【摘要】 本文采用LA-MC-ICP-MS方法获得班韦乌卢地块卡萨马北部正长花岗岩中锆石的²⁰⁷Pb/²⁰⁶Pb年龄加权平均值为2 011±20 Ma（N=17,MSWD=3.9）,表明班韦乌卢地块基底中正长花岗岩主要形成于古元古代且可能与古元古代乌本迪构造带的活动有关。岩石中锆石Lu-Hf同位素的T_DM2年龄变化范围为3 018～2 184 Ma,明显大于锆石的形成年龄;具有不均一的ε_Hf（t）值（-7.1～6.6）显示形成正长花岗岩的原始岩浆具有壳幔混合的特点,可能为新太古代-古元古代地壳与幔源混染物质。更多还原

【Abstract】 The zircon LA-MC-ICP-MS U-Pb dating results of the syenogranite show that their weighted ²⁰⁷Pb/²⁰⁶U age is 2011 ± 20 Ma（N=17, MSWD=3.9）, indicating that the intrusion of the syenogranite intruded in the Palaeoproterozoic have a good relation with the Paleoproterozoic Ubendian Belt. The range of T_DM2 ages from zircons Lu-Hf isotopic Compositions varies from 3 018 Ma to 2 184 Ma, which is obviously greater than the age of zircon weighted ²⁰⁷Pb/²⁰⁶U age. Zircon variable ε_Hf（t） values（from-7.1 to 6.6）show that the origin of the syenogranite was a mixture of Neoarchean-Paleoproterozoic crust-mantle.更多还原