本文研究鹤壁金伯利岩中的锆石U-Pb年代学和稀土元素结果。阴极发光照片和微量元素结果表明金伯利岩中锆石为岩浆结晶成因。锆石U-Pb年代学结果显示为两组年龄,分别为(2531±22)Ma(MSWD为0.77,n为9)和(1797±34)Ma(MSWD为2.1,n为16)。这两组年龄记录了华北板块克拉通化过程,其中约1.8 Ga的年龄很可能是华北板块克拉通化的最晚年龄。金伯利岩与本区内新生代玄武岩的出露都受中新生代构造体系控制,岩石地球化学研究表明:两者均来自于具有相似的地幔源区,指示鹤壁金伯利岩可能侵位时代为新生代。
The results of U-Pb geochronology and REE research on zircon from kimberlits of Hebie region are studied. Cathodoluminescence images and trace elements show that the zircon was formed by igneous crystallization. Zircon U-Pb geochronology results give two ages,respectively( 2531 ± 22) Ma( MSWD = 0. 77,n =9) and( 1797 ± 34) Ma( MSWD = 2. 1,n = 16) namely that the zircon was formed at two geological stages.These two ages may record the formation and stabilization of North China Craton( NCC),and the younger age may suggest to be the last stage of NCC Cratonization. The occurance of kimberlits and the Cainozoic basalt outcrops were dominated by the neocathaysian structral system faults. The kimberlits and the basalt were all origented from partial melting of asthenosphere. Thusly,it is inferred that the kimberlits may formed at Cainozoic based on the above evidence.