西藏措勤-赛利普地区新生代火山岩同位素组成及源区性质探讨  

CENOZOIC VOLCANIC ISOTOPIC COMPOSITION AND SOURCE AREAQUALITV,THE CUOQIN-SAILIPU AREA OF THE WESTERN IN TIBETAN PLATEAU

作　　者：岳相元[1] 马润则[1] 付小文[1] 韩文文[1] 李湘玉[1] 

机构地区：[1]成都理工大学地球科学学院,四川成都610059

出　　处：《新疆地质》2011年第4期457-461,共5页Xinjiang Geology

基　　金：矿物学;岩石学;矿床学国家重点(培育)学科建设基金项目(SZD0407);中国地质调查局区域地质调查项目资助

摘　　要：对赛利普地区新生代火山岩Sr,Nd,Pb同位素资料分析,揭示了赛利普新生代火山岩同位素组成在时代和岩石组合上存在的规律性变化.总体上,随时代变新,Sr,Pb同位素呈递增,Nd同位素呈递减趋势,火山岩中地壳物质贡献明显增加.本区新生代火山岩与青藏高原北部(班公湖-怒江缝合带以北)相比,Sr,Nd和Pb同位素组成存在一定差异,尤其是新近纪以来钾质火山岩显著高87Sr/86Sr、极低143Nd/144Nd值,208Pb/204Pb值普遍偏高,古近纪火山岩这种差别则不明显.揭示了新生代以来,在印度大陆岩石圈向北俯冲过程中,拉萨地块比青藏高原北部融入了更多喜马拉雅大陆地壳端元成分.中新世早中期,印度大陆板块向北A型俯冲到拉萨地块基底西段,并发生岩石圈不同层次部分熔融、岩石圈断离等作用.This paper based on the results of the Sr, Nd, Pb isotope data analysis in Cuoqin-Sailipu area,revealing that the cenozoic volcanic isotopic composition of era and rock assemblages exist on a regular change.Over all,as the era of variable fresh, Sr, Pb isotope is increment and Nd isotope is degressive, volcanic rock crustal material contribution is increased obviously.compared Cenozoic volcanic rock with northern of Tibetan plateau area, Sr, Nd and Pb isotope composition is some difference,Especially in neogene the potassium to pledge volcanic significantly 87Sr/86Sr is more higher and 143Nd/144Nd is more lower,208pb / 204Pb is high.but this difference is not obvious on paleogene volcanic.This is to show the Lhasa block absorbs more components of Himalayan continent curst end than those in north of Qing-hai Tibet plateau in the northward subduction process of Cenozoic India continental lithosphere;In the early and mid Miocene, Indian continent had already subducted with A type nortbward to Lhasa block western basement fault and had functions on lithosphere partial melting and lithosphere iridodialysis on different levels of rocks.

关 键 词：青藏高原 赛利普地区 拉萨地块 新生代火山岩 SR-ND-PB同位素 

分 类 号：P534.6[天文地球—古生物学与地层学] P588.14[天文地球—地质学]