基于短波红外技术的西藏多龙矿集区铁格隆南矿床荣那矿段及其外围蚀变填图-勘查模型构建

Alteration mapping and prospecting model construction in the Tiegelongnan ore deposit of the Duolong ore concentration area, northern Tibet, based on shortwave infrared technique

采用短波红外技术测量西藏多龙矿集区铁格隆南矿区地表岩石样本,发现蚀变矿物主要有绢云母和绿泥石,并在地表形成了一套从绢英岩化带-青磐岩化带的具有斑岩特点的蚀变矿物组合特征。通过测量地下ZK0804,ZK1604,ZK2404,ZK3204四个钻孔岩心的短波红外特征,发现钻孔岩心中存在大量明矾石、高岭石、地开石和绢云母,在东西向展布的过程中,绢云母数量及厚度明显增大,有继续向下延伸的趋势,说明矿体向深部逐渐从富含明矾石、地开石、高岭石的高硫、低温类型的矿物组合向绢英岩化带转变,并构成了规律的蚀变分带系统。根据地表、地下岩(矿)石的短波红外光谱特征及蚀变矿物分布趋势,构建了基于短波红外勘查技术的多龙矿集区斑岩-高硫浅成低温热液型铜(金)矿床找矿勘查模型,总结了从钾化带-绢英岩化带-泥化带-高级泥化带(明矾石-地开石-高岭石组合)-青磐岩化带的一套完整蚀变矿物组合及光谱特征。

The discovery of the Rongna deposit was a breakthrough in 2013.This deposit was considered as the porphyry-epithermal type deposit,because alteration minerals occur in the surface rock samples which were measured by shortwave infrared and geochemical technique;nevertheless,they are mainly muscovite and chlorite.These minerals form a characteristic alteration system from the outer phyllic to propylic zone.The measuring of the drill cores ZK0804,ZK1604,ZK2404,ZK3204 with the instrument ASD revealed that abundant minerals like alunite,kaolinite and muscovite are existent and coexist with copper.From ZK804 to ZK3204,the abundance of alunite decreases and disappears in ZK3204,but muscovite increases.The combination characteristics of alteration minerals can illustrate the deposit type characterized by the transition from epithermal deposit to porphyry deposit.According to the surface and underground mineral distribution of rock samples,a model about porphyry-epithermal deposit was constructed on the basis of shortwave infrared technique which shows the spectral and type variations of minerals and distribution features.The result obtained by the authors is a good reference for the prospecting with the shortwave infrared technique.