Characteristic of REE of Hongyuntan Iron Deposit in the Eastern Tianshan of Xinjiang and Its Genetic Significance

Hongyuntan iron deposit in the eastern Tianshan of Xinjiang is hosted in volcanic-sedimentary series of the Lower Carboniferous Yamansu Formation.The ore bodies occur as layered,stratiform-like or lenticular,and are mainly controlled by NE-and NNE-trending compresso-shear thrust faults.The metallogenic periods including skarn,hydrothermal and supergene were recognized,and were further divided into four metallogenic stages including anhydrous skarn,degenerate alteration(principal metallogenic stage),early hydrothermal and quartz-sulfide.Characteristics of REE of rock and mineral showed that chondrite-normalized REE pattern of garnet during the skarn period was polygonal line shape with obvious Eu positive anomaly,the genetic characteristic was magmatic hydrothermal,and the characteristic of REE of magnetite during the principal metallogenic stage was homogenous with that of garnet.Magnetite and pyrite during the hydrothermal period showed obvious Eu negative anomaly and weak Ce negative anomaly,so that Eu-rich ore-forming fluid developed skarn and iron ore body in the high temperature and oxidation environment during the skarn period,and gradually developed vein and disseminated iron mineralizer and sulfide in the low temperature and reduction environment during the hydrothermal period.Characteristics of metallogenic geology and REE of rock and mineral indicated that Hongyuntan iron deposit was the skarnized product with magmatic hydrothermal genesis.