| 其他摘要 | Recently, the researches of meteorites are becoming more thoroughly and extensively as great numbers of meteorites were collected in Antarctica and hot desert. There are three parts in this dissertation about partial Antarctic meteorites and desert meteorites of China: 1) Classification of some meteorites in Antarctic Grove Mountains (GRV); 2) Experiment research on chemical separation and purification of cosmogenic radionuclides 10Be and 26Al in meteorites, and 3) Research on bulk compositions and cosmogenic radionuclides 10Be and 26Al in some Antarctic meteorites and desert meteorites of China.
1) Classification of some GRV meteorites
Petrography and mineral chemistry of 24 ordinary chondrites from the Grove Mountain, Antarctic, have been studied to identify their chemical-petrographic types. These meteorites samples were selected from a total of 4448 Grove Mountain meteorites collected during the 19th Chinese Antarctic Research Expedition. The chemical-petrographic types of these meteorites are: 1 H3 (GRV 021603), 2 H4 (GRV 020200 and GRV 021493), 4 H5 (GRV 020048, GRV 020078, GRV 020129 and GRV 020236), 2 H6 (GRV 020075 and GRV 020226), 1 L4 (GRV 021563), 8 L5 (GRV 020047, GRV 020283, GRV 020297, GRV 021547, GRV 021547, GRV 021581, GRV 021615 and GRV 023771), 5 L6 (GRV 020103, GRV 020155, GRV 021505, GRV 021711 and GRV 022171), 1 LL4 (GRV 020029) and 1 LL6 (GRV 021496). The comparison of chemical-petrographic types and mass distribution models on Antarctic GRV meteorites collected by Chinese researchers and US researchers was completed. It has shown that the Antarctic GRV meteorites have higher abundance of L group, and all of these samples have almost same mass distribution model.
2) Experiments of chemical separation and purification of cosmogenic radionuclides 10Be and 26Al in meteorites
According to the existed methods of chemical separation and purification of cosmogenic radionuclides in meteorites, 10Be and 26Al have been separated and purified successively by us with several experiments. The experiment methods have been advantaged, the volume of Be solution was changed from 120ml to 90ml. The blank sample and one Jilin meteorite were employed to verify the entire experiment process, the abundance of 10Be and 26Al were analyzed by accelerator mass spectrometry (AMS). The exposure age of Jilin meteorite in this experiment is 0.52Ma, which is in agreement with the published exposure age 0.4Ma of the second stage of Jilin meteorites. It approved that the experiment of chemical separation of cosmogenic radionuclides 10Be and 26Al is successful, as well as show the Jilin meteorite sample in this study belong to a second-exposure stage sample.
3) Researches on bulk composition and cosmogenic radionuclides 10Be and 26Al in some Antarctic meteorites and desert meteorites of China
13 GRV meteorites and 3 desert meteorites were analyzed in order to achieve their bulk compositions. The chemical analysis results have proved their classification of petrography and mineralogy is correct. The terrestrial age and exposure age of 4 GRV meteorites and 2 desert meteorites were estimated based on the experiment results of cosmogenic radionuclides 10Be and 26Al. The terrestrial age ranges from 0 - 0.23Ma, and exposure age from 2.09 - 3.04Ma. |
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