南秦岭耀岭河群裂谷型火山岩锆石U-Pb年代学  

Zircon U-Pb geochronology of rift-type volcanic rocks ofthe Yaolinghe Group in the South Qinling orogen

作　　者：李怀坤[1] 陆松年[1] 陈志宏[1] 相振群[1] 周红英[1] 郝国杰[1] 

机构地区：[1]中国地质调查局天津地质矿产研究所,天津300170

出　　处：《地质通报》2003年第10期775-781,共7页Geological Bulletin of China

基　　金：国土资源部国际合作与科技司科研项目(编号:2000305);国家自然科学基金委员会重点项目(编号:40032010-C);中国地质调查局综合研究项目(编号:200113900070)

摘　　要：南秦岭耀岭河群以变质基性火山岩为主,夹少量酸性火山岩和碎屑岩。基性火山岩和凝灰岩的TIMS法锆石U-Pb同位素年龄分别为808Ma±6Ma和746Ma±2Ma,表明耀岭河群主体形成于南华纪,西峡-淅川一带所谓的“武当岩群”明显年轻于中元古代武当岩群,应该属于耀岭河群。耀岭河群大陆裂谷型火山岩是全球Rodinia超大陆在新元古代晚期南华纪裂解过程中的产物,反映秦岭造山带和Rodinia超大陆的形成演化密切相关。The Yaolinghe Group in the South Qinling orogen is composed dominantly of basic volcanic rocks with minor acid volcanic rocks and clastic rocks. The TIMS U-Pb zircon ages of basic volcanic rocks and tuff are 808±6Ma and 746± 2Ma respectively, demonstrating that the main part of the Yaolinghe Group formed in the late Neoproterozoic Nanhuan Period, and that the so-called 'Wudang Group' occurring in the Xixia-Xichuan area is significantly younger than the genuine Mesoproterozoic Wudang Group-complex and should be part of the Yaolinghe Group. The volcanic rocks of continental rifting origin of the Yaolinghe Group were formed in the process of break-up of the supercontinent Rodinia in the late Neoproterozoic Nanhuaan Period, which reflects that the Qinling orogen is closely related with the evolution of the supercontinent Rodinia.

关 键 词：南秦岭 耀岭河群 裂谷型火山岩 TIMS法 锆石U—Pb年代学 超大陆裂解 RODINIA 

分 类 号：P588.14[天文地球—岩石学] P597.3[天文地球—地质学]