| 大兴安岭中段早白垩世花岗质岩石锆石U-Pb年龄及地球化学特征 |
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| 引用本文： | 陈会军,张彦龙,王清海,杨浩,钱程,陈井胜,秦涛,汪岩,吴新伟,张渝金.大兴安岭中段早白垩世花岗质岩石锆石U-Pb年龄及地球化学特征[J].地质与资源,2015,24(5):433-443. |
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| 作者姓名： | 陈会军 张彦龙 王清海 杨浩 钱程 陈井胜 秦涛 汪岩 吴新伟 张渝金 |
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| 作者单位： | 1. 中国地质调查局 沈阳地质调查中心(沈阳地质矿产研究所), 辽宁 沈阳 110034;2. 吉林大学 地球科学学院, 吉林 长春 130061;3. 吉林大学 东北亚国际地学研究与教学中心, 吉林 长春 130026 |
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| 基金项目： | 中国地质调查局项目“东北地区花岗岩地质编图”（1212011121084）、“东北重大岩浆事件及其成矿作用与构造背景综合研究”（12120114085601）. |
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| 摘 要： | 大兴安岭地区显生宙花岗岩分布广泛,但区内中生代花岗岩的研究相对薄弱.通过对大兴安岭中段扎兰屯以西的毕家店岩体和神山岩体进行年代学和地球化学研究,探讨了本区早白垩世花岗岩的成因及构造背景.其中毕家店岩体主要由正长花岗岩和花岗斑岩组成,神山岩体主要由碱长花岗岩组成.毕家店岩体的锆石U-Pb年龄为136±3 Ma、139.5±0.9 Ma和128.1±0.8 Ma,神山岩体为119.3±0.8 Ma,均形成于早白垩世.地球化学特征上,两岩体均呈现高硅、低钙、富碱、Eu负异常等特征,亏损Nb、Ta,富集Rb、Th和U,属于弱过铝质高钾钙碱性系列,为岩浆演化晚期的高分异I型花岗岩.两岩体具有活动大陆边缘构造属性,结合大兴安岭地区同时期I型、A型花岗岩特征,认为早白垩世花岗质岩石的形成与太平洋板块俯冲背景下的拆沉作用密切相关.
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| 关 键 词： | 早白垩世 锆石U-Pb年龄 花岗质岩石 大兴安岭中段 |
| 收稿时间： | 2014-12-12 |
ZIRCON U-Pb DATING AND GEOCHEMISTRY OF THE EARLY CRETACEOUS GRANITIC ROCKS IN THE MIDDLE SECTION OF DAXINGANLING MOUNTAINS |
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| CHEN Hui-jun,ZHANG Yan-long,WANG Qing-hai,YANG Hao,QIAN Cheng,CHEN Jing-sheng,QIN Tao,WANG Yan,WU Xin-wei,ZHANG Yu-jin.ZIRCON U-Pb DATING AND GEOCHEMISTRY OF THE EARLY CRETACEOUS GRANITIC ROCKS IN THE MIDDLE SECTION OF DAXINGANLING MOUNTAINS[J].Geology and Resources,2015,24(5):433-443. |
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| Authors: | CHEN Hui-jun ZHANG Yan-long WANG Qing-hai YANG Hao QIAN Cheng CHEN Jing-sheng QIN Tao WANG Yan WU Xin-wei ZHANG Yu-jin |
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| Institution: | 1. Shenyang Institute of Geology and Mineral Resources, CGS, Shenyang 110034, China;2. College of Earth Sciences, Jilin University, Changchun 130061, China;3. International Center for Geosciences Research and Education in Northeast Asia, Jilin University, Changchun 130026, China |
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| Abstract: | The Phanerozoic granites are widely distributed in the Daxinganling region, but the research on Mesozoic granites was relatively poor. The paper conducts a geochronological and geochemical study on the Early Cretaceous granites collected from Bijiadian pluton and Shenshan pluton on the west of Zhalantun in the middle section of Daxinganling Mountains, and discusses the petrogenesis and tectonic setting of the granitic rocks. The LA-ICP-MS zircon U-Pb dating indicates that the Bijiadian pluton is mainly composed of syenogranite and granite porphyry, with ages of 136±3 Ma, 139.5±0.9 Ma and 128.1±0.8 Ma, whereas the Shenshan pluton consists of mainly alkali-feldspar granites, with age of 119.3±0.8 Ma, which indicate that both of them were formed in the Early Cretaceous. The two plutons are geochemically characterized by high Si, low Ca, rich Alkali, negative Eu anomalies, enrichment of Rb, Th and U, and depletion of Nb and Ta, belonging to the weakly peraluminous high-K calc-alkaline series and quite similar to highly fractionated I-type granitoids. Combined with the petrological and geochronological features of the coeval granitoids in Daxinganling region, it is proposed that the formation of the Early Cretaceous granitic rocks was closely related to the delamination induced by the subduction of the Pacific plate. |
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| Keywords: | Early Cretaceous Epoch zircon U-Pb dating granitoid the middle section of Daxinganling Mountains |
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