Abstract: Petrochemical and geochemical data indicate that ophiolitic melanges in the Middle Late Proterozoic Kaiyuan Group complex are composed of ophiolite, island arc tholeiite, calc alkaline basalt （amphibolite and hornblendite）, calc alkaline basic intermediate volcanic rocks （granulitite） and continental margin clastic rocks （leucogranulitite）. Of them ophiolite consists of chlorite talc schist （peridotite）, amphibolitic rocks （oceanic tholeiite） and quartzite （pelagic cherts）. They are located together with ophiolite of the Ondor Sum Group of Inner Mongolia and the Seluohe Group of Jilin on the northern margin of the North China paleocontinental block .