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| 新疆北山矛头山东早二叠世火山岩喷发活动时代厘定及地球化学特征分析 | |
| 引用本文： | 李煜航,杨兴科 王庆良 崔笃信 季灵运 郝 明.新疆北山矛头山东早二叠世火山岩喷发活动时代厘定及地球化学特征分析[J].中国地质,2012,39(3):683-694. |
| 作者姓名： | 李煜航 杨兴科 王庆良 崔笃信 季灵运 郝 明 |
| 作者单位： | 1. 中国地震局第二监测中心,陕西西安710054;中国地震局地质研究所,北京100029 2. 长安大学,陕西西安,710054 3. 中国地震局第二监测中心,陕西西安,710054 |
| 基金项目： | 新疆北山黑山岭东南1∶50 000区域地质矿产调查项目，国家自然科学基金 |
| 摘 要： | 本文对新疆北山矛头山东一带火山岩野外地质特征、岩石学、岩石地球化学和锆石U-Pb年龄进行了系统研究。该区火山岩岩石组合为玄武岩、玄武安山岩、安山岩和同成分的火山碎屑岩。该套火山岩中锆石SHRIMP U-Pb年龄表明,其形成时代为早二叠世。其岩石地球化学特征显示为一套钙碱性火山岩,富集轻稀土元素,无明显的负铕异常;大离子亲石元素Rb、Th、U相对富集,Ba、Sr略有波动,高场强元素Nb略有亏损、Ta亏损明显。综合分析,笔者认为该套早二叠世的火山岩形成于已经充分收缩的残余海盆环境;此时北山的构造属性更与残余海盆的陆缘火山盆地相似,而不具有裂谷的特征。 |
| 关 键 词： | 新疆北山 早二叠世 地球化学 SHRIMP测年 构造演化 |
Redetermination of the volcanic eruption time and analysis of geochemical characteristics of volcanic rocks in eastern Maotoushan of Beishan area, Xinjiang |
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| LI Yu-hang,YANG Xing-ke,WANG Qing-liang,CUI Du-xin,JI Ling-yun,HAO Ming.Redetermination of the volcanic eruption time and analysis of geochemical characteristics of volcanic rocks in eastern Maotoushan of Beishan area, Xinjiang[J].Chinese Geology,2012,39(3):683-694. | |
| Authors: | LI Yu-hang YANG Xing-ke WANG Qing-liang CUI Du-xin JI Ling-yun HAO Ming |
| Institution: | 1(1.Second Crust Monitoring and Application Center,CEA,Xi’an 710054,Shaanxi,China;2.Institute of Geology,CEA,Beijing 100029,China;3.Chang’an University,Xi’an 710054,Shaanxi,China) |
| Abstract: | The field geological features,petrology,lithogeochemistry and high degree of accuracy isotope chronology of volcanic rocks in eastern Maotoushan of Beishan area,Xinjiang,are discussed in this paper.The rock association of this area is composed of basalt,basaltic andesite,andesite and tuff with the same components.U-Pb isotope SHRIMP dating shows that the eruption time of volcanic rocks should be Lower Permian.The volcanic rocks are of the calc-alkaline series.No obvious REE fractionation and clear negative Eu anomalies are observed,and there exist enrichment of Rb,Th and U,slightly fluctuation of Ba,Sr,and loss of Nb,Ta.An integrated analysis led the authors to believe that the early Permian volcanic rocks were formed in a fully shrunk residual sea basin environment,and the structural attributes at that time were similar to features of the epicontinental volcanic basin of the residual sea basin instead of having the characteristics of the rift. |
| Keywords: | Beishan area in Xinjiang Lower Permian geochemistry SHRIMP dating tectonic evolution |
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