Rare gas studies of sixteen stony meteorites from Antarctica

The concentrations of rare gases and isotopic compositions of He, Ne and Ar were determined for fourteen chondrites and two achondrites from Antarctica. The Xe isotopic ratios were also determined for seven meteorites. Cosmic-ray exposure and gas retention ages are given. Exposure age of 55Ma determined for Y-75015 eucrite is longer than those for most eucrites so far reported. Xe contained in chondrites is a mixture of cosmogenic and trapped components. ^(Xe) excess from extinct ^I was found for these chondrites. In Y-75015 eucrite, trapped and cosmogenic Xe\u27s were dominant and an appreciable amount of fissiogenic Xe was detected. Five groups of paired meteorites are suggested on the basis of rare gas data