Short Wave Infrared Spectral Analysis Extraction Alteration Information and Prospecting Practice-A Case Study of Gangcha Gold Deposit, Gansu

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.