鹤岗北部地区黑龙江岩群的构造属性:来自岩石地球化学、锆石U-Pb定年和Hf同位素的制约  

Tectonic Attribute of Heilongjiang Metamorphic Rocks in the Northern Part of Hegang Area,NE China:Constrains from Geochemistry,Zircon U-Pb Dating and Hf Isotopic Composition

作　　者：李亮[1] 孙景贵[1] 郭维[2] 韩吉龙[1] LI Liang SUN Jinggui GUO Wei HAN Jilong(School of Earth Sciences, Jilin University, Changchun 130061, Jilin, China Geological Institute of North China Geological Exploration Bureau of Tianjin, Tianjin 300170, China)

机构地区：[1]吉林大学地球科学学院,吉林长春130061 [2]天津华北地质勘查局地质研究所,天津300170

出　　处：《大地构造与成矿学》2016年第5期1014-1030,共17页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(41172072和40772052)联合资助

摘　　要：产于鹤岗北部地区的黑龙江岩群是由绿帘绿泥钠长片岩、绿帘蓝闪片岩（下部）和二云母片岩、石榴白云钠长片岩、方解白云钠长片岩、石榴白云钠长石英片岩（上部）等岩系组成。本文通过岩石地球化学、锆石U-Pb年代学和Hf同位素组成研究,厘定下岩组原岩为幔源碱性玄武岩（SiO_2=47.44%~48.38%）及岛弧钙碱性玄武岩（SiO_2=46.84%~49.22%）,有3组锆石U-Pb年龄（526±44 Ma,n=3;249±11 Ma,n=6;207±4 Ma,n=8）;上岩组原岩为海陆交互相碎屑岩（SiO_2=66.70%~93.00%）,有4组锆石U-Pb年龄（484±13 Ma,n=3;429±24 Ma,n=3;277±4 Ma,n=11;262±3 Ma,n=6）。结合锆石的内部结构、Hf同位素和区域构造演化特征,幔源火山喷发和沉积作用发生在277±4 Ma,碰撞造山作用发生在262~249 Ma,构造折返发生在207±4 Ma。这项研究对于深入认识黑龙江岩群性质和构造属性具有重要的意义。The Heilongjiang metamorphic rocks located in the northern part of the Hegang area, NE China, consist of epidote-chlorite-albite schist, epidote-glaucophane schist（the lower group）, and two-mica schist, garnet-muscovite-albite schist, calcite-muscovite-albite schist, garnet-muscovite-quartz schist（the upper group）, etc. Detailed research on geochemistry, zircon U-Pb dating and Hf isotopic composition showed that the protoliths of the lower group are alkali basalt derived from mantle（SiO_2=47.44%- 48.38%）, and island arc calc alkali basalt（SiO_2=46.84%- 49.22%）. The lower group contains three groups of zircon U-Pb age（526±44 Ma, n=3; 249±11 Ma, n=6; 207±4 Ma, n=8）, whereas the protolith of the upper group is alternative continent-marine facies clastic rock（SiO_2=66.70%- 93.00%）, and contains four groups of detrital zircon U-Pb age（484±13 Ma, n=3; 429±24 Ma, n=3; 277±4 Ma, n=11; 262±3 Ma, n=6）. Combined with zircon internal texture, Hf isotopic composition and regional tectonic evolution features, we suggest that the volcanic eruption and sedimentation occurred at 277±4 Ma, and collision orogeny was during 262 Ma to 249 Ma. Tectonic exhumation occurred at 207±4 Ma. The research is significant to identify the nature and tectonic affinity of Heilongjiang metamorphic rocks.

关 键 词：黑龙江岩群 岩石地球化学 锆石U-PB定年 HF同位素 形成环境 构造属性 

分 类 号：P595[天文地球—地球化学] P597[天文地球—地质学]