广西栗木锡钨铌钽矿床岩浆液态不混溶作用及其与矿化的关系  

Liquid Immiscibility of Granitic Magma and Its Relationship with the Mineralization in the Limu Sn-W-Nb-Ta Ore Deposit,Guangxi Province

作　　者：王艳丽[1,2] 彭齐鸣[1,3] 祝新友 程细音 傅其斌[5] 杨毅[5] 

机构地区：[1]中国地质大学(北京),北京100083 [2]有色金属矿产地质调查中心,北京100012 [3]中华人民共和国国土资源部,北京100812 [4]中色地科矿产勘查股份有限公司,北京100012 [5]昆明理工大学国土资源工程学院,云南昆明650093

出　　处：《地质与勘探》2013年第6期1046-1055,共10页Geology and Exploration

基　　金：国家科技支撑课题"湖南锡田地区深部成矿岩体空间结构与成矿预测"(2011BAB04B08);全国危机矿山接替资源找矿项目"湘南-粤北地区锡钨多金属矿床成矿规律总结研究"(20089927)联合资助

摘　　要：锡钨多金属矿化多与Li-F碱长花岗岩有关,其岩浆演化晚期常发生较大规模的液态分异作用。广西栗木锡钨铌钽矿与成矿有关的岩体包括肉红色中粒碱长花岗岩以及顶部的白色细粒碱长花岗岩。矿化产于碱长花岗岩顶部附近,主要矿化类型包括花岗岩型钨锡铌钽矿化、似伟晶岩型钨矿化、长石石英脉型钨矿化和石英脉型钨锡矿化。碱长花岗岩中存在大量岩浆液态不混溶现象,包括矿囊、似伟晶岩和细晶岩等。地质地球化学研究发现,岩浆液态不混溶作用贯穿于栗木碱长花岗岩分异演化的全过程,矿囊代表岩体中富含钨锡和挥发份的岩浆,岩体顶部的似伟晶岩和细晶岩是碱长花岗岩岩浆分异的结果。在岩浆液态不混溶作用过程中,W、Sn、Nb、Ta等成矿元素以及挥发份不断富集,形成岩浆岩型、长英质脉型以及石英脉型矿化。不同类型的矿化对应岩浆液态不混溶作用的不同阶段,由此建立了栗木矿床岩浆液态不混溶的成矿演化模型。Tin-tungsten polymetallic mineralization is generally related to Li-F-rich alkali feldspar granites, and large-scale liquid immiscibility usual- ly occurred in its late magmatic stage. In the Limu tin-tungsten-niobium-tantalum deposit, rock masses related to the mineralization include red medium- grained alkali feldspar granite and white fine-grained alkali feldspar granite （ albite granite）. The mineralization occurred near the top of the alkaline gran- ite, and the main mineralization types include granite-type tungsten-tin-niobium-tantalum mineralization, pegmatite-type tungsten mineralization, feldspar- quartz-vein type tungsten mineralization and quartz-vein-type tungsten-tin mineralization. A liquid immiscibility phenomenon is commonly found in the al- kali feldspar granites, including ore inclusions, pegmatite-aplite dykes and apalite. Geological and geochemical studies show that the liquid immiscibility runs through the whole stage of granite evolution. The ore inclusions represent the magma which is rich in volatile components and W-Sn-Nb-Ta, and the pegmatite-aplite dykes are also the product of liquid immiscibility. In these processes, ore-forming elements of W, Sn, Nb and Ta as well as volatile com- ponents are constantly enriched, forming different kinds of mineralization. The different mineralization corresponds to the different stages of magmatic liq- uid immiscibility. And an ore-forming model of liquid immiscibility evolution is established for the Limu deposit.

关 键 词：碱长花岗岩 液态不混溶 栗木 广西 

分 类 号：P618.510.5[天文地球—矿床学]