| 张广才岭五道岭组火山岩的锆石U——Pb 年代学及地球化学特征 |
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| 引用本文： | 于倩,葛文春,杨浩,邢德和,张彦龙.张广才岭五道岭组火山岩的锆石U——Pb 年代学及地球化学特征[J].世界地质,2013,32(4):707-716. |
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| 作者姓名： | 于倩 葛文春 杨浩 邢德和 张彦龙 |
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| 作者单位： | 1. 吉林大学地球科学学院，长春130061; 2. 沈阳地质调查中心，沈阳110034 |
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| 摘 要： | 对张广才岭五道岭组火山岩进行锆石U--Pb LA--ICP--MS 年代学和岩石地球化学研究，以确定该组火山岩形成的时代和构造背景。选取样品中的锆石均呈自形--半自形晶，具有清晰的振荡生长环带和较高的Th /U 比值( 0. 52 ～ 2. 28) ，暗示其岩浆成因。测年结果显示，五道岭组火山岩形成于289 ± 3 Ma，是早二叠世岩浆活动的产物。火山岩的岩石组合为玄武岩--流纹岩，显示双峰式火山岩的特点，属于高钾钙碱性--钾玄岩系列，玄武岩具有富集Ｒb、K 等大离子亲石元素( LILE) ，亏损Nb、Ta 等高场强元素( HFSE) 的特征; 流纹岩呈负铕异常，富集Ｒb、Th、U 和K 等大离子亲石元素( LILE) ，亏损Nb、Ta 和Ti 等高场强元素( HFSE) 及Sr、P 元素，并显示A 型流纹岩的特点。结合该时期区域构造演化史，火山岩地球化学特征揭示了五道岭组火山岩的形成与岛弧环境下的局部伸展作用有关，这种构造背景是古亚洲洋板块俯冲于松嫩-张广才岭-佳木斯陆块之下造成的。
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| 关 键 词： | 张广才岭 五道岭组 火山岩 锆石U--Pb 年龄 地球化学 构造背景 |
Zircon U-Pb chronology and geochemical characteristics of volcanic rocks from Wudaoling Formation in Zhangguangcai Range |
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| YU Qian,GE Wen-chun,YANG Hao,XING De-he,ZHANG Yan-long.Zircon U-Pb chronology and geochemical characteristics of volcanic rocks from Wudaoling Formation in Zhangguangcai Range[J].World Geology,2013,32(4):707-716. |
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| Authors: | YU Qian GE Wen-chun YANG Hao XING De-he ZHANG Yan-long |
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| Institution: | 1. College of Earth Sciences，Jilin University，Changchun 130061，China; 2. Shenyang Institute of Geology and Mineral Ｒesource，Shenyang 110034，China |
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| Abstract: | The authors present Formation in Zhangguangcai Range geochronological and geochemical data for the volcanic rocks from Wudaoling in order to constrain their chronology and tectonic setting. Zircons from a representative volcanic rocks are euhedral -subhedral in shape and display fine-scale oscillatory zoning in CL images as well as high Th/U ratios （0. 52 - 2.28 ）, implying their magmatic origin. Zircon U-Pb dating results indicate that the volcanic rocks formed in Early Permian （289 ±3 Ma）. The rock assemblages of Wudaoling Formation are composed mainly of basalts and rhyolites, displaying typical characteristics of bimodal volcanism and belonging chemically high-K calc - alkaline to shoshonite series. The basahs are characterized by a strong enrichment in large ion lithophile elements （LILE） such as Rb, and K, a depletion in high field strength elements （HFSE） such as Nb, and Ta. On the other hand, the rhyolites show a strong enrichment in Rb, Th, U, and K, a depletion in Nb, Ta, and Ti, as well as significant negative Sr, P, and Eu anomalies, and chemically similar to the A-type rhyolite.Combined with the ing Formation were could be related to musi massif. regional tectonic evolution, these geochemical features suggest the volcanic rocks from Wudaol- formed in a local extensional environment, similar to that within an island arc setting which the subduction of the Paleo-Asian oceanic plate beneath the Songnen-Zhangguangcai Range-Jia musi massif. |
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| Keywords: | Zhangguangcai Range Wudaoling Formation volcanic rocks zircon U-Pb chronolggy geochemistry tectonic setting |
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