Abstract: The Ermi composite volcanic apparatus is located at the Songdingshan, the intersecting portion of an EW and NS trending crustal faults. Firstly the site was invaded by the subvolcanic rocks (diorite), then the marginal contact zones of these diorite served as the sites for the parasitical, subordinate volcanic vents, which were filled with granite stock and made up the inner circular of the composite volcanic apparatus. Though the main copper mineralization of the area is located in these granite stocks and their adjacent host rocks, the general strike and distribution of the copper mineralization in the area is controlled by the contact zones of the diorite. Combined with the regional metallogenic rules, the study on the relationship between the rock and ore formation reveals that gold mineralization is also significant besides copper ores in the area. The metallogenic model of the Ermi copper-gold ore deposit has also been set up.

Key words: volcanic apparatus, copper ore body, mineralization model, Tonghua area of Jilin