Cu-source and enrichment laws of the Duobaoshan porphyry copper deposit in Heilongjiang province
Liu Yang1, Cheng Xuezhan1, Wang Xichen2, Liu Jinying3, Wang Lin1, Wang Xunlian1
1. China University of Geosciences, Beijing 100083; 2. Management Centre of Central Geological Exploration Fund, Ministry of Land and Resources, Beijing 100045; 3. Beijing Exploration and Technique Engineering Corp.Ltd., Beijing 100080
The Duobaoshan porphyry copper deposit in NW Heilongjiang province is situated in eastern sector of the Xing’anling-Mongolian (for short,Xing-Meng) orogen.The regional tectonic evolution in Early Paleozoic was constrained by east (to north) ward subduction of the Xing-Meng ocean under the Burean-Jiamusi Block,and the Middle Ordovician volcanic arc was NW-striking.The tectonic evolution in Late Paleozoic was controlled by northwestward subduction of the Xing-Meng ocean under the Kerlen-Ergun Block,with the structural line (the Devonian rifting and Permian magmatic arc) being NE-striking.The Cu-source in Duobaoshan area might be of multiple origin,with the main source layer being the Middle Ordovician arc-volcanic rocks,and the minor source one being the Early Devonian rift volcanics.Although the Middle Hercynian granodiorite and granodioritic porphyry might support a part of mineral source,its main contribution to the mineralization could be concluded that the pulsating hydrothermal activities were dynamics for migration and enrichment of copper in a high background.The copper was absorbed from the wallrocks enriched and emplaced in the surrounding positions of the porphyries,and meanwhile some cu-descended positions appeared in the mining and adjacent areas.The metallogenic epoch of the Duobaoshan porphyry copper deposit was Middle Hercynian,when three stages of hydrothermal activity accompanied the Late Carboniferous volcanism,the intrusions of granodiorite and granodioritic porphyry respectively.The copper or copper-polymetallic ores of other types formed in the Late Hercynian-Indosinian and Yanshanian tectono-thermal events,and the Duobaoshan porphyry copper deposit was reformed in these later orogenies.