Excess xenon 129 and tellurium abundances in chondritic meteorites

Abstract

We have recently reported that the extinct nuclide I129 in meteorites appears to have been produced during the solar nucleosynthesis process, by the neutron-induced reactions and the relative contributions from (a) and (b) depending on the U/Te ratios in the meteoritic matters [Kuroda et al., 1966]. According to Wood [1966], the meteorite Renazzo represents a most primitive state of meteoritic matter. Reynolds and Turner [1964], however, showed that the I120−Xe129 formation intervals are substantially the same for chondrites like Renazzo, which apparently has not been metamorphosed at all, and a chondrite such as Bjurbole, whose cooling time is large compared with the mean life of I129. Thus, it was felt worth while to calculate the formation intervals of a number of meteorites, especially gas-rich carbonaceous chondrites, on the basis of the production of I129 according to equation a. In view of the ‘historic’ meaning of the expression ‘I129−Xe129 formation interval’ (referring to Xe129 formed by the decay of I129 from galactic nucleosynthesis) it seems appropriate to choose another expression for formation intervals calculated ,on the basis of equation a. Thus, we shall introduce here the new term ‘Te128−Xe129 formation interval.’