甘肃北山红柳园—辉铜山地区成矿地质条件、地球化学特征及找矿新发现

Metallogenic geological conditions,geochemical characteristics and new discovery of ore prospecting in Hongliuyuan-Huitongshan area of Beishan in Gansu Province

甘肃北山红柳园—辉铜山地区位于甘肃北山南带,是形成铜、镍、铁、铅锌、钼、金、银等矿床的有利地区,具有较好的找矿潜力。通过开展成矿地质条件分析,总结控矿关键因素,依据水系沉积物地球化学特征,确定Au、Ag、As、Sb、Hg、W、Sn、Ni、Cu为区内主要的成矿(伴生)元素。Ni、Cu异常与基性-超基性侵入岩的分布有关,Au异常受华力西中期似斑状花岗岩及加里东晚期石英闪长岩控制明显,与区域性断裂及其旁侧平行或“入”字斜交的次级断裂关系密切。异常查证新发现铭扬铜镍矿、杨帆金矿等多处矿点及矿化线索,结合区域地质、物探、化探特征,优选出4处具较大成矿潜力的找矿远景区,尤其是早古生代铭杨铜镍矿的发现,实现了北山地区近年来铜镍矿找矿新突破。研究成果可为下一步找矿勘查部署提供重要依据。

The Hongliuyuan-Huitongshan area is located in the southern Beishan belt of Gansu Province,which is a favorable area for forming copper,nickel,iron,lead zinc,molybdenum,gold and silver deposits with good prospecting potential.By carrying out the analysis of geological conditions of mineralization,and summarizing the key factors controlling mineralization,the authors identified Au,Ag,As,Sb,Hg,W,Sn,Ni and Cu are the main ore-forming(associated)elements in the area,according to the geochemical characteristics of stream sediments.The anomaly of Ni and Cu is related to the distribution of basic-ultrabasic intrusive rocks,while the anomaly of Au is obviously controlled by the middle Warissian-porphyritic granite and the Late Caledonian quartz diorite.Besides,the anomaly of Au is also closely related to the regional faults and secondary faults that are parallel or oblique.A number of ore sites and mineralization clues were newly discovered in Mingyang copper-nickel mine and Yangfan gold mine through anomalous investigation.Four prospecting areas with great metallogenic potential were optimized based on the analysis of regional metallogenic geological conditions and the characteristics of geophysical and geochemical exploration.Especially,the discovery of Mingyang copper-nickel deposit in Early Paleozoic has achieved a new breakthrough in copper-nickel ore prospecting in Beishan area in recent years.The research results could provide an important basis for further prospecting and deployment.