Discussion on geological characteristics and genesis of iron deposits in Changzhenggou, Qinghai Province

Changzhenggou iron deposit, an important iron deposit found recently, is located in northern margin of the collision belt of Qaidam block and South Qilian block. In order to find out the deposits characters and genesis, the authors carried out the geological survey of iron deposit by geological means, and the results could provide some reference for the deployments planning of regional geology and mineral resources and mineral exploration. The results show that the main group is Tanjianshan Group with low metamorphic degree and weak epidotization in the study area. In the western part of the Heishanquan and the middle part of Zangyanggou, the strata are lentoid marble with the wide skarn petrification and few skarn-magnetite. The main alteration includes four types of skarn-type magnetite, such as diopside, epidotization, garnet petrification etc. The intrusive rocks are widely developed in the study area, where the outcrops range from basic rocks to acidic rocks. The northern part is dominated by basic intrusive rocks and the rocks transform southwards to acidic (middle) intrusive rocks. The iron deposits are the skarn type iron ore deposits related to the middle acidic intrusive rocks, and the prospecting criteria of lithology, structure, alteration and geophysical prospectin were summarized.