论夹皮沟地区金矿床的花岗岩浆热液成因

ON THE GRANITE-MAGMATIC HYDROTHERMAL ORIGIN OF GOLD DEPOSITS IN JIAPIGOU REGION, JILIN

夹皮沟地区金矿床已有三十余年的研究历史,但关于金矿床的成因问题依然是众说纷纭。笔者利用大量的地质地球化学标志,论证了金矿脉与岩脉及岩脉与海西期花岗岩间的同源性,建立起夹皮沟地区海西期岩浆岩脉与金矿脉的形成演化序列。根据金矿脉与花岗岩之间明显的地球化学相似性,进而直接地证明了夹皮沟地区金矿床属花岗岩浆热液成因。

Jiapigou region is rich in gold and is one of the most important gold mining area in China. More than ten of gold deposits and over a hundred gold mineralizations were found along the Jiapigou-Dalazi compressional fault zone in the aureola 0-6 km to the south-west of Huangnihe Granite. In the same area huge quantities of veins were collected. Isotopic ages, the accessory minerals and petrochemistry of the veins are comparable to those of Huangnihe Granite.Trace elements and their abundances and K/Rb, Rb/Sr, Mn/Ti, V/Ti, Co/Ni and Au/Ag ration are almost alike among the veins, the granite and the gold ore-bodies. In the K-Rb,Sr-Ba,Sm-La and(Sm/Fu)sample/(Sm/Eu)chondrite Sm diagrams, the projected points cluster in alike patterns; especially in the last knid of plot which shows the cognate relationship of rocks. The projected points are strictly in linear disposition. The shape, inclination and location of their chondrite-nomalized REE plots are nearly the same. All of their δEu values are positive and δCe values negative.The most important geological characteristics of gold deposits in Jiapigou region is that the gold ore-bodies and the veins coexist spatially and cut each other. According to their cross-cutting, the veins can be divided into three groups: (1)pre-mineralization veins; (2)syn-mineralization veins; and (3)post-mineraliza-tion veins The δD%. values are -86.72 and -86.06 to -91.3 respectively, nearly the same; the type, contents and Cu/Zn, Au/Ag and Co/Ni ratios of trace elements of quartz and magnetite in the granite are similar to those in gold ore-bodies; some ore-forming minerals,such as pyrite, galean, magnetite etc can be found in granite as accessory minerals.All evidences mentioned above undoubtedly indicate that the Huangnihe granite, the veins and the gold ore-bo'dies in Jiapigou region all are the products of a regenerated magma. Therefore the gold deposits in Jiapigou belong to Granite-magmatic hydrothermal deposits.