Abstract:The Etouchang Fe-Cu deposit is one of the well-known Proterozoic copper-bearing iron deposits in central Yunnan Province. Besides Fe and Cu, rare earth elements (REEs) coexist in the deposit. In this study, the authors used the automated mineral identification and characterization system (AMICS), which is the most up-to-date mineral automatic analysis system in mineralogy and geology in the world, in combination with scanning electron microscope and X-ray energy dispersive spectrometer (SEM-EDS) microstructure in-situ analysis technique, to perform quantitative mineral identification in the Etouchang Fe-Cu deposit, and obtained the undertaking unattainable by conventional means of rock-mineral identification. The authors found for the first time independent rare earth minerals (e.g., parisite, bastnaesite and fergusonite) in the ores from the Etouchang Fe-Cu deposit. Parisites are mainly concentrated in the banded magnetite ores, mainly exist as hypidiomorphic or allotriomorphic granular texture, irregular micro fine-grained granular aggregates, and are closely associated with gangue minerals such as calcite and chlorite, which are located in the marginal fissures of magnetites. And in the parisites, there exist widely distributed bastnaesite precipitates, which are mainly tabular or columnar, lamellar and acicular in form. Fergusonites are also mainly concentrated in the banded ores coexisting mainly with chlorites, and mainly exist as small fine-grained hypidiomorphic or allotriomorphic granular particles. Energy dispersive analysis of X-rays show that parisites and bastnaesites are rich in light rare earth elements (LREEs), dominated by Ce, Nd and La, with the order of Ce > La > Nd generally. In addition, they contain a small amount of Pr and Y. Fergusonites contain many kinds of metallic elements such as Nb, Fe, Y, Ce, Nd, Ti, Mg, Ca and U, and the content of Nb in the mineral is relatively high (Nb=39.15%~45.03%), rare earth elements are mainly Y, with a small amount of Ce and Nd. The discovery of rare earth minerals in the ore has important implications for the study of the genesis of this deposit and Precambrian (Mesoproterozoic) Fe-Cu (-REE) deposits in central Yunnan Province. According to the generation characteristics of rare earth-iron oxides in the deposit and regional metallogenic geological background, combined with previous research results, the authors consider that the formation of rare earth-iron oxides of this deposit was related to the deep (mantle) magmatic activity during the breakup of the Columbia supercontinent and was reformed and superimposed by the late hydrothermal event during the Grenville orogeny and breakup of the Rodinia supercontinent.