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| 唐古拉地区尕羊晚二叠世碰撞型花岗岩的确定和构造意义 | |
| 引用本文： | 祁生胜,王毅智,何世豪,宋生春,祁正林,王福林.唐古拉地区尕羊晚二叠世碰撞型花岗岩的确定和构造意义[J].西北地质,2009,42(3):26-35. |
| 作者姓名： | 祁生胜 王毅智 何世豪 宋生春 祁正林 王福林 |
| 作者单位： | 1. 青海省地质调查院,青海,西宁,810012 2. 青海省水文地质工程地质勘查院,青海,西宁,810012 3. 青海省第四地质勘查院,青海,西宁,810012 |
| 基金项目： | 中国地质调查局《1:25万治多，杂多幅(I46C004004)区域地质调查》项目 |
| 摘 要： | 在龙木错-双湖-澜沧江缝合带北侧，沿青海省囊谦县尕羊及其以西，新发现皇北西向带状分布的晚二叠世正长花岗岩侵人体。其岩性为中细粒含白云母正长花岗岩，岩石以酸性程度高、富硅、富碱、富铝及非常高的稀土含量为特点，岩石的铝过饱和指数ASI平均值达1．166，CIPW标准矿物中刚玉分子平均为5．08，为典型的高钾钙碱性系列的过铝质花岗岩。其岩石类型相当MPG含白云母过铝质花岗岩类；岩石EREE高达466．55×10^-6～682．80×10^-6，具有强的Eu负异常，δEu平均值为0．06，微量元素含量富不相容元素（LILE），贫高场强元素（HFSE），具有典型的S型花岗岩的特征，与冈底斯碰撞花岗岩特征近一致．构造分析相当于Maniar花岗岩分类中的CCG花岗岩（大陆碰撞花岗岩）。在尕羊正长花岗岩中获得了251．4±0．6Ma的TIMS法锆石U—Pb同位素年龄，其形成时代为晚二叠世，与在乌兰乌拉湖一澜沧江结合带内获得的251．5±2．6Ma和249±49Ma热年代信息一致，反映晚二叠世-早三叠世构造热事件的存在．可能属于晚二叠世-早三叠世乌兰乌拉湖一澜沧江结合带陆一陆碰撞的产物。 |
| 关 键 词： | 唐古拉地区 龙木错-双湖-澜沧江缝合带 晚二叠世 碰撞型 过铝质花岗岩 |
The Assurance of Syncollisional Granite in Tanggula Area During Late Permian Epoch and Its Significance |
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| QI Sheng-sheng,WANG Yi-zhi,HE Shi-hao,SONG Sheng-chun,QI Zheng-ling,WANG Fu-lin.The Assurance of Syncollisional Granite in Tanggula Area During Late Permian Epoch and Its Significance[J].Northwestern Geology,2009,42(3):26-35. | |
| Authors: | QI Sheng-sheng WANG Yi-zhi HE Shi-hao SONG Sheng-chun QI Zheng-ling WANG Fu-lin |
| Institution: | QI Sheng-sheng, WANG Yi-zhi, HE Shi-hao, SONG Sheng-chun, QI Zheng-ling, WANG Fu-lin (1. Qinghai Geological Survey Institute Xining 810012, Qinghai , China ;2. Qinghai Hydrogeology and Engineering Geology Survey Xining 810012, Qinghai, Geological Prospecting Institute ; Xi＇ning 810012, China ; 3. Qinghai fourth Geological Prospecting Institute X i＇ning 810012, Qinghai , China) |
| Abstract: | In northern Qiangtang-Changdu plate of Longmucuo-Shuanghu-Lancangjiang suture zone , the syenitegranite mass of late Permian Epoch is disjointed from the granites of Yanshannia Age. The component of the rocks is characterized by Al2O3〉CaO ＋Na2O A-K2O, with the average value of ASI reaching 1. 166, showing the character of typical peraluminous granite; in addition, the EREE value of the rock is as high as 466.55×10^-6～682.80×10^-6, with the average value of of δEu being 0. 06, showing the character of typical S-type granites. The rock type is equivalent MPG-granite and is interpreted as the syncollisional granite. The zircon U-Pb isotope age is 251. 43-0. 6Ma, indicating that the implacement age is in late Permian Epoch. All these reflect a tectonic-thermal event during late Permian Epoch to Triassic Epoch, which might be the tectonic outcome of continent-continent collision in Wulanlua lake-Lancangjiang suture zone . |
| Keywords: | Tanggula area Longmucuo-Shuanghu-I ancangjiang suture zone Irate Permian Epoch syncollisional peraluminous granite |
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