| 北祁连老虎山玄武岩和硅岩的地球化学特征及形成环境 |
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| 引用本文： | 钱青,张旗,孙晓猛,王岳明.北祁连老虎山玄武岩和硅岩的地球化学特征及形成环境[J].地质科学,2001,36(4):444-453. |
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| 作者姓名： | 钱青 张旗 孙晓猛 王岳明 |
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| 作者单位： | 1. 中国科学院地质与地球物理研究所, 北京, 100029;2. 吉林大学地球科学学院, 长春, 130022;3. 甘肃省地质矿产局区域地质调查队, 兰州, 730050 |
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| 摘 要： | 北祁连老虎山地区玄武岩与沉积岩呈互层产出,玄武岩主要为E-MORB,少数为N-MORB;多数样品具Nb负异常,表明很可能形成于弧后盆地环境。玄武岩中的沉积岩夹层主要为浊积岩、硅岩和硅质泥岩,有少量含棘皮类和双壳类化石的层状生物碎屑灰岩。浊积砂岩中含有大量陆源石英碎屑,硅岩具较高的Al2O3Fe2O3比值和较低的MnO/TiO2比值,不具有明显的Ce负异常。上述特征表明老虎山玄武岩及其中的沉积岩夹层形成于弧后盆地中靠近陆缘的环境。
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| 关 键 词： | 北祁连老虎山 玄武岩 硅岩 地球化学 形成环境 |
| 收稿时间： | 2000-07-04 |
| 修稿时间： | 2000年7月4日 |
GEOCHEMICAL FEATURES AND TECTONIC SETTING FOR BASALTS AND CHERTS FROM LAOHUSHAN , NORTH QILIAN |
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| Qian Qing,Zhang Qi,Sun Xiaomeng,Wang Yueming =.GEOCHEMICAL FEATURES AND TECTONIC SETTING FOR BASALTS AND CHERTS FROM LAOHUSHAN , NORTH QILIAN[J].Chinese Journal of Geology,2001,36(4):444-453. |
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| Authors: | Qian Qing Zhang Qi Sun Xiaomeng Wang Yueming = |
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| Institution: | 1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029;2. College of Earth Sciences, Jilin University, Changchun 130022;3. Regional Geological Survey, Bereau of Geology and Mineral Resources of Gansu Province, Lanzhou 730050 |
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| Abstract: | The basalts from Laohushan, north Qilian, are mainly basalts of E MOEB, with very few N MORB. Most of the basalts are depleted in Nb, indicating a back arc tectonic setting. Layers of sediments, including tubiditic conglomerates, sandstones, cherts and occasionally echinodermata and bivalve bearing limestones, are intercalated with the basalts. The sandstones contain lots of continental quartz clasts, and the cherts have high Al 2O 3/Fe 2O 3, low MnO/TiO 2 ratios and very small Ce negative anomaly. Geochemical characteristics of the basalts and cherts, as well as lithofacies of the sediments, indicate that the Laohushan basalts were formed close to the continental margin in a back arc basin. |
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| Keywords: | Laohushan in north Qilian Basalts Cherts Geochemistry Tectonic setting |
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