Formation mechanism of Gongchangling high-grade magnetite deposit hosted in Archean BIF,Anshan-Benxi area,Northeastern China |
| |
| Institution: | 1. Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;2. University of Chinese Academy of Sciences, Beijing 100049, China;3. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangdong, Guangzhou 510640, China;1. Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;2. Institute of Mineral Resources Research, China Metallurgical Geology Bureau, Beijing 100025, China;1. CAS Key Laboratory of Crust–Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;2. School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, Republic of Korea;3. No. 313 Geological Team, Bureau of Geology and Exploration of Anhui, Liu''an 236000, China;4. Key Laboratory for Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China |
| |
| Abstract: | Banded iron-formations are main resources of global iron ore in which high-grade ore is mainly composed of martite–goethite and hematite. They are also the major resource of iron ore in China, mainly distributing in Liaoning and Hebei Province. In China, the iron ore with Fe greater than 50% is classified as high-grade iron ore. The high-grade iron ore mainly consists of magnetite and displays its unique characteristics. Gongchangling iron deposit is one typical BIF-iron deposit which contains 150 Mt of high-grade iron ore in China. The high-grade magnetite ore bodies mainly occur around magnetite quartzite, faults and the cores of folds and show positive relation to the development of the “altered rocks” in this deposit. This research shows that high-grade magnetite comes from magnetite quartzite and they are both formed, with little or no addition of aluminum-containing detrital material, by marine chemical deposition in reduced environment and they are closely related to seafloor hydrothermal activity.Muddy–silty rocks are original rocks of “altered rocks”, of which the primitive mantle normalized REE pattern, except Eu, is consistent with that of iron ore, reflecting that their formation is related to the formation of high-grade magnetite ore. Therefore, the formation mechanism of high-grade iron ore is proposed as following: the regional metamorphism provides storage space for the formation of high-grade magnetite ore and required temperature and pressure conditions for the mineral transformation; the regional metamorphic hydrothermal fluid leaches FeO out of magnetite quartzite when it passes by; and the FeO that leached out moves near faults or cores of folds together with the metamorphic hydrothermal fluid and aluminum-containing rocks, of which the original rocks are muddy–silty; in the formation of high-grade iron ore, aluminum-containing rock appears in the intervals of sedimentation of iron-containing rock series and consumes the silicon leached out of magnetite quartzite and forms garnet, chlorite, and biotite. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
