内蒙古包脑根布墩钼银多金属矿化-蚀变-异常特征及找矿前景分析

摘要

It presented acidic volcanic rocks at upper Jurassic Manketouebo Group.According to the lithologic characteristics,it can be divided into eruption facies,the overflow facies and volcanic sedimentary facies, moreover,mineralized alteration mainly showed silicification,sericitization,chloritization,epidotization, carbonatization,but pyritization and molybdenum mineralization in local area.Volcanic rocks exposed and it was found that Mo and Ag elements in surrounding area exhibited 1∶50 000 chemical exploration anomaly with high strength and large scale; through the anomalies,Mo element peak was 433.4 μg/g and Ag element peak was 3.09 μg/g. Additionally,Mo and Ag elements has the feature of obvious enrichment and strong differentiation in volcanic rock and soil samples with main elements of SiO2 whoes content is 72.30% ~74.26% ,overall,it showed high silicon,aluminum,high degree of differentiation,high potassium calc-alkaline series.The amount of rare earth elements(ΣREE)was high with an average of 173.38×10-6,moderate negative europium anomaly,light and heavy rare earth obvious fractionation,enrichment of light rare earth.After comprehensive analysis,we concluded that the study area has formed potential of molybdenum and silver associated with late Mesozoic acidic volcanic rock and ground.%内蒙古包脑根布墩一带出露上侏罗统满克头鄂博组酸性火山岩，根据岩性特征可划分为爆发相、溢流相和火山沉积相，矿化蚀变主要有硅化、绢云母化、绿泥石化、绿帘石化和碳酸盐化，局部地段见黄铁矿化和钼矿化。火山岩出露区及其周围圈定了一处以 Mo、Ag 元素为主的1∶5万化探综合异常，异常强度高且规模大；通过异常查证，Mo 元素峰值达433.4μg/g，Ag 元素峰值达3.09μg/g。火山岩岩石和土壤样品中 Mo、Ag 元素明显富集，并且具强分异特征；主量元素中 SiO2含量为72.30%～74.26%，总体表现出高硅、过铝质、分异程度高、高钾钙碱性系列的特征；稀土元素总量（ΣREE）较高，平均为173.38×10-6，中等负铕异常，轻重稀土分馏明显，轻稀土富集。综合分析认为，研究区具有形成与中生代酸性火山岩及后期脉岩有关的钼银矿的潜力。