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侵入冀东马兰峪复背斜的前寒武岩层中的花岗岩体与区内金矿床有密切的空间关系 ,但成岩时代有争议 ,与金矿床的成因关系不明。本文采用SHRIMP定年方法对含有金矿床的峪耳岩和牛心山岩体进行了锆石U Pb年龄测定 ,获峪耳崖岩体灰白色花岗岩的2 0 6Pb 2 3 8U年龄 175± 1Ma ,肉红色花岗岩的年龄为 174± 3Ma ;牛心山花岗岩的年龄为 172± 2Ma。这 3个年龄在误差范围内可看成是同时代的产物 ,属中生代燕山期。这组年龄限定了金矿化年龄的下限 ,表明金矿化发生在中生代燕山中期后 ,但并不能精确厘定金矿化的年龄 ,因为花岗岩侵入后 ,金矿化之前 ,还有脉岩侵入 ,金矿化与花岗岩本身并无直接的成因关系。
The intrusive granodiorites in the Precambrian strata of the MalanYu complex anticline in the eastern part of Hebei Province have close spatial relationship with the gold deposits in the region. However, the diagenetic age is controversial and the origin of the gold deposits is unknown. In this paper, the zircon U Pb ages of the Yu’er and Niunshan plutons containing gold deposits were determined by the SHRIMP dating method. The age of 206 Ma Pb 2 38 U ages of the granite from the Yu’erya pluton was 175 ± 1Ma and the flesh-red granite Of the age of 174 ± 3Ma; Niu Xinshan granite age of 172 ± 2Ma. These three age errors can be seen as the product of the same period, is a Mesozoic Yanshan period. This group of ages defines the lower limit of the gold mineralization age, indicating that gold mineralization occurred after the mid-Yanshanian Mesozoic, but the age of gold mineralization could not be precisely determined because, prior to gold mineralization, vein invasion occurred after granite intrusion, There is no direct genetic relationship between gold mineralization and granite itself.