【摘要】 为查明出露于黑龙江多宝山地区大岔子正长花岗岩体的时代和形成的地质背景,对其进行了锆石SHRIMP U-Pb同位素地质年代学研究.结果显示该锆石具有明显环带结构,Th/U比值为0.41~0.99,是典型的岩浆型锆石.大岔子正长花岗岩锆石共分析了11个测点,206Pb/238U加权平均年龄为345±3 Ma(n=11,SMWD=0.99).该年龄代表了正长花岗岩的结晶年龄,表明正长花岗岩形成时代为早石炭世.对正长花岗岩的主量元素及微量元素的分析表明,该花岗岩属于富钾钙碱性花岗岩类,成因类型属于A型花岗岩.更多还原

【Abstract】 The geochronology with zircon SHRIMP U-Pb isotope of the Dachazi syenogranite,cropped in Duobaoshan area,Heilongjiang Province,is studied to find out its age and geological background.The result suggests that the zircon has significant zonal structure,with Th/U ratio of 0.41-0.99,which is a typical granitic magma-type zircon.Zircons in the syenogranite from 11 observation points are analyzed,obtaining the weighted average 206Pb/235U age of 345±3 Ma(n = 11,SMWD = 0.99),which represents the crystallizing age of the syenogranite,showing the formation age of Early Carboniferous.The analysis on the major elements and geochemistry shows that the syenogranite belongs to high potassium calc-alkaline series,genetically as A-type granite.更多还原