近红外分析提取蚀变信息及其找矿实践--以甘肃岗岔金矿为例

摘要

甘肃岗岔金矿位于秦岭造山带西段北侧之夏河—礼县成矿带西段，属构造破碎蚀变岩型金矿床，目前探明储量已达中型。采用近红外矿物分析技术对矿区蚀变特征的研究结果表明，从远矿到近矿（矿体）存在3个明显特征：①远矿蚀变矿物组合主要为高岭石＋地开石＋蒙脱石±伊利石，近矿蚀变矿物组合主要为白云母＋伊利石±次生石英；②1400 nm 结晶水特征吸收峰、1910 nm 吸附水特征吸收峰和2200 nm Al-OH 特征吸收峰均表现出由远矿至近矿峰型变浅的趋势；③普遍存在的蚀变矿物伊利石，在近矿位置其结晶度高，远矿位置结晶度低。上述分带特征对于进一步找矿具有重要的指导意义。%Gangcha deposit,a medium-size structure controlled alteration type gold deposit,is located in the western section of Xiahe-Lixian metallogenic belt of West Qinling Orogen.In order to study the alteration mineral of the deposit,short wave infrared spectral mineral analysis technology was applied,and two alteration zones had been identified from wallrocks to ore bodies.In this study:we ① identiied the compositions of muscovite +illite +secondary quartz were close to ore bodies,and kaolinite +dickite +montmorillonite ±illiten were far away from ore bodies;② found the trends of 1 400 nm,1 910 nm and 2 200 nm characteristic absorption peak turned to be shallow as it closed to the ore bodies;③ found the crystallinity trend of illite was better when it closed to ore bodies.These provided new ideas for the further exploration of Gangcha deposit.