THE METAMORPHIC ROCK SERIES IN JINING AREA, INNER MONGOLIA: Protolith restoration and ore-prospecting guide

Jining area, situated in the eastern section of the Yinshanian mountain range in central Inner Mongolia, tectonically belongs to the Liangcheng fault uplift of Inner Mongolia anteclise on the northern margin of North China platform. The basement outcrops are predominantly Archean medium-high metamorphosed rocks, which are divided by the Datucheng hidden deep fault into the Jining rock group in south and the Wulashan rock group in north. The protolith of the Jining rock group is composed of mainly argillaceous arkose, argillaceous siltstone and carbonate rock associated with basic intrusions. The protolith of the Wulashan rock group is a suite of volcanic-sedimentary formation in huge thickness, consisting of arkose, argillaceous arkose, argillaceous sandstone and argillaceous siltstone, intercalated with andesite, andesitic tuff and carbonatite. Based on four sheets of 1:50000 scale mineral survey in Jining area, the geochemistry and ore content of the metamorphic rock series are studied. It is concluded that the metamorphic rocks are the major host of ores in this area.