Abstract: The Sankuanggou skarn Fe-Cu deposit is located in the Duobaoshan metallogenic belt of the northern Greater Khingan Range, Heilongjiang Province. The ore bodies occur in the garnet skarns of the contact zones between the Yanshanian granodiorite and the Ordovician Duobaoshan Formation marble. As indicated by mineral assemblage and interaction, the hydrothermal ore-forming process included the prograde skarn, retrograde skarn and quartzsulfide stages. Iron oxides and copper sulfides were mainly formed in the retrograde skarn and quartzsulfide stages, respectively. Electron microprobe analysis showed that garnets are made of andradite and grossularite; pyroxenes consist of diopside and hedenbergite; amphiboles belong to calciferous amphibole; chlorites are trioctahedral Fe-chlorite; and the mineral assemblage in the Sankuanggou Fe-Cu deposit is a typical calcareous skarn system. Garnets present as early coarse-grained grossularite (Grt-Ia) and andradite (Grt-Ib), and late fine-grained andradite veins (Grt-Ⅱ). Skarns formed under high temperature and weak acidic and oxidizing conditions. Retrograde skarnization led to  decreased temperature and higher pH resulting in magnetite and specularite deposit, while chalcopyrite and other sulfides precipitated due to decreased oxygen fugacity and temperature following retrograde skarnization.

Key words: physicochemical conditions, mineralogy, Sankuanggou skarn Fe-Cu deposit, Great Hingan Range, Heilongjiang Province