ABSTRACT

Xenon in the solar system can be divided into two groups: (a) primordial xenon, whose isotopic composition can be approximated by that of the atmospheric xenon and (b) xenon, whose isotopic composition was severely altered by high energy proton and neutron reactions which took place during the T-Tauri phase of our Sun. The isotopic compositions of the SUCOR (surface correlated) xenon found in lunar fines and the CCFX xenon, corrected for mass fractionation and spallation effects, belong to the group (a) and the AVCC xenon and the so-called s-type xenon found in the Murchison meteorite belong to the group (b). Some of the xenon fractions recently isolated from the Allende and Belgica meteorites appear to be more ‘primordial’ than the atmospheric xenon.