METALLOGENY AND REFORMATION OF THE DUOBAOSHAN SUPERLARGE PORPHYRY COPPER DEPOSIT IN HEILONGJIANG
Wang Xichen1, Wang Xunlian2, Wang Lin2, Liu Jinying3, Xia Bin1, Deng Jun2, Xu Xiumei4
1. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640; 2. China University of Geosciences, Beijing 100083; 3. Shenyang Institute of Geology and Mineral Resources, China Geological Survey, Shenyang 110032; 4. Heilongjiang Bureau of Geology and Mineral Exploration and Development, Harbin 151000
The Duobaoshan porphyry copper deposit was situated in Nenjiang county, NW Heilongjiang, where outcropped the Ordovician calc-alkaline volcanic suite, indicating the copper mine an arc-related porphyry deposit formed in the Caledonian orogeny. The deposit was reformed by the Yanshanian orogeny, and two episodes of deformation could be distinguished: the early one being rejuvenation of the NEE structure in the Hercynian basement, and the second one being neo-genetic NE-striking shear zone in Early Cretaceous. The Tongshan fracture, separating the deposit into two parts, might be a representative of the Yanshanian deformation, whose early activation was normal faulting related to collapse of the Yanshanides, and the later one was thrusting southwards. As a destructive structure of postmineral period, the Tongshan fracture cut off the wall rocks, ore bodies and porphyritic mineralized alteration belts, and protected the ore bodies in the lower wall to avoid from denudation. The study on deep-seated geology and the analyses of hydrothermal alteration confirmed the existence of blind ore body in southern flank of the Tongshan fracture. To sum up, the deepened study on controlling law of metallogenic tectogenesis was a base of the effective prediction of ore deposit, and the detailed study on ore-controlling structure had a practical meaning and effect on exploration of ore deposit.