【作者】 王阳；

【导师】 徐仲元；

【作者基本信息】 吉林大学 ， 构造地质学， 2018， 硕士

【摘要】 本文选取克一河地区大面积满克头鄂博组火山岩为研究对象,通过对前人研究资料的总结整理和野外的实地调查,对研究区内满克头鄂博组火山岩进行了详细的研究,确定了满克头鄂博组火山岩的岩石组合类型、形成时代以及分析了地球化学特征,探讨其岩石成因和构造背景,为大兴安岭北段晚侏罗-早白垩世火山岩活动和地球动力学背景提供新的依据。满克头鄂博组火山岩主要为灰色、灰白色的流纹岩、流纹质岩屑晶屑凝灰岩、英安质凝灰岩。两件样品的锆石LA-ICP-MS U-Pb测年结果分别为137.1±5.1Ma和143.0±0.69Ma,形成于早白垩世早期。在岩石地球化学特征上,具有高硅（SiO₂为70.03%⁷6.46%）、富碱（K₂O+Na₂O为8.10%⁹.52%）,贫钙（CaO为0.03%⁰.95%）、镁（MgO为0.07%⁰.67%）,为高钾钙碱性过铝质岩石。球粒陨石标准化稀土元素分配曲线呈右倾,几乎所有样品呈现Eu的负异常。稀土总量为（∑REE）为96×10^-6231×10^-6,平均值为184×10^-6;轻重稀土元素分馏系数（La/Yb）_N=8.27²1.11,平均值为14.12,轻重稀土明显分馏。该火山岩富集Rb、U、K等大离子亲石元素,相对亏损Nb、Ti、P、Ta等高场强元素。表明研究区满克头鄂博组火山岩源于浅部地壳物质的部分熔融。通过对以往研究资料的整理,与以上数据对比分析,认为研究区满克头鄂博组火山岩在蒙古-鄂霍茨克洋闭合后的造山伸展环境下形成的。更多还原

【Abstract】 This thesis studies the well-developed Manketouebo Formation volcanic rocks of Keyihe area in the major ridge of the north section of Da Hinggan Moutains.Through the summarization of previous research data and field investigations in the field,the rock assemblage,distribution rules and geochemistry of Manketouebo Formation volcanic rocks will be described,and the nature of magma source,petrogenesis and tectonic settings will be discussed in this paper,which will provide new information to researches of the volcanism and tectonic evolution history in Late Jurassic to Early Cretaceous in northern Da Hinggan Moutains.Manketouebo Formation volcanic rocks,which are composed of rhyolite,rhyolite lava,tuff lava.The results of LA-ICP-MS ziron U-Pb dating are 137.1±5.1Ma and143.0±0.69Ma,revealing that Manketouebo Formation volcanic rocks are mainly formed in Early Cretaceous.The volcanic rocks contain high silica（SiO₂=70.03%⁷6.46%）and total alkali（K₂O+Na₂O=8.10%⁹.52%）concentrations,and low concentrations of CaO（0.03%⁰.95%）and MgO（0.07%⁰.67%）.the samples belong to high-K calc-alkaline peraluminous rock.The chondrite-normalized REE paterns indicate that the Mnaketouebo Formation volcanic rocks are enriched in light rare earth elements and almost all strong negative Eu anomaly.ΣREE=96×10^-6231×10^-6,the average value is 184×10^-6,and the value of（La/Yb）_N ranges from 8.27 to 21.11.they are enriched in large ion lithophile elements（LILEs;e.g.,Rb,Th,K）and depleted in high field strength elements（HFSEs;e.g.,Nb,Ti,P,Ta）.The study shows that the volcanic rocks in the Manketouebo formation are partially melted of the shallow crust.Through collation of past research data and comparison and analysis with the above data,it is concluded that Manketouebo Formation volcanic rocks were formed by the effect of the extensional environment caused by the closure of Mongolia-Okhotsk.更多还原