高光谱蚀变信息在金矿找矿预测中的应用研究——以北山方山口金矿线索为例

Application of hyperspectral alteration information to gold prospecting:A case study of Fangshankou area,Beishan

航空高光谱数据具有丰富的光谱信息和高空间分辨率,在矿化蚀变带识别中发挥着重要作用。成矿地质条件分析表明,北山成矿带方山口—老金场地区存在与中酸性岩体有关的金矿床成矿潜力。覆盖该区的航空高光谱(CASI/SASI)遥感数据蚀变矿物异常提取结果显示,区内发育高铝绢云母、中铝绢云母、低铝绢云母、褐铁矿、白云石、绿泥石、绿帘石和方解石等蚀变矿物。对金滩子金矿床光谱信息的剖析表明,"中—高铝绢云母+褐铁矿"为其标志性蚀变矿物组合;对区内高光谱异常信息进行筛选,圈定出方山口找矿预测区;对预测区内标志性蚀变矿物组合发育地段进行野外查证,发现3条金矿化黄铁绢英岩脉。实践表明,通过针对性地筛选高光谱蚀变矿物异常组合,可以有效地指导下一步的金矿找矿工作。

Hyperspectral Data( CASI/SASI) play an important role in identification of alteration zones for its abundant spectral information and high spatial resolution. In this study,the analysis of metallogenic geological conditions in Fangshankou-Laojinchang area indicates a good potential prospecting of the intrusion-related gold deposits. Anomaly extracting results of CASI/SASI indicate that seven types of alteration minerals,which are Al-high sericite,Al-middle sericite,Al-low sericite,limonite,dolomite,chlorite,epidote and calcite,are mainly developed in this region. Alteration mineral distribution and abnormal composition analysis show that Al-high,Al-middle sericite and limonite are developed in the Jintanzi deposit,which constitute the indicating alteration mineral assemblage for gold mineralization. Then the authors sieved the hyperspectral abnormal information and delineated the Fuangshankou as the ore-prospecting region. Meanwhile,multiple quartz veins which have gold mineralization were found in the field verification process. Therefore the selected indicating alteration mineral anomaly combined with the CASI/SASI is effective for the mineral prospecting.