钙长辉长无球粒陨石NWA 12274/12275/12276/12277/12278稀有气体及年代学研究  

The Noble Gas and Chronological Study of the Eucrites NWA 12274/12275/12276/12277/12278

作　　者：张川统 缪秉魁[1,4] 贺怀宇 苏菲[5] 解庆林[3] ZHANG Chuan-tong;MIAO Bing-kui;HE Huai-yu;SU Fei;XIE Qing-lin(Institution of Meteorites and Planetary Materials Research,Guilin University of Technology,Guilin Guangxi 541006,China;Key Laboratory of Lunar and Deep Space Exploration,Chinese Academy of Sciences,Beijing 100101,China;College of Environmental Science and Engineering,Guilin University of Technology,Guilin Guangxi 541006,China;Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration,Guilin Guangxi 541006,China;Key Laboratory of Earth and Planetary Physics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]桂林理工大学陨石与行星物质研究中心,广西桂林541006 [2]中国科学院月球与深空探测重点实验室,北京100101 [3]桂林理工大学环境科学与工程学院,广西桂林541006 [4]广西隐伏金属矿产勘查重点实验室,广西桂林541006 [5]中国科学院地质与地球物理研究所,地球与行星物理重点实验室,北京100029

出　　处：《矿物岩石地球化学通报》2021年第5期1143-1153,共11页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：中国科学院战略性先导科技专项(B类)(XDB41000000);中国博士后科学基金项目(2020M673557XB);民用航天技术预先研究项目(D020302,D020206);广西自然科学基金项目(2021GXNSFBA075061)。

摘　　要：岩石矿物学研究发现HED(Howardite-Eucrite-Diogenite)族陨石NWA 12274/12275/12276/12277/12278与NWA 11586可能为成对陨石,但需要稀有气体等证据支持。本次工作对这5块陨石开展了稀有气体、宇宙暴露(CRE)年龄和气体保存年龄研究。结果发现它们具有相一致的稀有气体同位素比值和CRE年龄,表明NWA系列陨石互为降落成对陨石;陨石CRE年龄[(36.2±3.7)Ma]与灶神星主要溅射事件/时期年龄(35.0~42.5 Ma)一致,表明它们可能在约36 Ma前从灶神星或V型小行星溅离;陨石的U、Th-^(4)He(T4)及^(40)K-^(40)Ar(T_(40))气体保存年龄分别为0.3~1.3 Ga和2.8~3.4 Ga,显示这些陨石不同程度受到了后期热事件的影响;该流星体进入大气层的初始半径约为12.2 cm,在穿越大气层期间质量损失了约56%。The petrological and mineralogical studies of NWA 12274/12275/12276/12277/12278 and NWA 11586 meteorites of the HED(Howardite-Eucrite-Diogenite)clan suggest that they may be paired,though it is necessary to be verified through other evidences such as the noble gas.This research work presents a comprehensive study of the noble gas isotopes,cosmic-ray exposure(CRE)ages and nominal gas retention ages for these five meteorites.The similar noble gas isotopic ratios and CRE ages indicate that the NWA series of meteorites are paired with each other.The CRE age(36.2±3.7 Ma)of the paired meteorites is consistent with those of the main ejection events/periods(35.0-42.5 Ma)on Vesta,suggesting that these meteorites could have been launched from the Vesta or V-type asteroids at~36 Ma.The U,Th-^(4)He(T_(4))and;^(40)K-^(40)Ar(T_(40))gas retention ages of these meteorites are 0.3-1.3 Ga and 2.8-3.4 Ga,respectively,indicating that these meteorites were obviously affected by late thermal events to varying degrees.The meteoroid had a preatmospheric radius of approximate 12.2 cm and about 56%of its mass was lost during its passage through the atmosphere of the Earth.

关 键 词：HED族陨石 稀有气体 宇宙暴露年龄 气体保存年龄 成对陨石 

分 类 号：P185.83[天文地球—天文学]