| 大兴安岭温布其地区白音高老组火山岩的形成机制 |
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| 引用本文： | 王阳,徐仲元,刘正宏,李世超,王师捷,杜洋.大兴安岭温布其地区白音高老组火山岩的形成机制[J].世界地质,2017,36(3):714-725. |
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| 作者姓名： | 王阳 徐仲元 刘正宏 李世超 王师捷 杜洋 |
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| 作者单位： | 吉林大学地球科学学院, 长春 130061 |
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| 基金项目： | 国家自然科学基金项目（41340024）与中国地质调查局项目（1212011121085）联合资助. |
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| 摘 要： | 大兴安岭温布其地区白音高老组火山岩主要由流纹质岩屑晶屑凝灰岩和流纹岩等一系列酸性火山岩构成。LA-ICP-MS锆石U-Pb测年结果显示,研究区流纹岩形成于(131±1.5)Ma,为早白垩世;岩石地球化学研究表明,样品具有高硅SiO_2(72.43%~78.64%)、富铝Al2O3(11.48%~14.24%)、富钾K_2O(4.09%~5.05%)和低镁MgO(0.14%~0.34%)的特点;轻重稀土分馏较明显(La/Yb)_N=8.22~13.68],Eu负异常明显(δEu=0.39~0.90);微量元素相对富集大离子亲石元素Rb、Ba、K,亏损高场强元素Nb、P、Ti。~(176)Hf/~(177)Hf比值为0.282 830~0.282 983,εHf(t)为6.02~10.19。研究发现,温布其地区白音高老组火山岩岩浆来源于新元古代亏损地幔增生的年轻基性地壳的部分熔融,形成于伸展的构造环境。
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| 关 键 词： | 大兴安岭 白音高老组 U-Pb测年 温布其地区 |
| 收稿时间： | 2017-01-11 |
| 修稿时间： | 2017-05-20 |
Formation mechanism of Baiyingaolao volcanic rocks in Wenbuqi area of Da Hinggan mountains |
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| WANG Yang,XUN Zhong-yuan,LIU Zheng-hong,LI Shi-chao,WANG Shi-jie,DU Yang.Formation mechanism of Baiyingaolao volcanic rocks in Wenbuqi area of Da Hinggan mountains[J].World Geology,2017,36(3):714-725. |
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| Authors: | WANG Yang XUN Zhong-yuan LIU Zheng-hong LI Shi-chao WANG Shi-jie DU Yang |
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| Institution: | College of Earth Sciences, Jilin University, Changchun 130061, China |
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| Abstract: | The volcanic rocks in Baiyingaolao Formation of Wenbuqi area of Da Hinggan mountains are composed of a series felsic volcanic rocks such as rhyolite and rhyolitic lithic crystal tuff. LA-ICP-MS zircon U-Pb dating results show the rhyolite formed in the Early Cretaceous, aged in (131±1.5)Ma. The geochemical study suggests that the rhyolite is characterized by high SiO2(72.43%~78.64%), Al2O3(11.48%~14.24%), and K2O(4.09%~5.05%), and low MgO(0.14%~0.34%) in contents. Samples are significant in fractionation of HREE and LREE(La/Yb)N=8.22~13.68], with negative Eu anomalies (δEu=0.39~0.90). The trace element are characterized evidently by enrichment of Rb, Ba, K, depletion of Nb,P,Ti. The ratios of 176Hf/177Hf vary in 0.282 830~0.282 983 and the corresponding εHf(t) values are positive ranging from 6.02 to 10.19. Above characteristics indicate that the volcanic rocks derived from the basic lower crust accreted from depleted mantle during Neoproterozoic. Tectonic setting is related to the extensional setting. |
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| Keywords: | Da Hinggan mountains Baiyingaolao Formation U-Pb dating Wenbuqi area |
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