摘要
2014年发现的维拉斯托锡锌矿是继20世纪末该矿区铜锌矿之后的重要找矿进展,已控制Sn金属资源量10万t。成矿作用与隐伏花岗岩体有关,该岩体侵入于前寒武纪变质岩中。矿化类型包括岩体顶部的花岗岩型锡锌矿、岩体外侧的石英脉型锡锌矿以及外围的铜锌矿。针对花岗岩、各类矿体开展了岩石学、矿床学、主微量元素地球化学、年代学等研究,初步查明岩浆演化机制、矿床成因及三类矿化的关系。细粒斑状碱长花岗岩La-ICPMS锆石UPb年龄(139.5±1.2)Ma(MSWD=3.3)。岩石中发育多级斑晶,结晶(沉淀)顺序为钠长石→石英→钾长石→钠长石→石英、黄玉、锡石、闪锌矿。花岗岩富Si O2贫Al2O3、Ti O2、TFe2O3、Ca O等,高Rb、Cs、Nb、Ta及W、Mo、Bi、Cu、Zn、In等元素,低Sr、Ba等,钠长石An<0.3,与锡钨多金属矿成矿花岗岩性质相似。岩浆晚期经历了岩浆-热液过渡阶段(浆液过渡态流体),自硅酸盐相中分离出富Si、富F和富S的流体相,分别形成花岗岩型矿石中的石英、黄玉、锡石-闪锌矿囊状体(珠滴),伴随熔融包裹体和熔流包裹体,晚期逐渐、连续地向热液阶段过渡。岩浆-热液过渡阶段在岩体顶部形成花岗岩型锡锌矿石,热液阶段在岩体外侧和外围形成石英脉型锡锌矿及铜锌矿、铅锌银矿。这些矿体连同成矿花岗岩共同构成岩浆-热液型锡多金属矿床成矿系统。锡林郭勒—赤峰地区,很多脉状铅锌银矿的成矿作用与酸性侵入岩有关,深部可能存在大规模岩浆-热液型锡(钨)多金属矿。
The Weilasito Sn-Zn-Cu deposit is located in Keshiketen, Inner Mongolia, at latitude 44°5＇5 ＂N,longitude 117°29＇53＂ E.The mineralization styles include granite-type Sn-Zn at the top of the granite, quartz vein type Sn-Zn ore near the granite, Cu-Zn sulfide vein and Pb- Zn- Ag sulfide vein distal from the granite. Based on petrology, geology and geochemistry of elements and chronology, the authors recognized the granite magma revolution, the origin of the deposit and the relations between the mineralization styles. LA-ICP-MS zircon U-Pb dating yielded a weighted mean^206Pb/^238 U age of 139.5±1.2Ma（MSWD=3.3）for the alkali feldspar granite pluton. There are multilevel phenocrysts in the pluton, and the crystallization sequence is albite- quartzK- feldspar- albite- quartz, topaz, cassiterite, and sphalerite. The granite rich in Si O2 and Rb, Cs, Nb, Ta, W, Mo, Bi, Cu, Zn, In etc., poor in Al2O3, Ti O2, TFe2O3, Ca O and Sr, Ba etc., the An value of the albite is lower than 0.3, similar to data of the granite of Sn- W deposits in the Nanling belt. Late magma experienced magmatic- hydrothermal transitional stage as well as gradual continuous evolution to hydrothermal stage. The Si rich, F rich and S rich fluid phases were separated from the magma to form the droplets（pocket） of quartz, topaz, cassiterite- sphalerite respectively in the granite-type Sn-Zn ore. The fluid inclusions are melt,melt-fluid and liquid respectively. The granite-type Sn-Zn ore formed at the top of pluton at the magma-hydrothermal transitional stage, the quartz vein-type Sn-Zn ore occurs at the outer part and the sulfide-vein Cu-Zn, Pb-Zn-Ag ore of the hydrothermal stage occurs distal from the rock body. All of the ores and the plutons comprise the magmatic hydrothermal tin polymetallic metallogenic system. In Xilin Gol- Chifeng area, there are some Pb- Zn- Ag veins（deposits and/or mineralization） related to the acidic intrusive rocks. There probably exsit large-sized hydrothermal tin（tungsten） polymetallic deposits in the depth.
出处
《中国地质》
CAS
CSCD
北大核心
2016年第1期188-208,共21页
Geology in China
基金
国家科技支撑课题(2011BAB04B08)
国土资源部公益性行业科研专项(201411024)
中国地质调查局工作项目(12120113086300)联合资助~~
关键词
锡矿
铅锌银矿
花岗岩型
石英脉型
浆液过渡态流体
成矿机制
成矿系统
内蒙古
tin deposit
lead-zinc-silver deposit
granite type
quartz vein type
magma-hydrothermal transitional fluid
metallogenic mechanism
metallogenic system
Inner Mongolia
作者简介
祝新友，男，1965年生，教授级高级工程师，长期从事矿床学研究；E—mail：zhuxinyou@outlook．com。
