ABSTRACT

Isotopic anomalies observed in meteorites for O, Mg, Ca, Xe, Ba, Nd and U can be attributed to a combined effect of mass fractionation, neutron capture and cosmic-ray irradiation processes which took place prior to and during the formation of the solar system. The total cosmic-ray neutron flux (time integrated) appears to have been such that the isotopic compositions of a number of elements were altered appreciably.