伊春东风经营所新元古代花岗质片麻岩U-Pb年代学和地球化学特征  

Characteristics of U-Pb chronology and geochemistry of Neoproterozoic granitic gneiss in Dongfengjingyingsuo of Yichun area

作　　者：王少轶[1] 刘宝山 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]黑龙江省地质调查研究总院齐齐哈尔分院,哈尔滨150036

出　　处：《世界地质》2014年第4期780-786,共7页World Geology

基　　金：黑龙江省资源补偿项目(HLJKD2008-10)

摘　　要：张广才岭中段东风经营所一带发现新元古代花岗质片麻岩,岩石具有高硅、富碱和低钙、镁及偏铝质-过铝质特点,稀土元素配分模式中轻稀土元素富集且缓向右倾斜,重稀土元素曲线较为平坦,为具有铕亏损的海鸥型,富集高场强元素Th、Zr、Hf,亏损Ba、Sr、P、Ti、Nb、Ta等大离子亲石元素,微量元素特征指示其形成于大陆地壳的部分熔融。锆石LA--ICP MS U--Pb定年结果表明,岩石加权平均年龄为(850.2±2.0)Ma,形成于新元古代。构造环境显示研究区花岗质片麻岩形成于挤压造山环境,为造山期的深熔产物。新元古代花岗质片麻岩的发现,表明研究区之前存在一古老的微陆块。Neoproterozoic granitic gneiss has been found in Dongfengjingyingsuo of central Zhangguangcai Range with the petrological characteristics of high-SiO2,rich-alkali,low-CaO,low-MgO and peraluminous metaluminous.The REE patterns are riched of LREE and the curve is gentle rightward sloping.The curve of HREE is flatter,showing the seagull shape with Eu negative anomaly.The granitic gneiss is riched in HFSE （Th,Zr,Hf）,and deficited in LILE （Ba,Sr,P,Ti,Nb,Ta,ect）.The characteristics of microelement indicate that the granitic gneiss was formed due to the partial melting of continental crust.The SHRIMP zircon U-Pb age suggests that the average age of the granitic gneiss was （850.2 ± 2.0） Ma,formed in Neoproterozoic.The tectonic environment shows that the granitic gneiss was formed in compressive orogenic environment,which was the product of anatexis magma orogenic period.The discovery of Neoproterozoic granitic gneiss implies that there was an ancient landmasses in the studied area before.

关 键 词：伊春东风经营所 新元古代 花岗质片麻岩 地球化学 挤压造山环境 

分 类 号：P534.3[天文地球—古生物学与地层学] P588.34[天文地球—地质学]