Geochemistry: The noble art of recycling.

The article addresses the origin of the air-like xenon component using the ratios of two further isotopes. The results from the radiogenic isotopes indicate that the air-crust hybrid component, which is likely to be added to well gases through local contamination during their storage in the continental crust, can account for only about half of the 90 percent atmospheric xenon component revealed by the non-radiogenic xenon isotopes. They have concluded that some air-like xenon in the New Mexico well-gas samples is intrinsic to their mantle source seems robust.