Abstract: Longgou manganese deposit is located in Dounan metallogenic belt,that is the high-quality manganese ore belt in the southeast Yuannan province.The ore-bodies are located in the middle Triassic Falang formation,they are exposed with layered and lenticular shapes,which is similar with the occurrence of surrounding rock.The ore-bearing rocks are mudstone,silty mudstone interbedded with conglomeratic sandstone,fine sandstone and siliceous rocks.The sedimentary environment is littoral-neritic facies.Based on the geological working results of the mining area,the regional geological background,geological characteristics of the mining area,geological characteristics of the deposits are analyzed,and the source of manganese,sedimentary environment are discussed,the results show that the genetic type of the deposit is the littoral-neritic facies manganese deposit that is suffered the secondary oxidation transformation.The above analysis result can provide some reference for the further prospecting work of manganese deposit in the mining area.

Key words: Manganese deposit, Regional geological background, Geological characteristics, Sedimentary environment, Deposit genesis