THE NOBLE GASES AND COSMIC RAY EXPOSURE AGE FO THE NINGQIANG CHONDRITE

On the basis of study on petrology and chemical composition the Ningqiang chondrite is an anomalous CV3 chondrite (oxidized subgroup). It contains a high abundance of ag-gregational chondrules and a very low abundance of refractory inclusions. The isotopic abundances of the noble gases in bulk samples of the Ningqiang chondrite are measured. Ningqiang chondrite shows a cosmic ray exposure age of 42.2 ±4.0 Ma, the highest for CV3 chon-drites. The U/Th-⁴He age is 4170 ± 160 Ma whereas the ⁴⁰K-⁴⁰Ar age is 4260 ± 70 Ma which are similar to other CV3 chondrites such as Leoville.