钙长辉长无球粒陨石 NWA 11586 稀有气体 及其年代学.

Howardite-Eucrite-Diogenite(HED) clan meteorites come from Vesta, and are the important window for studying the formation and evolution of the solar system and terrestrial planets. The noble gases are the key means to understand the impact and thermal history of HED meteorites and Vesta. This research work presents a detail study of the noble gas isotopes, cosmic-ray exposure(CRE) age and nominal gas retention age for the unbrecciated eucrite NWA 11586. The noble gas isotopes indicate that the He, Ne and Ar of NWA 11586 are mainly cosmogenic and radiogenic. The CRE age of this meteorite(38. 5±4. 1 Ma) is consistent with the ages of major impact events(35-41 Ma) of HEDs, indicating that it may be launched from Vesta or V-type asteroids at -40 Ma. The U, Th-4He(T4) and 40K-40Ar(T40) gas retention ages of NWA 11586 are 1 019±41 Ma and 3 041±77 Ma respectively, the reset may be caused by late thermal events. [ABSTRACT FROM AUTHOR]