【摘要】 西南天山南缘震旦纪后碰撞过铝花岗岩同位素U-Pb年龄成果为(601.5±3.4)Ma和(677.3±3.8)Ma.岩石高硅富碱,A/CNK值平均1.02,C-norm≤1.79,属高钾钙碱性系列过铝质花岗岩类.岩石ΣREE普遍较低,呈明显负铕异常,分布曲线为显著的"V"字型,轻重稀土分馏程度较弱.与洋脊花岗岩相比,明显富集Rb,Th,相对富集Ce,Sm,强亏损Ba,相对亏损Zr,Ta,Nb亏损不明显.地球化学特征表明,该花岗岩形成于后碰撞环境.结合区域资料,认为震旦纪后碰撞过铝花岗岩形成于塔里木运动后碰撞期,是塔里木微板块和伊犁微板块边缘发生相对水平剪切运动,岩石圈源岩熔融.塔里木运动下限可能延伸到晚震旦纪早期.更多还原

【Abstract】 The U-Pb isotope ages of the Sinian post-collision peraluminous granite around shouth margin of the southwest Tian Shan are(601.3±3.4) Ma and(677.3±3.8) Ma,separately,The rocks are high silicon and rich alkali,the granite mean ratio of A/CNK is 1.02,its C-norm is ≤1.79.So,the granite belongs to high K and Ca alkali granite.∑REE of peraluminous granite is usally low,with obvious Eunegative anomaly,and distribution plot of the rock is marked V model,fractionation of LREE and HREE of the rock is weak.Compared wth ocean ridge granite,it is charactered by high rich Rb&Th,relatively rich Ce and Sm,strong deficit Ba,relatively loss Zr&Ta,and normal Nb.the geochemical charactors of the granite described as above indicate the rock formated in post-collision period.Intergrated with regional data,it came into being of remelt of lithosphere during horizonetle strike-slip movemenet betweem the Tarim and Yili microplates and the lower-limit of Tarim movement may extend to as old as early stage of late Sinian.更多还原