冀西石湖金矿黄铁矿和石英的晶胞参数特征及其地质意义

Characteristics of Cell parameters of Pyrite and Quartz and Their Geological Significance at Shihu Gold Deposit in Western Hebei,North China

将石湖金矿的成矿过程划分为4个阶段:黄铁矿-石英阶段,石英-黄铁矿阶段,多金属硫化物阶段和石英-碳酸盐阶段。分别对4个成矿阶段中的黄铁矿和石英进行了晶胞参数测定。结果表明,黄铁矿的a0和0υ随着成矿阶段的演化和深度的增加有减小的趋势,且主成矿阶段为最小值;石英的c0和c0/a0从Ⅰ→Ⅳ阶段具有减小的趋势,石英a0值随深度增加而变大,而c0值和c0/a0随深度增加呈韵律式变化。根据晶胞参数推测,黄铁矿中Co、Ni、As含量高,且未发生S亏损;石英类质同象以Al、Fe等置换杂质为主。本区含矿黄铁矿和石英的晶胞参数分别以a0值较小和a0值较大,c0值较小,c0/a0值较小为特征。黄铁矿的a0和石英的c0和c0/a0绝大多数大于理想值,所以矿体剥蚀不大,深远景广阔。

Gold Mineralization of the Shihu deposit can be divided into 4 stages,pyrite-quartz stage,quartz-pyrite stage,polymetallic sulfide stage and quartz-carbonate stage.Cell parameters of pyrite and quartz from 4 stages were analyzed in this paper.The analytical results of pyrite indicated that the value of a0 and υ0 is minimum in Ⅲ stage;the values of a0 and υ0 decrease as mineralization stage proceeds from Ⅰto Ⅳ and as the depth of ore-body increases from 560 to 180 meters.The analytical results of quartz indicated that the values of c0 and the c0/a0 ratios decrease as mineralization stage changes;the values of a0 increase as the depth of ore-body increases;the values of c0 and the c0/a0 ratios change rhythmically as the depth of ore-body increases.Results of cell parameters suggested that pyrites have high contents of Co,Ni and As,and have not undergone S depletion.Moreover,Al and Fe are the major replacement impurities in isomorphism of quartz.Gold-bearing pyrites are characterized by small a0,while gold-bearing quartz are characterized by big a0,small c0 and c0/a0 ratio.The values of a0 of pyrite and the values of c0 and c0/a0 ratios of quartz are mostly larger than their ideal values.Therefore,denudation of the gold ore-body is slight,and potential value of this deposit is considerable.