极地研究

极地研究 ›› 2006, Vol. 18 ›› Issue (3): 157-165.

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我国南极橄辉无球粒陨石(GRV 024516)和H5球粒陨石(GRV 024517)宇宙射线暴露年龄和气体保存年龄

王道德;缪秉魁;林杨挺;   

  • 出版日期:2006-09-30 发布日期:2006-09-30

COSMIC-RAY EXPOSURE AGES AND GAS RETENTION AGES OF UREILITE(GRV 024516)AND ORDINARY CHONDRITE(GRV 024517)FROM ANTARCTICA

  • Online:2006-09-30 Published:2006-09-30

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1516

被引次数

22

摘要：

我国在南极格罗夫山陨石富集区回收的GRV024516和GRV024517陨石样品分别为橄辉无球粒陨石和H5普通球粒陨石,在矿物-岩石学研究的基础上测定和计算了这两个陨石的宇宙射线暴露年龄和气体保存年龄,其宇宙射线暴露年龄分别为33.3Ma和51.7Ma,气体保存年龄分别为1936.8Ma和3720Ma。橄辉无球粒陨石含金刚石、石墨和无定型碳,并为主要稀有气体的载体,且冲击变质效应明显,导致40Ar部分丢失。H5球粒陨石主要显示其母体内的热变质效应,其气体保存年龄落在未受严重冲击的H5球粒陨石范围(3220—4510Ma)内。

关键词: 陨石;球粒陨石;无球粒陨石;稀有气体;宇宙成因核素

Abstract:

The GRV 024516 and GRV 024517 meteorite samples collected from Grove Montains,Antactica are ureilite and H5 ordinary chondrite,respectively.Based on the study of mineralogy-petrology we determined and calculated cosmic-ray exposure ages and gas retention ages of these two meteorites.The cosmic-ray exposure ages are 33.3Ma and 51.7Ma,respectively.The gas retention ages are 1936.8Ma and 3720 Ma,respectively.Ureilite contains diamond,graphite and amorphous C,which are the main carrier of noble gases and shows shock metamorphism effects,which induced 40Ar partial loss.The H5 chondrite indicates thermal metamorphism of parent body,and its gas retention age falls between 3220Ma and 4510Ma of the least shocked H5 chondrites.