Sedimentary Facies Analysis Of Datangpo Type Manganese Deposit In Northeast Guizhou

This survery from the perspective of geology research,on the basis of field outcrops,brick core hole,the microscopic chip data,geochemical samples and detrital zircon,collecting and sorting the results of other researchers,using sequence stratigraphy,sedimentology,geochemistry,such as the scientific method.The regional stratigraphic correlation of Nanhua series strata in northeast Guizhou was carried out,and the sedimentary facies characteristics,distribution rules and manganese ore concentrated facies belt in the first section of Datangpo formation were analyzed.The core was to determine the sedimentary facies model in the first section of Datangpo formation,so as to provide geological basis for the distribution prediction and exploration and development of "Datangpo type" manganese deposits in northeast Guizhou.(1)Stratigraphic division and correlation of the south China series in northeast Guizhou,based on the data of rock assemblage characteristics,sedimentary structure and regional strata in northeast Guizhou,the Nanhua formation is divided into four strata from old to new: Liangjiehe formation,Tiesiao formation,Datangpo formation and Nantuo formation.The Datangpo formation is divided into upper and lower sections.Based on the study of detrital zircon U-Pb chronology,the Nanhua series strata were divided into two glacial periods and two interglacial periods.The Liangjiehe formation are interglacial deposits corresponding to the middle and upper part of Fulu formation.Tiesiao formation is a record of glacial period corresponding to Gucheng glacial period.The Datangpo formation is an interglacial transgressive record corresponding to the black shale at the top of Fulu formation.The Nantuo formation was deposited during the glacial period,corresponding to the Marinoan glacial period.(2)At the same time of establishing the early sedimentary and filling sequence of Datangpo of Nanhua period in northeast Guizhou,The sedimentary basins in this area were divided into 4 class II basins,12 class III basins and 11 manganese accumulationbasins.Fourteen types of lithofacies have been identified in Datangpo section of different basins.It is proposed that under the background of continental margin rift basin,the early sedimentary environment of the Datangpo of Nanhua period in the study area belongs to the continental marginal barrier coastal system,the typical "Datangpo" manganese ore is closely related to the deep water confined basin with rapid settlement behind the barrier.(3)Based on the geochemical analysis of the samples of Datangpo formation in the northeastern guizhou manganese ore area,the manganese may come from the deep ocean crust,and the land source material supply is very small.The paleoclimate environment formed generally showed a trend of cold and dry-relatively stable-gradually heating up after the little ice age.Taking into account the geological and geochemical conditions of the Datangpo of the Nanhua period in northeast Guizhou,the manganese forming environment of the Datangpo type manganese deposit is the continental margin barrier coastal environment under the extensional background after the glacial period.