Isotope abundances of rare-earth elements in meteorites: 1. Implications of samarium, europium, and gadolinium to the early history of the solar system

摘要: The isotope abundances of samarium, europium, and gadolinium have been measured in two normal chondrites, an achondrite. a carbonaceous chondrite, volcanic basalt originating from depth 40 km the Kilauea-Iki vent Hawaii. meteoritic are similar to terrestrial within experimental errors, general'' or special'' anomalies for these three elements meteorites do not seem exist. There is no depletion isotopes with large thermal-neutron capture cross section (Sm/ sup 140/, Eu/sup 151/, Gd/sup 157/) relative earth. With reference recent theory which attributes D, Li, Be, B spallation irradiation, our data can be discussed as follows (1) neutrons produced processes were thermalized, so that rare-earth unaffected: (2) if ratio irradiated material nonirradiated exactly same earth meteorites: (3) there was significant irradiation. These alternatives some studies meteorites. (auth)