Basic Study Of Wulashan Group Graphite Mineralization In The Region Of Halaganla Wusu, Inner Mongolia

The region of Halaganla Wusu in Inner Mongolia is located in the western margin of North China platform, which has been affected by the multi-stage metamorphism. It mainly developed the Medium-to High-Grade Metamorphic Rock Series of Wulashan Group in new Archean, which group mainly occurred rock of magnetite-quartzite and graphite mineralization. Various graphite mineralizations has been found in the work area, so studying graphite mineralization and its occurrence on the layer of metamorphic rock has practical significance.Based on the full collection and analysis of previous research results, relying on Large-scale mapping of litho logy in the work area, the spatial distribution, geological occurrence, rock types and mineralogy of graphite mineralization had been described and studied in detail. And it found that graphite mineralization occurs in plagioclase gneiss, biotitic-plagioclase gneiss and plagioclase dropsied gneiss of Wulashan Group. About 1 square kilometer of the central in the work area developed well, and the remaining points scattered distributed. They conformed with the entire strata direction macroscopically and displayed palimpsest strata or gneissic structure and zonal distribution. But the original bedding, contact relationship was reformed by later metamorphism and was difficult to identify by field measurements. Microscopy study found that major rock-forming minerals of the graphite mineralization occurrence layers were diopside, quartz, plagioclase and a small amount of biotite. Some specimens had garnet, rutile, sericite and chlorite. The mineralization color is silver black, and they display scaly granite metacryst, the content of graphite is 3% to 15%, which has larger size and better crystal form. It obviously can be seen that graphite cut through the other rock-forming minerals, so it can be identified that they were formed for the post of regional metamorphism.On the basis of studying of geological characteristics, specimens without alteration and mineralization have been chosen to do the chemical analysis of rock, according the results to restore the original rock by many graphics of metamorphic rock of the original rock recovery. Finally, the original rock type of the graphite mineralization is determined to sandy dolomite marl and siliceous marl in the work area. And the depositional environment of graphite mineralization in metamorphic rocks is determined to mainly a passive continental margin, applying the parameters of the chemical composition of rock.