钾长石中的铅及其对成矿的贡献  

LEAD IN POTASSIUM FELDSPAR AND CONTRIBUTION TO MINERALIZATION

作　　者：张乾[1] 刘志浩[1] 裘愉卓[1] 高计元[2] 王一先[2] 

机构地区：[1]中国科学院地球化学研究所,贵阳550002 [2]中国科学院广州地球化学研究所,广州510640

出　　处：《地质与勘探》2004年第1期45-49,共5页Geology and Exploration

基　　金：国家科技部攀登计划预选项目(编号:95-预-25);国家重点基础研究规划项目(编号:G1999043208)联合资助。

摘　　要：在中—酸性岩浆岩、碱性岩浆岩、片麻岩及混合岩等岩石类型中,钾长石是含铅最高的造岩矿物,其铅含量是全岩铅含量的2～10倍,云母类矿物铅含量的3～16倍,石英铅含量的6～32倍。早元古代、太古宙岩石中钾长石含量低,钾长石中的铅占全岩铅含量的比例低于10%,中元古代以来的碱性岩浆岩、富含钾长石的花岗岩和变质岩,钾长石含量增高,其中所含的铅占全岩铅的比例明显增大,钾长石含量达50%～70%的碱性岩,钾长石中的铅约占全岩总铅量的70%～95%。钾长石在后期极易发生水热蚀变,转变为绢云母、方解石、石英等,在这种转变过程中,铅大量析出进入流体相。这种变化能够为后期铅的成矿提供成矿物质。Potassium feldspar from the middle-acidic and alkaline igneous rocks, gneiss and migmatite possesses the highest lead in comparison with the other rock-forming minerals such as quartz, plagioclase, hornblende, pyroxene, etc. Lead contents in potassium feldspar are 2 to 10 times of the whole rocks, 3 to 16 times of mica and 6 to 32 times of quartz. The rocks of early Proterozoic and Archaean contain the lower potassium feldspar and lead number in potassium feldspar is lower than 10% of lead in the whole rocks. The alkaline rock, kali-granite and metamorphic rocks contain higher potassium feldspar, which content in some rocks may reach 50% to 70% in volume. Lead in potassium feldspar from these rocks reaches the weight of 70% to 95% of the whole rock lead. Potassium feldspar is easily altered and entered generally into sericite, calcite and quartz, etc. In this alteration process, a great quantity of lead in potassium feldspar is released and get into fluids so that to form the ore-forming fluids. Therefore, it is inferred that such changes of lead in potassium feldspar can provide the ore-forming material for late Pb mineralization.

关 键 词：岩石 钾长石 含铅性 成矿作用 

分 类 号：P618.42[天文地球—矿床学] P611[天文地球—地质学]