartlett at the University of British Columbia proved this assumption to be false.
Nuclear Stability
To hold positively charged protons together in the...
Nuclear Binding Energy
Nuclear Fusion
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
Mass Spectrometry: Isotope Effect

