大兴安岭北段南木地区斑岩型铜矿地质特征与成矿预测

南木火山盆地位于大兴安岭中北段的林西-扎兰屯多金属成矿带中,是华北板块北部大陆边缘与西伯利亚板块东南陆缘增生带的交汇部位. 侵入岩以岩株、岩脉出露为特征,岩性以花岗斑岩、石英斑岩为主. 蚀变类型主要有绢云母化、褐铁矿化、硅化和绿泥石化,构成多条蚀变带. 在1:5万矿产调查评价工作基础上,采用激电中梯与激电测深两种方法进行金属矿产勘查. 研究发现低阻、高极化异常带与地表岩脉矿化部位及土壤地球化学异常吻合良好. 研究区圈定激电异常4处,测深穿过JD2高极化、中低阻层,推测地下存在含铜石英斑岩体. 综合地质、化探及物探特征,南木地区斑岩体、孔雀石化和激电异常均有存在,具有一定的深部找矿前景.

GEOLOGY AND METALLOGENIC PREDICTION OF PORPHYRY COPPER DEPOSIT IN NANMU AREA,NORTHERN DAXINGANLING MOUNTAINS

Located in the Linxi-Zhalantun polymetallic metallogenic belt in central-northern Daxinganling Mountains, Nanmu volcanic basin is the intersection between northern continental margin of North China Plate and southeast continental margin accretion zone of Siberian Plate. The intrusive rocks are outcropped as stocks and dikes, lithologically dominated by granite porphyry and quartz porphyry. The main alteration types of sericitization, ferritization, silicification and chloritization form multiple alteration zones. The methods of induced polarization (IP) intermediate gradient and IP sounding are used for metal mineral exploration on the basis of 1:50 000 mineral survey and evaluation. The results show that the low-resistivity and high-polarization anomaly zones are in good agreement with the surface dike mineralization sites and soil geochemical anomalies. Four IP anomalies are delineated in the area, with the deep sounding section passing through the JD2 high-polarization, low-middle resistivity layer. It is inferred that there is copper-bearing quartz porphyry body underground. Combined with the geological, geochemical and geophysical characteristics, the existence of porphyries, malachite mineralization and IP anomalies in Nanmu area suggest a certain prospect of deep exploration.