THE GENESIS OF COPPER-IRON POLYMETALLIC ORE DEPOSITS IN THE CARBONIFEROUS IN SOUTHERN ANHUI PROVINCE

Copper-iron and polymetallic ore deposits occurring in the Carboniferous of southern Anhui are an important component part of the middle and lower Yangtze River valley copper-ijon metallogenic belt of China. Divergent views have long existed as to the genesis of this type of deposit. In recent years the author has made an in-depth analysis and study of the genesis of the deposit in this study on the special subject in the area, and has gained some new knowledge. The author holds that this type of deposit occurs in a persistent horizon and is mainly localized between sandstone-shale of the upper part of the late Yanguanian （Carboniferous） Leigutai Member and dolomite of the early Weiningian Laohudong Formation, controlled by the tidal flat-evaporite platform sedimentary facies of this period. Orebodies are mainly stratiform in shape, generally 25—40m thick and 3—4km long along the strike, and exhibit distinct features of sedimentary origin. Studies of the ore types, mineral composition, textures and structures, chemical composition, trace elements and sulfur isotopes of this type of deposit also indicate that the formation of the deposits hadgone through a process of deposition （ore and rock-forming processes）—structural disturbance （including metamorphism）—-hydrothermal superimposition and reworking. Therefore, the deposits should belong to sedimentary-hydrothermal reworking stratabound deposits.