【摘要】 采用U Pb和Pb Pb方法研究了内蒙古白云鄂博赋矿H8白云岩的年代。U Pb体系不能给出等时线 ,因为体系中铀显著过剩 ,显示了铀的近代加入。Pb Pb等时线 ,得到中元古约 15 0 0± 40 0Ma的Pb Pb年龄 ,并经过了约 82 0± 370Ma的后期扰动。白云鄂博赋矿H8白云岩的成岩年代在中元古代 ,在晚元古代或古生代发生了后期扰动。更多还原

【Abstract】 U-Pb and Pb-Pb dating methods have been used to determine the age of H8 dolomite in Bayan Obo Ore Deposit. No U-Pb isochron was obtained. Pb-Pb isochron give Meso-Proterozoic age of about 1 500±400Ma, a disturbance time of about 820±370Ma. However, an obvious U excess was shown and might be caused by recent addition of U. Based on these data, we suggest that H8 dolomite of the Bayan Obo deposit was formed in Meso-Proterozoic era, but underwent a late disturbance during Neo-Proterozoic or Paleozoic era.更多还原