Research On Ore-forming Fluids And Deposit Genesis Of Huayangchuan Uranium Polymetallic Deposit In Shanxi Province

The Huayangchuan uranium polymetallic deposit in Shanxi is a carbonate-type vein-shaped uranium polymetallic deposit newly discovered in the Xiaoqinling area on the southern margin of the North China Block in recent years.In order to ascertain the nature of the ore-forming fluid,the source of ore-forming material and the ore-forming mechanism of the Huayangchuan uranium polymetallic deposit,systematic petrographic observations,fluid inclusion studies,and C-O,H-O,Pb and S isotopic analysis were carried out.Some conclusions and achievements have been obtained as follows:Through detailed petrographic observations,analysis of vein interspersed relationships and ore mineral composition and structure,the hydrothermal ore-forming process of Huayangchuan uranium-niobium-lead deposit is divided into quartz-potassium feldspar stage,carbonate stage,and sulfide stage.And zeolite stage.Among them,the carbonate stage is the main mineralization stage of uranium deposits,and the sulfide stage is the main mineralization stage of lead deposits.The H-O isotopic composition of the Huayangchuan deposit indicates that the ore-forming fluids in Huayangchuan are dominated by mantle-derived fluids.The ore-forming fluid in the first stage of Huayangchuan uranium polymetallic deposit has characteristics of medium temperature,rich in CO₂,and low salinity;the second stage of ore-forming fluid has characteristics of medium and low temperature and low salinity;the third stage of mineralization The fluid is mainly an aqueous solution,which is a low temperature,CO₂ lean fluid.Laser Raman analysis shows that the type of ore-forming fluid is CO₂-H₂O+SO₄^2--Na Cl.The sulfur,lead and carbon-oxygen isotopic compositions of the Huayangchuan deposit indicate that the ore-forming materials of the Huayangchuan uranium polymetallic deposit are mainly derived from the mantle.The Mineralization age of Huayangchuan uranium polymetallic deposit is Late Triassic.Under the background of extensional tectonics,the asthenosphere upwelled due to the separation of the subducting plates,which heated the enriched lithospheric mantle,resulting in a low level of the enriched lithospheric mantle.The degree of partial melting forms carbonate magma,which rises along the weak structural zone to the upper crust,where fluid dissolution occurs,and deposits and deposits are enriched in the NW Huayangchuan fault zone.