新疆库鲁克塔格地区基性岩墙群氦氩同位素组成及其地质意义  

HELIUM AND ARGON ISOTOPIC COMPOSITIONS OF MAFIC DYKE SWARM AND ITS IMPLICATION FROM KULUKETAG, XINJIANG

作　　者：张志诚[1] 郭召杰[1] 刘玉琳[1] 刘树文[1] 

机构地区：[1]北京大学造山带与地壳演化教育部重点实验室,地球与空间科学学院,北京100871

出　　处：《新疆地质》2004年第1期12-15,共4页Xinjiang Geology

基　　金：国家重点基础研究规划项目(2001CB409804)资助

摘　　要：新疆库鲁克塔格阔克苏地区基性岩墙群由一系列北西向延伸的辉绿岩岩墙组成．测得辉绿岩^3He／^4He值为2．03×10^-7．1×10^-7．明显大于放射性成因的^3He／^4He值，远远小于地幔的^3He／^4He值．^40Ar／^36Ar值变化范围为803～1214，表现出明显的相对于空气的^40Ar过剩，^40Ar／^36Ar初始值为507．辉绿岩He、Ar同位素特征是原始地幔和放射性成因源或地壳源的混合结果，它可能与塔里木、天山构造带发育的早二叠世裂谷作用有关．同时也暗示，上述地区的裂谷作用可能受到更深层次的构造活动的控制．The mafic dykes are composed of a lot of northwest trend diabase in Kuokesu, Kuruktag region, Xingjiang. 3He/4He values of the dyke rocks are from 2.03×10-7 ~ 7.1×10-7, which are obviously bigger than the 3He/4He value that is formed by radioactivity, and much smaller than the 3He/4He value of the mantle. Their 40Ar/36Ar values range from 803 ~ 1 214, which have excess argon that is relative to 40Ar of the air, and the 40Ar/36Ar initial ratio is 507. The isotope compositions of helium and argon of the mafic dyke rocks are mixed with the enrichment mantle and upper crust, which is potentially associated with early Permian rifting of Tarim basin and Tianshan tectonic belts. This imply that the rifting of Tarim basin and Tianshan tectonic belts is controlled by tectonic movement occurring much deep level of the Earth.

关 键 词：地壳 地幔 岩石 稀有气体同位素 基性岩墙群 氦 氩同位素 

分 类 号：P597[天文地球—地球化学]