Discussion on Genetic Types and Prospecting Markers of Graphite Deposits in Ulan Area of Inner Mongolia

On the basis of field investigation, this paper used ¹³C isotope analysis and differential thermal analysis to determine the metallogenic conditions and genetic types of Wulan crystalline graphite ore in the northern margin of Craton in North China.The average content of graphene ¹³C is-27.17 ‰,slightly higher than that of the organic matter 13C (-26‰).The maximum exothermal peak of graphite is 726-1 030℃,mainly between 900-1 030℃, showing that the metamorphism of the graphite ore was amphibolite facies and granulite facies.The carbon was from homologous biological organic matter.The characteristic of the deposit and that of mineral combinations deduced that the mineral-bearing structure of graphite ore was a set of typical high-temperature metamorphic aluminium-rich sedimentary rocks. The organic deposits were decomposed and recrystallized by regional metamorphism,forming graphite source beds.The heat source provided by the Hualixi intrusive body increased the flake of the graphite, thus graphite ore enriched and formed at later stage because of ductile shear.