短波近红外光谱蚀变填图在黑龙江某岩金矿床找矿勘查中的应用

Application of short-wave near infrared spectrum in alteration mapping of a gold deposit in Heilongjiang

黑龙江某岩金矿床位于大兴安岭北段,是近年来在该区发现的为数不多的岩金矿床之一。矿区内分布了多期次的构造活动,同时伴随岩浆岩的侵入,流体活动范围很广泛,造成了较强的围岩蚀变。主要蚀变类型包括黄铁绢英岩化、青磐岩化和硅化等。近年来,利用短波红外光谱识别蚀变矿物,进而通过蚀变特征指导找矿方面取得了较好的成果。介绍了利用短波近红外光谱对该金矿区开展蚀变填图以及分析蚀变矿物分带最终指导找矿的实例。该区通过短波近红外光谱测量发现了6种蚀变矿物:伊利石、蒙脱石、高岭石、白云母、绿泥石、石英等。观察表明,区内的金矿体与硅化和伊利石化有关,因此根据测试结果,圈定了伊利石化和硅化发育的区域,同时利用伊利石结晶度来指示热液活动的中心和可能的扩散方向,为找矿提供指导。

One gold deposit is found in recent years as one of the few rock gold deposits located in the northern part of the Greater Khingan Mountains. In the mine area,there are multiphase tectonic activities,and with magmatic intrusion,the range that fluid activities cover is very broad creating a strong wall rock alteration. The main alteration types include beresitization,propylitization and silicification. In recent years,the use of short-wave infrared spectrum has achieved good results in identifying altered minerals,and then guided prospecting through alteration features. This paper introduces an application case that the short-wave infrared spectrum is used in a gold deposit to carry out alteration mapping and the analysis of alteration mineral zoning to guide prospecting. Finally in the mine area,6 types of alteration minerals are found： illite,montmorillonite,Kaolinite,white mica,chlorite and quartz. Observation shows that gold orebodies in the area are associated with silicification and illitization. So according to the test results,the anomalies of illitization and silicification are delineated,and at the same time,the iillite crystallinity is used to indicate the center of the hydrothermal activities and the possible diffusion direction,providing guidance for prospecting.