Noble gases in meteorites



The measurement of isotopic abundances of the noble gases in meteorites and other extraterrestrial samples became a large and active field during the past decade, especially within the last four years. The five stable noble gases proved to be excellent keys for unlocking the secrets of past physical events in the solar system and are used in studies of such diverse topics as elemental abundances, high- and low-energy nuclear reactions in the solar system, ages of meteorites and the elements, early element fractionation in planetary formation, and many others. For convenience of presentation, recent work in this area is divided in the following summary into four main topics: (1) trapped noble gases, (2) cosmic-ray interactions, radiation ages, and gas-retention ages, (3) extinct radionuclides, and (4) lunar studies. In both the text and the bibliography, emphasis is given to work performed in the United States.