Popis: |
We investigated noble gas (He, Ne, Ar, Kr and Xe) and nitrogen isotopic composition in the carbonaceous chondrite Bukhara (CV3). This is the first report of N and noble gases measured in the same aliquot of bulk sample among the CV3 chondrites. Isotopic compositions of noble gases are mixtures of solar wind and Q-gases. We derive cosmic ray exposure (CRE) age of 22.6 ± 4.0 Ma from cosmogenic 21Ne and 38Ar for Bukhara. Nitrogen abundance observed in Bukhara is lowest compared with the data from CV3 chondrites. We estimate the trapped nitrogen composition of δ15N = + 10.9 ± 1.6‰ for Bukhara, distinct from average (δ15N = - 16.3 ± 1.5‰) in the bulk CV3 chondrites. Bukhara shows signature of heavy nitrogen, which is distinct than the solar wind (SW) and Q-gas. Trapped nitrogen is mixture of the components, SW, Q and comet. It is observed that there is no correlation of nitrogen composition with N content in the CV3 chondrites. |