论文部分内容阅读
云南马关都龙锡锌多金属矿床位于滇东南老君山锡锌钨多金属成矿区南部,是我国三大锡石硫化物矿床之一,其地质及成矿作用复杂,矿物种类繁多。本文根据矿床中矿物共生组合特征,从早到晚划分出以下4个阶段:(a)夕卡岩阶段,早期为无水夕卡岩阶段,形成矿物以石榴石和透辉石为主,晚期为含水夕卡岩阶段,形成矿物以阳起石、绿帘石、绿泥石和符山石等为主;(b)氧化物阶段,磁铁矿、锡石和白钨矿等氧化物在此阶段大量沉淀;(c)硫化物阶段,早期形成磁黄铁矿→黄铁矿→黄铜矿、辉钼矿,晚期形成闪锌矿(黄铜矿)和少量方铅矿组合;(d)碳酸盐阶段(方铅矿及少量闪锌矿),其成矿元素与夕卡岩蚀变类型的垂直分带特征与典型夕卡岩型矿床较类似,矿化类型和围岩蚀变的分带与隐伏岩体距离有关,该矿床属于与燕山晚期花岗岩有关的岩浆热液夕卡岩型多金属矿床。流体包裹体研究结果表明,从成矿早阶段到晚阶段,成矿流体从中高温较高盐度逐渐演化为中低温低盐度流体,压力的降低和大气降水的混入造成的流体沸腾可能是Sn和Zn等成矿元素大量沉淀的主要机制。该研究成果为认识都龙矿床成矿作用提供了实际地质和地球化学依据。
Located in the southern part of the Laotun Mountain tin-zinc-tungsten polymetallic ore deposit in southeastern Yunnan, Yunnan Maguan Du Long Tin-Zinc polymetallic deposit is one of the three Cassiterite sulfide deposits in China. Its geology and mineralization are complex with a wide variety of minerals. Based on the characteristics of mineral assemblages in mineral deposits, the paper divides four phases from early to late: (a) the skarn stage, the early anhydrous skarn stage, the garnet and diopside-forming minerals, and the late stage Hydrous skarn stage, the formation of minerals to actinolite, epidote, chlorite and Fu Shan, etc .; (b) oxide stage, magnetite, cassiterite and scheelite and other oxides at this stage a large number of precipitation ; (c) In the sulphide phase, pyrrhotite → pyrite → chalcopyrite and molybdenite are formed in the early stage, and the late combination of sphalerite (chalcopyrite) and a small amount of galena (d) carbonate Stage (galena and a small amount of sphalerite), the vertical zoning characteristics of the ore-forming elements and skarn alteration types are similar to the typical skarn-type deposits. The mineralization types and the zonal alteration of the wall rocks are similar to Hidden rock mass distance related to the deposit belongs to magmatic hydrothermal skarn type polymetallic deposits related to Late Yanshanian granite. The results of fluid inclusions show that from the early to late stages of mineralization, the ore-forming fluids gradually evolve from medium-high temperature and high salinity to low and medium temperature and low salinity fluids. The fluid boiling caused by the pressure drop and atmospheric precipitation mixing may be Sn And Zn and other ore-forming elements of the main precipitation mechanism. The research results provide practical geological and geochemical basis for understanding the mineralization of Du Long deposit.