Mineralization Pattern of the Yeniutan Ore field,Gansu Province

Since the 1960s, many deposits such as Taergou W deposit, Qinghe Fe deposit, Renganggou Fe deposit and Shidonggou polymetal deposit were successively found in the Yeniutan area of Gansu Province, and all the deposits constitute the so-called Yeniutan ore field. Beginning with the geological background of the ore field, this study analyzed the geological characters of each deposit and rock and summarized the metallogenic models of the Yeniutan ore filed in combination with ore-controlling factors, mineralization, genetic types and material origins. The results show that each deposit is controlled mainly by ore-forming factors such as rock, sequence and faulting, with the Yeniutan rock as the dominant engine and dynamic force of mineralization. The formation of the Yeniutan ore field consists of two periods. The first period witnessed Paleoproterozoic rifting environment and Eopaleozoic plate active margin environment, in which two volcano-sedimentary metallogenesis resulted in the formation of ore source layers and ore local enrichment in the ore field. The second period is Late Ordovician, in which the ore field in island-arc setting was intruded by crust-melting magma (459.6~441.97Ma). Under such magmatism, early hydrothermally-altered mineralization and late crystal-filling mineralization took place in the contact zone. Therefore, the second period is the main stage for the formation of the ore filed as well as each deposit.