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Updated: Jul 12, 2026
07:48
An Externally-Heated Diamond Anvil Cell for Synthesis and Single-Crystal Elasticity Determination of Ice-VII at High Pressure-Temperature Conditions
Published on: June 18, 2020
Summary
South African diamonds contain helium-3/helium-4 ratios. Some diamonds show extremely high ratios, suggesting primitive helium that has evolved little since Earth's formation.
Area of Science:
- Geochemistry
- Isotope analysis
- Earth sciences
Background:
- Helium isotopes (Helium-3/Helium-4) provide insights into planetary evolution.
- Understanding helium origins is crucial for Earth and solar system science.
Purpose of the Study:
- To analyze the helium-3/helium-4 isotopic ratio in South African diamonds.
- To investigate the implications of observed ratios for Earth's primitive helium content.
Main Methods:
- Isotopic ratio analysis of helium-3 to helium-4.
- Sampled thirteen diamond stones from South African mines.
Main Results:
- Helium-3/Helium-4 ratios varied significantly, from <10(-7) to (3.2 ± 0.25) x 10(-4).
- The highest observed ratio exceeds the primordial ratio found in meteorites.
- The highest ratio is comparable to solar-type helium ratios.
Conclusions:
- Extremely high helium-3/helium-4 ratios in diamonds may indicate the presence of primitive helium.
- These findings suggest minimal evolution of helium-4 (radiogenic) since Earth's formation.
- Diamonds can serve as valuable samples for studying Earth's early isotopic composition.
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