马文,丁玉进,李社宏,张志青,胡兰基,李五福,刘世宝,马延景.祁漫塔格中部元古代高钾(变质)侵入岩体的发现及其地质意义[J].西北地质,2013,46(1):32-39
祁漫塔格中部元古代高钾(变质)侵入岩体的发现及其地质意义
The Discovery and Geological Significance of Proterozoic IntrusiveRock with High-K in the Central of Qimantage Area
  
DOI:
中文关键词:  祁漫塔格;东昆仑;元古宙;高钾 (变质)侵入岩体;地球化学
英文关键词:Qimantage; East Kunlun;Proterozoic;intrusive rock bodies with high-K;geochem-istry
基金项目:
作者单位
马文 青海省地质调查局,青海 西宁810001 
丁玉进 青海省地质调查院,青海 西宁810012 
李社宏 中国科学院广州地球化学研究所,广东 广州510640 
张志青 青海省地质调查院,青海 西宁810012 
胡兰基 青海省岩矿测试应用研究所,西宁810008 
李五福 青海省地质调查院,青海 西宁810012 
刘世宝 青海省地质调查局,青海 西宁810001 
马延景 青海省地质调查局,青海 西宁810001 
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中文摘要:
      通过1∶5万矿产远景调查在祁漫塔格中部圈定出5个大小不等的元古代中酸性高钾 (变质)侵入岩体,岩性为灰- 浅肉红色眼球状二长片麻岩,分布在角闪岩相的火山-沉积岩系中,原岩恢复为二长花岗岩类。锆石U-Pb表面年龄加权平均值为832±12 Ma,是区内已知最早一期中酸性岩浆侵入活动的产物。岩石具高K2O(4.92~5.76×102),贫FeO、MgO、CaO的特点。岩石为高钾钙碱性S型高演化的花岗岩,形成地壳厚度约34.7km,反映同碰撞挤压构造背景。研究表明Rodinia大陆在东昆仑地区830 Ma左右碰撞闭合,此后到早古生代中期,中酸性岩浆活动进入了一个相对不活动的时间段,为Rodinia解体时期,也是板块从低纬度向中高纬度漂移的时期。这一发现对认识东昆仑早古生代构造演化具有重要意义。
英文摘要:
      Five metamorphic intermediate-acid intrusive rock bodies in Proterozoic have been identified in the central Qimantage by the 1∶50000 mineral prospect survey. The intermediate-acid intrusive rock bodies located in amphibolite facies the volcanic-sedimentary rocks are gray-pale flesh red two-feldspar gneiss with eye-shaped. The two-feldspar granites are their original rocks. Zircon U-Pb age is of 832±12 Ma on average, which are known the oldest intermediate-acid intrusive magma products. Geochemistry of rocks is as follows:high K2O(4.92—5.76 ×102), poor FeO, MgO, and CaO. Rocks with high-K are calc-alkaline S-type high-evolution granites that were formed about 34.7 km in crustal thickness. Tectonic setting is shown sys-collision by R1-R2 discriminant diagrams. Rodinia continent closed at about 830 Ma in the East Kunlun. Intermediate-acid magma action reproduced in early Paleozoic. In this process Rodinia breakup and plates in low latitudes moved to high-latitude.The discovery is important to know the structure evolution of early Paleozoic in East Kunlun.
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