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| 松辽盆地徐家围子营城组流纹岩地球化学特征及构造指示意义 | |
| 引用本文： | 孟凡超,刘嘉麒,李明,刘晓,印长海,陆加敏,崔岩.松辽盆地徐家围子营城组流纹岩地球化学特征及构造指示意义[J].岩石学报,2010,26(1):227-241. |
| 作者姓名： | 孟凡超 刘嘉麒 李明 刘晓 印长海 陆加敏 崔岩 |
| 作者单位： | 1. 中国科学院地质与地球物理研究所,北京,100029 2. 中国石油勘探开发研究院,北京,100083 3. 大庆油出勘探开发研究院,大庆,163712 4. 胜利油田地质科学研究院,东营,257015 |
| 基金项目： | 国家“973”项目(2009CB219301)和国家自然科学基金项目(40773023)联合资助 |
| 摘 要： | 松辽盆地徐家围子营城组发育一套以流纹岩为主的中酸性火山岩。岩石薄片观察和主量、微量元素研究发现,后期热液蚀变、区域埋深及低温水合作用对流纹岩的Si、K、Rb等元素含量产生一定影响; 流纹岩明显富集Rb、Th、U、Pb等强不相容元素,Ba、Sr、Ti、Eu、P 负异常,暗示其经历了斜长石、磷灰石和钛铁矿分离结晶作用。流纹岩的(87Sr/86Sr)i(0.705265 ~ 0.711895)值变化范围较大,大多数εNd(t)为正值(1.83 ~ 3.38),Pb同位素比值相对集中,(206Pb/204Pb)i=18.09～18.32,(207Pb/204Pb)i=15.50 ~ 15.54,(208Pb/204Pb)i=37.80 ~ 38.10。研究表明,岩石的源区为大比例年轻成分与少量古老地壳的混合部分熔融,其演化过程中经历了不同程度的地壳混染。松辽盆地早白垩世火山岩为板内伸展环境喷发的产物,可能与太平洋板块俯冲导致的中国东部岩石圈减薄、软流圈上涌密切相关。 |
| 关 键 词： | 松辽盆地 营城组 流纹岩 地球化学 构造意义 |
| 收稿时间： | 3/1/2009 12:00:00 AM |
| 修稿时间： | 2009/10/10 0:00:00 |
Geochemistry and tectonic implications of rhyolites from Yingcheng Formation in Xujiaweizi, Songliao Basin |
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| Meng FC,Liu JQ,Li M,Liu X,Yin CH,Lu JM and Cui Y.Geochemistry and tectonic implications of rhyolites from Yingcheng Formation in Xujiaweizi, Songliao Basin[J].Acta Petrologica Sinica,2010,26(1):227-241. | |
| Authors: | Meng FC Liu JQ Li M Liu X Yin CH Lu JM and Cui Y |
| Institution: | Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Research Institute of Petroleum Exploration and Development, Beijing 100083, China;Research Institute of Petroleum Exploration and Development, Beijing 100083, China;Research Institute of Petroleum Exploration and Development, Daqing Oil Field, Daqing 163712, China;Research Institute of Petroleum Exploration and Development, Daqing Oil Field, Daqing 163712, China;Research Institute of Geological Sciences, Shengli Oil Field, Dongying 257015, China |
| Abstract: | The intermediate-felsic rocks, mainly rhyolites, are widely distributed in Yingcheng Formation in Xujiaweizi, Songliao Basin. Petrological, major and trace elements geochemistry studies exhibit that the content of many elements (e. g. St, K, Rb) of the rhyolites is a little influenced by burial and regional metamorphism, low-temperature hydration and hydrothermal alteration. The rhyolites are prominently enriched strongly incompatible elements such as Rb, Th, U, Pb, and have apparently negative Ba, Sr, Ti, Eu, P anomalies, which indicate the rocks were produced by fractional crystallization of plagioclase, apatite and ilmenite. The rhyolites have high and wide initial ~(87)Sr/~(86)Sr (0.705265～711895) ratios. Most ε_(Nd) (t) values of the rhyolites are all positive and have a narrow range (1.83～3.38), but they have an analogical radiogenic Pb ((~(206)Pb/~(204)Pb)_i = 18.09～18.32, (~(207)Pb/~(204)Pb)~i = 15.50～15.54, (~(208)Pb/~(204)pb)_i =37.80～38.10). The features of isotopic data indicate that the primary magmas were derived originated from a mixed source by juvenile component and ancient crust, but contaminated by the crust in different level during evolution. The rhyolites may erupt in extensional setting within plate in the Early Cretaceous, and were probably associated with the lithospherie thinning and asthenospheric mantle upwelling by subduction of the Pacific plate beneath eastern China. |
| Keywords: | Songliao Basin Yingcheng Formation Rhyolite Geochemistry Tectonic significance |
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