Featured image: A close-up photograph of a layered rock formation. AI-generated image; not a photograph of the reported event.
A team from the University of Science and Technology of China has found Earth’s core is continuously leaking materials trapped since the planet formed.
What the Study Found
The research, published in Science Advances, focused on hydrogen movement through Earth’s layers.
Scientists used machine-learning-boosted ‘path-integral simulations’ to model how light atoms behave under extreme conditions.
Hydrogen, a key element from the solar nebula, was trapped deep in Earth’s core and mantle when the planet formed.
The study asked: Does today’s deep mantle reflect ancient magma ocean conditions—or has the core and mantle been exchanging materials for billions of years?
Key Results
- The deep mantle has a uniform hydrogen isotope ratio, not matching predictions from early crystallization models.
- The starting hydrogen composition in the magma ocean was the main factor shaping today’s mantle.
- Early water content—up to two ocean masses—had little effect on the final result.
- Light hydrogen in the mantle matches hydrogen escaping from the core.
How the Evidence Works
Three chemical signals point to ongoing core-mantle exchange:
Hydrogen Isotopes
Hydrogen from the solar nebula has escaped the core over billions of years.
As it rises through mantle plumes, it gets absorbed into minerals, enriching them with light hydrogen.
This lowers the deuterium-to-hydrogen ratio in deep mantle rocks.
The ratio’s consistency across regions suggests a steady, long-term leak—not a one-time event.
Helium Isotopes
Helium-3 is a light isotope from the Big Bang and solar nebula.
Helium-4 comes from radioactive decay in Earth’s upper layers.
Volcanic rocks from ocean islands—like those in Iceland and Baffin Island—show high helium-3 to helium-4 ratios.
This suggests helium-3 is escaping from the core and moving upward through the mantle.
Tungsten Isotopes
During early formation, tungsten was mostly pulled into the core.
Recent measurements show some primordial tungsten isotopes are now rising in mantle plumes.
This proves core material is being transferred to the mantle over time.
Why This Changes Our Understanding
Earth’s deep mantle is not a frozen archive of early days.
Instead, it’s a dynamic system where core materials are being slowly reintroduced.
The chemical signatures in the mantle reflect ongoing exchange, not ancient, unchanged conditions.
What’s Still Unknown
No direct measurements of Earth’s core exist.
Scientists rely on surface rocks and volcanic samples to infer core activity.
The simulations are strong, but depend on assumptions about early Earth’s heat and element distribution.
Scientists don’t know how much material is moving, or if the leak is growing or slowing.
The role of mantle convection and tectonics in this process remains unclear.
What’s Next
Future work will improve isotope measurements using deep-sea drilling and new volcanic sampling.
Real-time instruments for monitoring mantle plumes may offer clearer data.
Space missions studying other planets with deep cores could help validate Earth’s models.
The study was published in Science Advances and fact-checked by Fiona MacDonald. For more on Earth’s deep interior, see the original article at ScienceAlert. Stay updated with science news at sciencealert.com.
