Noble Gas Isotope Geochemistry in Volcanic and Geological Systems

Noble gas isotopes serve as powerful tracers of Earth’s interior processes, linking deep mantle dynamics, crustal evolution and surface environments. In volcanic settings, variations in helium, neon and argon isotopes reveal mixing between primordial mantle volatiles and radiogenic gases produced by uranium and thorium decay in the crust. These signals inform on mantle plume contributions at hotspots, magmatic degassing at mid-ocean ridges and volatile recycling at subduction zones. In continental regions, helium isotope ratios distinguish crustal from mantle-derived fluids, while neon and argon systematics help to constrain fluid migration pathways through fault networks. Beyond tectonic insights, noble gas geochemistry underpins assessment of volcanic hazards, informs models of deep carbon release and guides exploration for critical resources such as helium. Recent advances in high-precision mass spectrometry and coupled fluid-flux measurements have strengthened our understanding of volatile budgets, offering new constraints on the rates of deep carbon and noble gas exchange between lithosphere, atmosphere and hydrosphere. As concerns mount over climate forcing and strategic resource security, noble gas isotope studies are increasingly at the forefront of integrative Earth-system research.

Research from Nature Portfolio

Recent field campaigns in the Himalayan-Tibetan orogen have combined in-situ CO₂ flux measurements with helium isotope analyses to quantify metamorphic and mantle contributions to regional degassing. These studies demonstrate that underthrusting of the Indian plate drives massive crustal carbon mobilisation, with rift-segment emissions rivalling global mid-ocean-ridge outputs and highlighting active collisional belts as hitherto underappreciated carbon sources. Complementary work on hydrothermal fluids in the southeastern Tibetan Plateau employs helium-carbon-nitrogen systematics to map a lithospheric-scale fault network. Correlations between ³He/⁴He ratios and strain rates along the India-Asia convergence reveal mantle input into plateau growth dynamics, emphasising the role of deeply sourced volatiles in orogenic uplift and providing a template for linking geochemistry with geodynamics.

Noble Gas Isotope Geochemistry in Volcanic and Geological Systems publication trend

The graph below shows the total number of articles in noble gas isotope geochemistry in volcanic and geological systems across all publications each year (not limited to Nature Index journals).

Technical terms

Isotopic ratio: The proportion of one isotope to another of the same element, used to trace the origin and evolution of fluids.

Radiogenic: Referring to isotopes produced by radioactive decay, such as ⁴He from uranium and thorium.

Metamorphic decarbonation: Release of CO₂ during mineral reactions under high-pressure, high-temperature conditions in subducting slabs.

Degassing: Emission of volatile components from magma or heated crustal rocks to the surface or atmosphere.

Volatile budget: The balance of gases exchanged between Earth’s interior reservoirs (mantle, crust) and surface reservoirs (atmosphere, oceans).

References

1. Deep carbon recycling viewed from global plate tectonics. National Science Review (2024).
2. Massive crustal carbon mobilization and emission driven by India underthrusting Asia. Communications Earth & Environment (2024).
3. Linking deeply-sourced volatile emissions to plateau growth dynamics in southeastern Tibetan Plateau. Nature Communications (2021).
4. High helium reservoirs in the Four Corners area of the Colorado Plateau, USA. Chemical Geology (2022).