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| 北祁连东段红土堡基性火山岩锆石LA -IC P-MS U-Pb年代学及其地质意义 | |
| 引用本文： | 何世平,王洪亮,徐学义,张宏飞,任光明.北祁连东段红土堡基性火山岩锆石LA -IC P-MS U-Pb年代学及其地质意义[J].地球科学进展,2007,22(2):143-151. |
| 作者姓名： | 何世平 王洪亮 徐学义 张宏飞 任光明 |
| 作者单位： | 1. 西安地质矿产研究所,陕西,西安,710054;中国地质大学地球科学学院,湖北,武汉,430074 2. 西安地质矿产研究所,陕西,西安,710054 3. 中国地质大学地球科学学院,湖北,武汉,430074 |
| 基金项目： | 中国地质调查局地质调查项目 |
| 摘 要： | 为精确限定红土堡基性火山岩的形成时代，结合阴极发光分析，分别对北祁连东段红土堡枕状玄武岩和辉绿岩墙进行了LA - ICP - MS 单颗粒锆石微区U - Pb 同位素测年。红土堡枕状玄武岩获得（443.4 ±1.7 ）Ma 和（1 782 ±34 ）Ma 两组年龄值；同时，获得红土堡基性火山岩中辉绿岩墙的年龄为（385.7 ±7.9 ）Ma，并含有（1 697 ±6 ） ～（2 692 ±4 ）Ma 的捕晶锆石年龄信息。认为红土堡基性火山岩的形成时代为晚奥陶世，与其北的陈家河中酸性火山岩的形成时代大体一致，推断红土堡基性火山岩的原始岩浆不同程度遭受了陇山岩群的混染。这一新资料，对进一步研究北祁连造山带东段大地构造格局、构造演化以及北秦岭—北祁连衔接关系具有重要意义。 |
| 关 键 词： | 基性火山岩 辉绿岩墙 锆石U - Pb 年代学 红土堡 北祁连东段 |
| 文章编号： | 1001-8166（2007）02-0143-09 |
| 修稿时间： | 2006-11-06 |
A LA - IC P - M S U - Pb Chronolo gic al Stu dy of Zir co ns from Hongtu bu Basic Volc anic Rocks and Its Geolo gical Significance in the East Segment of North Qilian Orogenic Belt |
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| HE Shi-ping,WANG Hong-liang,XU Xue-yi,ZHANG Hong-fei,REN Guang-ming.A LA - IC P - M S U - Pb Chronolo gic al Stu dy of Zir co ns from Hongtu bu Basic Volc anic Rocks and Its Geolo gical Significance in the East Segment of North Qilian Orogenic Belt[J].Advance in Earth Sciences,2007,22(2):143-151. | |
| Authors: | HE Shi-ping WANG Hong-liang XU Xue-yi ZHANG Hong-fei REN Guang-ming |
| Institution: | 1．Xi’an Institute of Geology and Mineral Resources, CGS, Xi’an 710054,China；2．School of Earth Sciences, China University of Geoscience, Wuhan 430074,China |
| Abstract: | In order to lim it accurate form ation tim e of Ho ngtubu basic volcanic rocks in the east segment of North Qilian orogenic belt ， LA - ICP - MS U - Pb isotope dating technique ， combined with cathodolum inescence im age（CL） study ， was separately used to determ ine the zircons from pillow basalt and diabase dyke. Two main populations of zircons from Hongtubu pillow basalt w ere obtained ， giving an average 206 Pb / 238 U ages of （443.4 ±1 .7 ）Ma and an upper- intercept 206 Pb / 238 U -207 Pb / 235 U age of （1 782 ±34 ） Ma. Meanw hile ， LA - ICP - MS U - Pb analyses for zircon grains from the diabase dyke w ithin Hon gtubu basalts yielded a m ean age of （385.7 ±7 .9 ）Ma， and a group of apparent 207 Pb / 206 Pb ages from （1 697 ±6 ）Ma to （2 692 ±4 ） Ma. W ith the relevantdata synthesized ， Hongtubu basic volcanic rocks w ere considered to form in the Late Ordovician ， corresponding to the age of Chen jiahe medium - acid volcanic rocks which locate in the north of Hongtubu basic volcanic rocks. It was deduce d that prim itive m ag- m a of the basic volanic rocks was contam inated in different degree by Longshan rock group. T hese new data have important significance for further research on the tectonic form work in the east segment of the north Qilian orogenic belt ， its tectonic evolution ， and the connected relation of North Qilian and North Qinling orogenic belt. |
| Keywords: | Basic volcanic rock Diabase dyke Zircon U-Pb chronology Hongtubu The east segment of north Qilian |
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