Neon isotopes in back-arc basins

In contrast (again) to the helium isotope database, neon data in BABB are sparse. To date, neon isotope results are available for the Lau Basin (Honda et al. 1993b), the Mariana Trough (Ikeda et al. 1998 Sano et al. 1998a) and the Manus Basin (Shaw et al. 

Most samples from the Mariana Trough (with the exception of one outlier) plot close to the MORB correlation line. 

The Lau Basin data lie on a linear trajectory slightly steeper than the MORB-line but nowhere near the Loihi-Kilauea (L-K) correlation lines. One sample from the Mariana Trough (which has the most extreme enrichments in °Ne/ Ne and 

The Manus Basin samples lie along a trajectory with a slope less than the MORB correlation line (the so-called Manus trend ). 

As all samples appear to follow linear trajectories in 3-isotope neon space, they must represent binary mixtures between two end-members with distinct neon isotope systematics. One end-member is clearly air reflecting the inevitable contamination of all terrestrial samples with atmospheric neon. The other end-member consists predominantly of mantle neon which is itself composed of a mixture of solar neon (high °Ne/ Ne 13.8) and nucleogenic neon (high Ne/ Ne)—in various proportions. 

---