中文摘要:凤太层控铅锌矿床赋存于中泥盆统古道岭组灰岩与星红铺组千枚岩接触带或隐伏背斜构造鞍部，受地层、构造控制明显；有清楚的硅化、铁自云石化、炭沥青化等围岩蚀变现象，主要矿石矿耪为闪锌矿、方铅矿、黄铁矿、黄铜矿及毒砂等。根据矿物包裹体、矿石和上下盘围岩组分比值、矿石矿物微量元素分布、硫铅同位素组成、区域围岩元素丰度等一系列特征，推测矿质极可能来自深部古加里东岛孤基底，后经海西一印支期构造作用，通过地下热卤水渗流，再到上部有利圈闭空间富集成矿。矿床成因类型基本属古生新储层控再造矿床。上部围岩也可能提供部分矿质，但主要矿源层应在深部。
Abstract:Studies show that mineral inclusions are mainly tiny fluid ones(2-3μm), with no daughter minerals observed. The homogenization temperatures of sphalerite and galena are between 200-300℃, their salinities are about 10 percent, and the fluid type is of Ca2+一Mg2+一K+一HCO3-一Cl-一F- type. There exist obvious differences between the ore and the country rocks in such aspects. as the proportion of SiO2: Al2O3: MgO, the ratios of K/Na and Co/Ni, the contents of organic carbon, Cl, Mg, SiO2 and H2O+, as well as the pH values, suggesting noncontemporaneous deposition characteristics of the ore. Galena is rich in As and poor in Sn, with the ratio of Sb/Bi(=4)somewhat lower. Galena and sphalerite are comparatively high in Se and low in S/Se. Sphalerite is rich in Fe, Mn, Cu, Cd and poor in Ge, Zn. Orebodies are closely associated with Hg. All these characteristics suggest a high ore-forming temperature and the derivation of metallogenic materials from the depth. Sulfides in the orefield have δ34S values of -1.5—12.8‰ andδ34S∑S values of 7.5—15.2‰, lower than the average value of sulfates in sea water(20％), implying the probable addition of sulfur from the depth. The model age of lead is averagely 440 Ma, older than Middle Devonian strata. This indicates that lead might come from the depth. The ratios of 206Pb/204Pb,207Pb/204Pb and 208Pb/204Pb range from 17.982—18.096, 15.559—15.656 and 37.977—38.404 respectively, with the differences less than 0.5. These ratios are all within the range of island arc type lead, having the characteristics of mixed crust-mantle lead. The volcanic island are (O)on the old basement of the northern neighboring area and the ferrodotomitic phyllite in the ore field have rather high abundances of metallogenic elements (Pb 27一110 ppm, Zn 58一l85 ppm), suggesting that they might serve as the ore source beds. In the ore field, magmatic and volcanic rocks are seldom seen, there are no volcanic components in the ore, and wall rock alterations are quite simple. The above discussion demonstrates that the ore deposits in this area are quite different from Common sedimentary deposits, and also fail to show characteristics of typical magmatic-hydrothermal deposits. It is therefore concluded that these deposits should be of sedimentary-reworked type, with the repeated infiltration of the underground hot brine acting as the key reworking factor.
文章编号：
中图分类号：
文献标志码：
引用文本：
王海山.1988.陕西省风太层控铅锌矿床地球化学特征及其成因探讨[J].矿床地质,7(1):54~63.1988.Geochemical characteristics and genetic discussion of the stratabound lead-zinc ore deposits in fengtai, Shaanxi province[J].Mineral Deposits7(1):54~63
图/表
