河南泌阳红石山一带二郎坪群地质地球化学特征及成矿认识

摘要

泌阳红石山一带二郎坪群变火山岩分布于朱庄背构造的北部,锌、铜、铅、银矿化较发育,在刘山岩组中多金属矿(化)体的规模较大,多赋存于与变石英角斑岩接触的变细碧岩一侧或矽卡岩之中.本区铁镁质火山岩的常量元素、微量元素及过渡元素特征显示其成于弧后盆地,但是部分常量元素和微量元素较南部火山岩有增有减,说明南北两地火山岩成分可能因出露位置、后期改造等存在着差异;区内铜锌矿石及绿帘石化围岩(斜长角闪岩)与变基性岩的REE分配模式基本一致,可能是继承了海底基性火山岩和石英角斑岩REE分配曲线的特征.根据二郎坪群主要赋矿地层(刘山岩组)中相关成矿元素的分配特征分析,成矿元素和主要伴生元素(除Ba外)的平均含量,均高于南部刘山岩组,但富集系数相对偏低;就成矿元素Cu、Zn来看,Zn的富集系数大于Cu,成矿能力更强,符合该区矿化的分布规律,是下一步找矿的主攻矿种.%Erlangping Group volcanic rocks in Hongshishan area of Biyang County are distributed in the northern antiform of Zhuzhuang,and mineralization of Zn,Cu,Pb,Ag is developed.There are large-scale polymetallic orebodies (mineralized bodies) in Liushanyan Formation and most of them occur in one side of metamorphic spilite which is in touch with metamorphic quartz keratophyre or skarn.In this area,major element,trace element and transition element characteristics of mafic volcanic rocks show that they are formed in back-arc basin,but part of the major elements and trace elements are more or less than those of the southern volcanic rocks.It is suggested that the composition differences may exist between the south and north volcanic rocks because of the exposed position and late reformation.REE distribution pattern of copper-zinc ore and epidotization wall rocks (amphibolite) are basically the same as that of metamorphic basic rocks.It is possible that they have inherited REE distribution pattern feature of submarine mafic volcanic rocks and quartz keratophyre.According to distribution feature analysis of relevant ore-forming elements of main ore bearing strata (Liushanyan Formation) of Erlangping Group,the average contents of ore-forming elements and main associated elements (except Ba),are higher than those of the southern Liushanyan Formation,but the enrichment ratio is relatively lower.For ore-forming elements such as Cu and Zn,enrichment ratio of Zn is greater than that of Cu,it is indicated that Zn has stronger mineralization ability and this result is conformed to the mineralization distribution regularity in this area.Therefore,Zn is one of the main mineral resources in the next prospecting.