| 内蒙古乌拉山地区沙德盖岩体年代学、地球化学特征及成因探讨 |
| |
| 引用本文： | 侯万荣,聂凤军,胡建民,刘翼飞,肖伟,刘勇,张可.内蒙古乌拉山地区沙德盖岩体年代学、地球化学特征及成因探讨[J].吉林大学学报(地球科学版),2011,41(6):1914-1927. |
| |
| 作者姓名： | 侯万荣 聂凤军 胡建民 刘翼飞 肖伟 刘勇 张可 |
| |
| 作者单位： | 1.中国地质科学院矿产资源研究所,北京100037;
2.中国人民武装警察部队黄金第一总队,哈尔滨150086 |
| |
| 基金项目： | 国家重点自然科学基金项目(41030421); 全国危机矿山接替资源找矿项目(20089948); 中国地质调查局地质调查项目(1212010911029); 中国地质科学院基本业务费项目(K1012) |
| |
| 摘 要： | 沙德盖岩体位于华北克拉通北缘中段、哈达门沟大型金（钼）矿田范围内。首次利用锆石 SHRIMP U-Pb法对其定年，获得15个锆石颗粒206Pb/238U年龄的加权平均值（221.6±2.1） Ma（MSWD=1.6），表明岩体侵位于印支中期。岩石地球化学特征表现为高硅（SiO2质量分数为71.21%～73.67%）、富钾（K2O/Na2O为1.01～1.37）、富碱（K2O+Na2O为8.23%～9.96%）、弱过铝质（Al2O3为13.11%～14.31%），里特曼指数σ=2.43～3.52，钙碱性-碱性;富集轻稀土（LREE/HREE为17.68～14.92，（La/Yb）|N为22.85～16.58）和Eu略亏损（δEu=0.95～0.93）;微量元素亏损Nb、Ta、P、Ti、Sr，富集K、La、Ce、Hf等元素，具有A型花岗岩特征；(87Sr/86Sr)i=0.705 31～0.702 29，(143Nd/144Nd)i=0.511 682～0.511 620，εNd(t)=-13.1～-14.3，具有壳源特点;钕两阶段模式年龄T2DM=2 061～2 160 Ma，在铅构造模式图上样品投点于地幔与下地壳之间。综合分析认为其形成于同碰撞向后碰撞构造体制转换，伸展构造和幔源基性岩浆的底侵导致早期古老基底地壳部分熔融，很可能是形成沙德盖岩体的主要动力机制。华北克拉通北缘印支期构造岩浆活动及成矿作用是普遍存在的。
|
| 关 键 词： | 华北克拉通北缘 沙德盖岩体 地质年代学 地球化学 三叠纪 |
| 收稿时间： | 2011-06-08 |
Geochronology and Geochemistry of Shadegai Granites in Wulashan Area,Inner Mongolia and Its Geological Significance |
| |
| HOU Wan-rong,NIE Feng-jun,HU Jian-min,LIU Yi-fei,XIAO Wei,LIU Yong,ZHANG Ke.Geochronology and Geochemistry of Shadegai Granites in Wulashan Area,Inner Mongolia and Its Geological Significance[J].Journal of Jilin Unviersity:Earth Science Edition,2011,41(6):1914-1927. |
| |
| Authors: | HOU Wan-rong NIE Feng-jun HU Jian-min LIU Yi-fei XIAO Wei LIU Yong ZHANG Ke |
| |
| Institution: | 1.Institute of Mineral Resoures, Chinese Academy of Geological Sciences, Beijing100037,China;
2.The First Gold General Party of Chinese People’s Armed Police Force, Harbin150086, |China |
| |
| Abstract: | The Shadegai granite is located in Hadamengou large gold-molybdemum orefield, in the north margin of North China craton. The SHRIMP U-Pb weighted average age of 15 zircon grains from the Shadegai granites is (221.6±2.1) Ma（MSWD=1.6），which indicates the granite emplaced in the medium Indosinian epoch. Geochemical characteristics show that the granite is characterized by high silicon(SiO2=71.21%Northern margin of North China craton； Shadegai granite； geochronology； geochemistry； Triassic 73.67%), potassium-rich (K2O/Na2O=1.01-1.37), rich alkaline(K2O+Na2O=8.23%-9.96%), weakly peraluminous（Al2O3=13.11%-14.31%）. The Rittmann index (σ) of granite varies from 2.43 to 3.52, which means that the rock samples are calc-alkaline to alkaline. The ∑REE varies from 185.70×10-6 to 96×10-6, the ratios of LREE/HREE and LaN/YbN are 17.68-14.92 and 22.85-16.58, respectively, and δEu is weakly negative anomalies. Trace elements composition exhibit such characteristics of A-type granite, as depletion of Nb, Ta, P, Ti, Sr，and enrichment of K, La, Ce, Hf. The values of (87Sr/86Sr)i is from 0.705 31 to 0.702 29， (143Nd/144Nd)i from 0.511 682 to 0.511 620，and εNd(t) from -13.1 to -14.3, indicating that the magma source of Shadegai granite should have been mainly of crust-derivation. Nd isotope two-stage model ages(T2DM) are 2 061-2 160 Ma. In the tectonic model diagram of lead isotopic compositions, the granite samples are plotted between the mantle and lower crust curves. The comprehensive analysis suggests that the Shadegai granite formed under the tectonic setting of transformation from syn-collision to post-collision. Statistics indicate that the magmatism and mineralization took place extensively in the northern margin of North China craton during the Indosinian epoch. |
| |
| Keywords: | Northern margin of North China craton Shadegai granite geochronology geochemistry Triassic |
| 本文献已被 CNKI 万方数据 等数据库收录！ |
| 点击此处可从《吉林大学学报(地球科学版)》浏览原始摘要信息 |
| 点击此处可从《吉林大学学报(地球科学版)》下载免费的PDF全文 |
|
