Study On The Genesis Of Stripe And Strip Like Ore In The REE-Nb-Fe Deposit Of Bayan Obo

The Bayan Obo REE-Nb-Fe deposit in Baotou City,Inner Mongolia,is the largest rare earth deposit around the world,and an important iron deposit in China.Since being reported,the ore-bearing dolomite and genesis of the Bayan Obo deposit have been highlight,and various theories have been proposed,including sedimentary hydrothermal metasomatism model,igneous carbonate model,submarine jet deposition model,microcrystalline mound model and vermiculite model.The host dolomite has been proposed to be both of sedimentary origin and an igneous carbonatite,which further increases the complexity of the Bayan Obo deposit.However,the research of the Bayan Obo deposit in recent years has mostly focused on geochemistry,and few involved in ore structure.In fact,the Bayan Obo deposit has undergone complex geological processes.Geochemical data,without regional geological setting,can't clarify the geological relationship and only make the problem more complicated in Bayan Obo deposit.There are a lot of strip-like structures of ore in Bayan Obo deposit,which is the key evidence for sedimentary origin or a igneous carbonatite of the ore-bearing dolomite.The interpretation of these band formation mechanisms may be the key to unlock the genesis of dolomite.From the ore structure,studying the ore mineral composition,structure and relationship with each other is of great significance for promoting the study of the genesis of dolomite and the genesis of rare earth deposits.On the basis of summarizing a large number of predecessors' research,the field geological survey,geostatistical method and microscopic petrography are the main research methods.The strip-like ore in the Bayan Obo mining area are taken as research objects,and the macroscopic distribution of ore strips is carried out.Regularity,rock combination characteristics,structural structure and other research content.It is found that there are three kinds of strip-shaped ores in the Bayan Obo mining area,which are stripe-shaped iron ore,strip-shaped fluorite-type rare earth ore and strip-shaped neolithic iron ore.The belt extends poorly.And there are white apatite,yellow-white dolomite,purple fluorite,black magnetite and green neon,which are completely different from sedimentary bedding and magma streamline or flow surface,in the strip-shaped ores.A statistical t-test confirms the possibility that the ore band is formed by sedimentation or magma.Combined with the geological tectonic background,it is believed that the dolomite in the mining area is broken under the tectonic stress,and the hydrothermal action in the later stage forms the fluorite,apatite and sodium amphibole in the dolomite fissure through the replacement and filling.With the deepening of the structural shearing action,the original fragmented dolomite and the hydrothermal minerals at the edges are continuously stretched and parallelized,forming stripe and strip structures of different scales.