开库康-依西肯地区原生晕地球化学特征及找矿意义

Geochemical characteristics and prospecting significance of primary halo in Kaikukang-Yixiken area

为指导水系沉积物测量等化探异常的解释评价,分析成矿元素地球化学特征,评价主要地质单元含矿性,在开展1∶5万水系沉积物测量的同时系统采集了研究区内各地质单元原生晕样品,并对成矿元素进行了地球化学参数统计与对比研究。原生晕地球化学特征表明:区内以中低温热液成矿作用为主,找寻Au矿化或矿床希望较大,As、Sb等元素可作为指示元素;主要地质单元含矿性评价结果显示,研究区内上侏罗统二十二站组、下白垩统龙江组为区内成矿有利部位,主成矿元素为Au,Ag为伴生元素;水系与岩石样品对比分析表明,As、Sb、Mn、Mo 4种元素表现明显次生富集,Zn、Cu、Ti 3种元素明显贫化,在水系异常圈定时应适当提高、降低异常下限。

This paper aims to evaluate and explain the secondary geochemical anomalies better for surveying stream sediment,analyze the geochemical characteristics behind ore-forming elements,and evaluate the ore-bearing potential of major geological units.The study consists of systematically collecting primary halo samples of each geological unit in the study area,as happens when surveying the 1:50000 stream sediment;and conducting geochemical parameter statistics and comparative analysis on ore-forming elements.The geochemical characteristics behind the primary halo show that the mineralization in the region relies mainly on the medium and low temperature hydrothermal solution,where existing great feasibility of AU mineralization and deposits,and As,Sb and other elements can be used as indicating elements.The ore bearing evaluation results of the main geological units show that the favorable metallogenic locations lie in Upper Jurassic Ershierzhan Formation and Lower Cretaceous Longjiang Formation with the main metallogenic element Au,and the associated element Ag.The results show that by the comparative analysis of stream sediment samples,the four elements of As,Sb,Mn and Mo show obvious secondary enrichment,and the three elements of Zn,Cu and Ti are obviously depleted,which should be appropriately increased at anomaly of stream sediment,and to reduce the anomaly threshold.