| 摘要: |
| 冀北承德盆地中生代侏罗纪地层序列较齐全,但作为关键层位之一的九龙山组一直缺乏高精度年代学的约束。笔者首次对九龙山组凝灰岩夹层进行了LA-ICP-MS锆石U-Pb高精度定年,获得凝灰岩中岩浆锆石206Pb/238U加权平均年龄164.1±1.3 Ma。综合研究及对比表明,九龙山组的时限为158~164Ma,属中侏罗世晚期至晚侏罗世早期,对应于国际地层表的牛津期至卡洛维期,其沉积时间相对短暂。在此基础上,更新了研究区侏罗系年代地层柱状图,该认识对于深入研究燕山地区中生代侏罗纪地层格架及构造岩浆演化过程具有重要意义。 |
| 关键词: 凝灰岩 九龙山组 LA-ICP-MS锆石U-Pb定年 承德盆地 |
| DOI： |
| 附件 |
| 投稿时间：2013-11-29修订日期：2014-05-23 |
| 基金项目:中国地质调查局地质大调查项目《晋冀成矿带地质矿产调查》(1212011220486) |
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| The tuffs from the Jiulongshan Formation in the Chengde Basin, northern Hebei: LA-ICP-MS zircon U-Pb age dating and its geological implications |
| ZHANG Yun-qiang, CHEN Hai-yan, WEI Wen-tong, CHEN Chao, LIU Ying-long, ZHANG Liguo, ZHU Zhi-pan |
| (Hebei Institute of Regional Geological Survey and Mineral Resources, Langfang 065000, Hebei, China) |
| Abstract: |
| The first LA-ICP-MS zircon U-Pb age dating is measured for the tuffs from the Jiulongshan Formation in the Chengde Basin, northern Hebei, and gives a weighted average value of 206Pb/238U ages of 164.1±1.3 Ma. The authors contend from the above result and 1:50 000 geological surveying of the Xinzhangzi and Chengde Sheets that the Jiulongshan Formation should be dated at 158-164 Ma, i. e., the late Middle Jurassic to the early Late Jurassic, or the Oxfordian-Callovian in the international stratigraphic chart. The result of research may provide an important evidence for the division of the Jurassic stratigraphic sequences, construction of chronostratigraphic framework, and further study of Mesozoic magmatic-tectonic evolution in the Yanshan area, northern China. |
| Key words: tuff Jiulongshan Formation LA-ICP-MS zircon U-Pb age dating Chengde Basin |
