Cosmic-ray exposure and gas retention ages of the Guang-mingshan(H5) chondrite  

作　　者：WANG Daode LIN Yangting LIU Jinyuan 

机构地区：[1]Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China [2]Dalian Museum of Natural History,Dalian 116023,China

出　　处：《Chinese Science Bulletin》2001年第18期1544-1546,共3页

基　　金：This work was supported by theNational Natural Science Foundation for Distinguished Young Scholars (Grant No. 40025311).

摘　　要：Isotopic compositions of noble gases from the Guangmingshan chondrite were analyzed. Based on the analyses of cosmogenic nuclei, cosmic-ray exposure age of the meteorite is (65±10.0) Ma (3He), (80±12) Ma (21Ne) and (65±10.0) Ma (38Ar), with an average of 70 Ma. This is the highest exposure age of H-group ordinary chondrites. Gas retention ages of K-Ar and U, Th-4He are (4230±100) Ma and (3300±60) Ma, respectively. The smaller ages of 3He than 21Ne and 4He than Ar suggest that both 3He and 4He lost together. This is probably related to a solar heating effect of a meteorite with a small perihelion during the last exposure period.Isotopic compositions of noble gases from the Guangmingshan chondrite were analyzed. Based on the analyses of cosmogenic nuclei, cosmic-ray exposure age of the meteorite is (65±10.0) Ma (3He), (80±12) Ma (21Ne) and (65±10.0) Ma (38Ar), with an average of 70 Ma. This is the highest exposure age of H-group ordinary chondrites. Gas retention ages of K-Ar and U, Th-4He are (4230±100) Ma and (3300±60) Ma, respectively. The smaller ages of3He than21Ne and4He than40Ar suggest that both3He and4He lost together. This is probably related to a solar heating effect of a meteorite with a small perihelion during the last exposure period.

关 键 词：NOBLE GAS COSMIC-RAY EXPOSURE age METEORITE CHONDRITE Zhuanghe Liaoning. 

分 类 号：P185[天文地球—天文学]