内蒙古陈巴尔虎旗八大关铜钼矿岩石地球化学特征及U-Pb、Re-Os年龄

得尔布干成矿带是中国东北地区中、俄、蒙毗邻区域一条重要的铜、钼、金、铅锌多金属成矿带,控制产出大量多金属矿床。满洲里—陈巴尔虎旗一线集中产出铜钼矿,如乌奴格吐山铜钼矿、八大关铜钼矿、八八一铜钼矿。然而与相邻俄罗斯额尔古纳—上黑龙江—岗仁成矿带中的铜钼矿产出现状对比,无论数量还是规模均相差甚远,显示仍存在较大找矿空间。在近年来大量野外地质工作及矿床实际考察基础上,阐述了八大关铜钼矿矿床地质特征。通过岩石地球化学特征研究、LA-ICPMS锆石U-Pb及辉钼矿Re-Os年龄测试,确定八大关铜钼矿为形成于印支晚期(205.8±3.4Ma),受八大关短轴背斜及NE-SN向断裂控制的造山带斑岩型铜钼矿。与乌奴格吐山铜钼矿对比,八大关矿区形成于燕山早期的花岗质斑岩体极有可能是新的铜钼赋矿体。

Geochemical characteristics of rocks and U-Pb, Re-Os age of the Badaguan Cu-Mo deposit in Chen Barag Banner,Inner Mongoli

The Derbugan metallogenic belt, which controls lots of molymetalic deposits, is an important Cu-Mo-Au-Pb-Zn molymetalic metallogenic belt in the China-Russia-Mongolia border area. Cu-Mo deposits, such as Wunugetushan, Badaguan, Babayi, are concentrated in Manzhouli and Chen Barag Banner. However, there is big ore-prospecting space in the area whether in number or in scale compared with Cu-Mo deposits in the Erguna-Upper Heilongjiang-Gangren metallogenic belt in adjacent Russia. On the basis of field geological work and investigation of the Badaguan deposit, the authors investigated geological characteristics of the deposit. On the basis of studying rock geochemical data (major elements, trace elements and REE), LA-ICP-MS U-Pb dating of zircon and Re-Os dating of molybdenite, the authors hold that the Badaguan Cu-Mo deposit is a porphyry Cu-Mo deposit related to orogenic belt and was formed in Late Indo-Chinese epoch(205.8±3.4Ma)and controlled by Badaguan short-axis anticlines or NE-SN faults. A comparison with the Wunugetushan Cu-Mo deposit shows that granite-porphyry generated in Early-Yanshanian period is probably a new type of ore-bearing rock in the Badaguan ore district.