【摘要】 通过研究表明,东秦岭官坡超高压变质岩片具有较高的放射性成因铅同位素组成:206Pb/204Pb=18.089～18.772,207Pb/204Pb=15.571～15.631,208Pb/204Pb=38.299～38.829。其铅同位素组成与秦岭岩群及二郎岩坪群一致,而与大别超高压变质带有明显的区别。结合构造分析可以判断,东秦岭超高压变质带与大别超高压变质带是两个不同的构造带,中央造山带内可能至少发育有两条超高压变质带。更多还原

【Abstract】 The spatial relationship between the East Qinling and Dabie-Sulu UHP metamorphic belts has been a controversy. Pb isotopic study indicated that the UHP metamorphic rocks from Guanpo UHP fragment in East Qinling were characterized by highe Pb isotopic compositions with （）²⁰⁶Pb/（）²⁰⁴Pb=18.089¹8.772,（）²⁰⁷Pb/（）²⁰⁴Pb=15.571¹5.631,and （）²⁰⁸Pb/（）²⁰⁴Pb=38.299^38.829.The Pb isotopic compositions of the UHP fragment in East Qinling are different from those in the Dabie UHP metamorphic belt,but consistent with the rocks from the Qinling rock group and Erlangping rock group. On the basis of the Pb isotopic compositionsand the structural analysis,the East Qinling UHP metamorphic belt was different from the Dabie UHP metamorphic belt and they did not belong to a single giant belt. Therefore,it is likely that there are at least two UHP metamorphic belts of different age within the Central Orogenic Belt.更多还原