SHRIMP U-Pb zircon age of magmatic rock in Paishanlou gold mine district, Fuxin, Liaoning Province, China
LUO Zhen kuan1, MIAO Lai cheng1,2, GUAN Kang1, QIU You shou1, Y. M. QIU3, N. J. McNaughton3, D. I. Groves3(1. Tianjin Geological Academy, Tianjin 300061, China; 2. Instutite of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029, China; 3
Paishanlou gold deposit is situated in Fuxin area at the margin of the North China craton occurring in Proterozoic meta volcanic clastic rock of Waziyu Formation. Ore bodies in layeroid and lenticular forms are strictly controlled by ductile shear zone and hosted in biotite anorthose gneissic mylonite and felsic mylonite, generally in altered mylonite. Pyrite, minor poly metal sulfides and native gold are the main ore minerals accounting for about 1%～3%of the ore. Sericite, biotite, feldspar are main gangue minerals. YanshanianDashitougou biotite granite batholith is widely outcropped in the north of the mine district and various dykes are developed in the mine district. The dykes are the deformed pre ore diorite porphyrite and granite porphyry, the post orerhyolite porphyry, diabase and lamprophyre. SHRIMP technique is applied to determine U Pb age of the deformed pre ore diorite porphyrite and granite porphyry dykes and the post ore diorite porphyrite dykes and the Dashitougou granitebatholith. Measurement on the zircon from the deformed pre ore diorite porphyrite shows 206Pb/ 238Pb age of (126±2) Ma and (124±1) Ma from the deformed pre ore granite porphyry; (125±1) Ma and (124±1) Ma from the post ore diorite porphyrite and Dashitougou batholith respectively. Therefore, the four kinds of magmatic rocks may be formed contemporaneously in the permitted measurementlimit of error. The Ar Ar age measured on biotite from the ore before is (124.4±0.4) Ma. The close coincidence indicates that Paishanlou gold deposit was formed in Yanshanian Period and the contemporaneous magmatic activities provided heat dynamics and thermal fluid. The gold deposit, together with the other Yanshanian gold deposits, such as those in Jiaodong (Shandong Province), Beipiao (west Liaoning Province) Chifeng (Inner Mongolia), Zhangjiakou (Hebei Province) and Wulashan (Inner Monglia) which are all located in Precambrian rocks and controlled by ductile shear zone imply that Yanshanian Period is major Au ore forming epoch in East China.
【Fund】： 中国和澳大利亚经济技术合作研究基金;; 国家攀登预选项目(95-预-25)
【CateGory Index】： P597
【CateGory Index】： P597