Abstract:

Duobaoshan porphyry copper deposit, located in Nenjiang, Heilongjiang Province, is one of the most important porphyry copper deposits in the North China. There are abundant mineral resources in this district, mainly including porphyry copper (molybdenum) deposit, skarn iron-copper deposit and hydrothermal gold deposit.Based on systematic analysis of the previous data, the metallogenetic regularity and prospecting direction in this district are defined. It was thought that the reactive basement structure played an important role in transportation, enrichment and dilution of the copper. The deposit types in weastern, middle and southeastern parts of the district are skarn iron-copper deposit and hydrothermal copper-molybdenum deposit, porphyry copper-molybdenum deposit as well as hydrothermal gold deposit, respectively. Caledonian porphyry copper deposit is the primary type in this district, following Hercynian and Yanshanian tectonic and magmatic process destroyed, preserved and regenerated the deposits in the district. Deposits and their occurrences are controlled strictly by the NW arc structure and hosted in the intermediate and acid volcanic rock of the Duobaoshan Formation and Tongshan Formation. There occurs a low-value copper anomaly field locates outside of the NW arc structure, with area of 228 km², such low-value copper anomaly fields are also defined in andesite around the mineralization zones, upper wall and front area of the ore bodies. Such metallogenic elements as Cu and Au are mainly provided by the country rocks. The S isotopic composition of the copper deposit shows mantle-derived features. From the early to late stage of the metallogenic process, the hydrothermal fluids changes from magmatic to meteoric water. The ore-forming fluid in Zhengguang deposit is mainly a mixture of magmatic water and natural water. It is suggested that special attention should be paid to the hydrothermal gold mineralization in Sankuanggou and Yubaoshan porphyry copper deposits. Porphyry copper deposit is the main prospecting type in Tongshan and Xiaogushan district, while in the Zhengguang district, lead-zinc mineralization is the main prospecting target.

Key words: ore district, metallogenic regularity, ore-prospecting direction, Duobaoshan