摘要
金顶铅锌矿床的成矿作用发生在中_新生代沉积地层当中 ,且矿区内没有明显出露岩浆岩 ,矿体为板状 ,产在古新统云龙组和下白垩统景星组的陆相碎屑岩中 ,但成矿并不受岩相地层控制 ,而受断裂和穹隆构造控制。铅同位素数据指示成矿金属主要来自地幔。硫同位素具有δ3 4 S黄铁矿 >δ3 4 S闪锌矿 >δ3 4 S方铅矿 的趋势 ,硫主要来自地壳。闪锌矿及有关脉石矿物 (石英、天青石、方解石和硬石膏 )的流体包裹体研究表明 ,均一温度主要在 110～ 15 0℃ ,盐度w(NaCleq) 5 .0 9%～ 19.6 3% ,成矿压力 32 .5～ 2 2 .6MPa ,所对应的成矿深度 0 .9～ 1.5km。
Located in Lanping County, Yunnan Province, the Jinding Pb_Zn deposit is the largest polymetallic deposit in China. The orebodies are hosted in Mesozoic_Cenozoic terrestrial clastic rocks. No igneous rocks have ever been found in the orefield. The deposit has some unique features, which can distinguish it from such sedimentary rock_hosted deposits as MVT_type and Sedex type Pb_Zn deposits. The tabular orebodies (with some veins) are hosted in the Eocene Yunlong Formation and Lower_Cretaceous Jingxing Formation, both of which consist mainly of terrestrial clastic rocks. This leads to the syngenetic model proposed by some authors. The mineralization, however, is not lithostratigraphically restricted. Instead, it is controlled by faulting and doming. The major feeder fault is F 2, a thrust that had been formed at an earlier stage but was modified during the later doming. The orebodies occur in both hanging wall and foot wall. This, together with the absence of hydrothermal sediments and the ore textures of replacement and space_filling, suggests an epigenetic, hydrothermal origin. The Pb isotope data show that the metal is mainly derived from the mantle, mixed with less amounts of crustal lead. The S isotope data show a trend of δ 34 S pyrite >δ 34 S sphalerite >δ 34 S galena , indicating an equilibrium between the min_erals, and the sulphur is mainly of crustal source. The study of fluid inclusions in sphalerite and in associated gangue minerals (quarts, celestine, calcite and gypsum) shows that the homogenization temperatures range from 52℃ to 309℃, clustered around 110～150℃, with salinities of 5.09%～19.63% wt NaCl equivalent. The pressure was 32.5～22.6 MPa, corresponding to an ore_forming depth of 0.9～1.5 km.
出处
《矿床地质》
CAS
CSCD
北大核心
2002年第3期270-277,245,共9页
Mineral Deposits
基金
国家重点基础研究发展规划项目 (编号 :G19990 43 2 0 1)
中国博士后科学基金项目
国家计委地质科学专门项目 (编号 :地科专98_0 1)联合资助
关键词
铅锌矿床
地球化学
地层
构造控制
硫同位素
均一温度
盐度
铅同位素
stratigraphical and structural control, Pb and S isotope, homogenization temperature, salinity, Jinding Pb_Zn deposit
