大兴安岭南段森林沼泽区地球化学找矿方法研究——以内蒙古呼伦贝尔市忠工屯一带1∶5万矿调为例

Geochemical Method for Prospecting Minerals in the Forest and Swamp Area of Southern Daxinganling Mountains:Example from the 1∶50 000 Mineral Survey in Zhonggongtun Area,Hulun Buir City,Inner Mongolia

分析了大兴安岭南段森林沼泽景观地球化学的特征,根据地形地貌、水流、植被和沉积物介质成分,将森林沼泽区水系-沟谷体系划分为8种类型。总结出该类地区表生条件下元素迁移、集散、分布规律,Pb、As、Sb、Mn和部分Au、Mo常分布于较粗粒级,富集于-4^+40目粒级的概率是46%~71%;而Ag、Cu、Zn、Hg和部分Au较多分布于细粒级,富集于-4^+60目的概率是46%~60%。根据水系沉积物测量结果,统计计算了主要地质单元的元素含量和变异系数,计算了各地质单元元素平均含量与测区平均含量的比值,以此来研究和说明元素在区内各地质单元的分布、分配和富集特征。据此,在矿调工作中,应用森林沼泽景观中地球化学工作方法与异常查证评价技术,在大兴安岭南段森林沼泽区查证了大量的找矿线索。

The geochemical characteristics of the forest swamp landscape in the Southern Daxinganling Mountains have been analyzed in this paper.According to the landform,water,vegetation and sediment composition,the river-valley system in the forest swamp area has been divided into 8types.The migration,gathering and distribution of elements under the supergene conditions in the area have been summarized.Pb,As,Sb and Mn elements,as well as some Au and Mo elements are distributed as relatively coarse grain,which are concentrated on-4to +40mesh with the probabilities of grain size range from 46%to 71%;But Ag,Cu,Zn,Hg and partially Au elements are mainly distributed in coarse grade,which are concentrate on-4to +60,with the probabilities of grain size vary from 46% to 60%.Based on the measurement results ofstream sediments,the element content and variation coefficient of main geological units have been counted and calculated;the element mean content ratio between each geological unit and sensing area has been calculated.And then,the element distribution,allocation and enrichment characteristics of various geological units have been studied and explained.Finally,the geochemical survey method and the anomaly inspection evaluation techniques have been used in the forest swamp landscape area during carrying out the mineral survey project,and lots of prospecting clues have been verified in the forest swamp landscape area of Southern Daxinganling Mountains.