粤北石英脉型钨多金属矿床中钨锡铋银钼的赋存状态研究

Occurrence Modes of Tungsten,Tin,Bismuth,Silver and Molybdenum from the Vein Type Tungsten Polymetallic Deposits in Northern Guangdong,China

本文对粤北红岭、石人嶂、梅子窝、锯板坑等四个石英脉型钨矿的矿石样品进行了详细的矿相学和电子探针分析,在红岭钨矿中观察到黑钨矿与白钨矿共生或交代现象,并发现铌锰矿、(含)钨铌锰矿晶体。在石人嶂、梅子窝、锯板坑钨矿中发现较多黝锡矿,分布在黄铜矿、闪锌矿边缘,或呈乳滴状分布在黄铜矿中,部分黝锡矿中包裹锡石。红岭、石人嶂、梅子窝钨矿床中有不同程度的银矿化,根据(含)银矿物的能谱成分分析,区分出富硫铋铅矿、块辉铋铅银矿(第1、2、3亚种)、硫银铋矿、淡红银矿、脆银矿、硫铜银矿,并有含银4.78%～13.25%的硫铅铋盐、含银2.9%～12.19%的硫铜银盐、含银71.01%～90.74%的硫砷银盐及含银9.3%的硫氯铅铜盐等多种未定名矿物。红岭钨矿中含银矿物多以不规则粒状分散在铁闪锌矿、硅酸盐矿物中,含银矿物与主硫化物同时形成;石人嶂钨矿床中含银矿物主要为含银硫铜盐、硫铜银盐,在黄铜矿边缘形成含银矿物-闪锌矿的交代反应边,局部有含银硫铅铋盐、硫铋银盐;梅子窝钨矿床中主要为独立银矿物和少量自然银,多分布在方铅矿中或充填在硫化物裂隙中,含银硫铅铋盐、硫铋盐、硫砷铅银矿物较少。石人嶂、梅子窝钨矿床中银矿物种类丰富且含量较高,具有综合利用前景,两矿床部分样品中发育细脉型或边缘交代型的(含)银矿物,表明晚期热液叠加银矿化作用较强。四个矿床中的铋矿物主要为辉铋矿和自然铋,部分矿床中多含银铅铋硫盐类,在红岭钨矿中发现与辉铋矿共生的楚碲铋矿,石人嶂钨矿中有细脉状未定名铋铜硫盐。四个矿床的闪锌矿成分不同,石人嶂、梅子窝钨矿的含较高Cd,红岭、锯板坑钨矿的基本不含Cd,红岭钨矿闪锌矿中Fe含量变化较大。

Detailed mineragraphy and electron probe analysis were carried out on the samples from Hongling,Shirenzhang,Meiziwo and Jubankeng vein type tungsten deposits in northern Guangdong,China.We found several grains of mangancolumbite and wolframoixiolite and observed a wide range of intergrowth phenomenon of wolframite and scheelite in the Hongling deposit.A large amount of stannite found in Shirenzhang,Meiziwo and Jubankeng tungsten deposits are distributed along the edges of chalcopyrite and sphalerite or occurs as disseminated drops in chalcopyrite.Some stannites even include cassiterite.Silver mineralization to some extent occurs in the Hongling,shirenzhang and Meiziwo tungsten deposits.Based on the EDX analysis of Ag-bearing minerals,Ag-bearing heyrovskyite,schirmerite（No.1,2,3 subspecies）,matildite,proustite,stephanite,an stromeyerite have been identified with minor unnamed Pb-Bi-S minerals（4.78%~13.25% Ag）,Ag-Cu-S minerals（2.9%~12.19% Ag）,As-S-Ag minerals（71.01%~90.74% Ag）,and Cl-Pb-Cu-S mineral（9.3% Ag）.Silver-bearing minerals in the Hongling deposit are mainly scattered as irregular grains in sphalerite and silicate minerals,and formed simultaneously as the main sulfides did.Ag-bearing minerals in the Shirenzhang deposit mainly contain Ag-bearing Cu-S minerals and Ag-Cu-S minerals,which form Ag-bearing mineral sphalerite belt at the edge of chalcopyrite,while Ag-bearing Pb-Bi-S and Bi-Ag-S minerals distribute locally.Meiziwo deposit contains less Ag-bearing Pb-Bi-S,Bi-S and As-Pb-Ag minerals but independent silver minerals and small amount of natural silver occurring in galena and filling the fractures of sulfides.There are various Ag-bearing minerals with high contents in the Shirenzhang,Meiziwo tungsten deposits indicating good prospect of development.Metasomatic Ag-bearing minerals developed and filling along fractures of the samples from two deposits indicate a strong silver mineralization imposed by late-stage hydrothermal fluid.Bismuth minerals in the four deposits are mainly bismuthinite and bismuth and part of the deposits are dominated by Ag-Pb-Bi sulfosalt.Several grains of tsumoite were found in the Hongling deposit and are paragenetic with with bismuthinite;unnamed Cu-Bi-S minerals were found in the Shirenzhang deposit.Compositions of the sphalerites from the four deposits are different,Hongling and Jubankeng deposits containing no Cd and the Shirenzhang and Meiziwo deposits containing higher Cd content.But iron content in the Hongling tungsten deposit varies greatly.