The Geological Features And Genesis Discussion Of Gaotaigou Boron Deposit In Jian City, Jilin Province

Gaotaigou boron deposit is located in Ji'an City,Jilin Province.The geotectonic location is the Paleoproterozoic structural area in the south of Liaoning and Jilin Province,with Longgang block in the north and Langlin block in the south.The strata exposed in the mining area are mainly the Mayihe formation of Ji'an group of Paleoproterozoic.The structures in the mining area are mainly fold and fault structures,with weak magmatic activity.The ore body is strictly controlled by the stratum and occurs in serpentine marble of the Mayihe formation of Ji'an group.Its shape is mainly layered,stratoid and lenticular,and its occurrence is consistent with the stratum.The intermittent distribution range is 1055m long from north to south,760m wide from east to west.The ore type is brucite serpentine type and brucite magnetite serpentine type.The main ore minerals are brucite and brucite,the main gangue minerals are serpentine and calcite,followed by olivine,magnesite,dolomite and magnetite,and a small amount of plagioclase and phlogopite.The ore structure mainly consists of metamorphic structure,automorphic semi automorphic granular structure,allomorphic granular structure,rotational cataractous structure and recrystallization structure;the ore structure mainly consists of disseminated structure,banded structure,agglomerated structure,breccia structure,striated structure and spotted structure.In this study,siliceous rocks are found in the mining area.The temperature measurement of the fluid inclusions in the siliceous rocks in the Gaotaigou boron deposit shows that the fluid inclusions in the siliceous rocks have the char acteristics of high temperature?308?³22??,medium low salinity?10.2wt%¹2.0wt%?,low density?0.80g/cm³⁰.85g/cm³?.The estimated metallogenic pressure is 11-19mpa,and the depth of paleoseawater is 1.1-1.9km.Stable isotope study shows that?¹¹B value?8.69%¹2.32%?of boron isotope of boron ore indicates that ore-forming materials are from oceanic crust and ore-forming fluids are from circulating seawater.Combined with the fact that the Gaotaigou boron deposit is mainly controlled by the strata,the host rock is mainly serpentinized marble,which has obvious stratabound characteristics.The analysis of the major element geochemical data of the host rock in the mining area shows that it is mainly used for hot water in the sedimentary process.Based on the above analysis,it is considered that the Gaotaigou boron deposit is a hot water jet sedimentary boron deposit and has experienced later metamorphism and deformation.