2), and rejuvenated lavas have EM1 characteristics (see Methods). Figure 3: Relationship between He and Pb isotopic ratios in Samoan lavas. Figure 4: Conceptual model of the geochemical geometry ...

The Earth’s mantle seems like the probable culprit, but the scientists say that this doesn’t work with the particular isotopic ratios of helium, strontium, neodymium and lead that they detected.

Helium is used as a critical tracer throughout the Earth sciences, where its relatively simple isotopic systematics is used to trace degassing from the mantle, to date groundwater and to time the ...

A new analysis of ancient lava flows in the Canadian Arctic suggests helium trapped in Earth’s core could be slowly “leaking” into the mantle and then reaching the surface—an idea that ...

This isotope is found at a ratio of about one per 2,500 helium-4 ions, the latter being the common version of helium. The sun just released a burst of a rare form of helium known as helium-3 (3 He).