Transition from the Sedimentary Manganese Deposit to Supergene Manganese Ore in Eastern Hebei， North China: Evidences from Mineralogy and Geochemistry
作者机构：State Key Laboratory of Geological Processes and Mineral Resources， School of Earth Sciences， China University of Geosciences-Wuhan Innovation Center of Ore Resources Exploration Technology in the Region of Bedrock， Ministry of Natural Resources of People's Republic of China Hebei Institute of Geological Survey State Key Laboratory of Biogeology and Environmental Geology， School of Earth Sciences， China University of Geosciences-Wuhan Geological Exploration Technology Center of Hebei Bureau of Geology and Mineral Exploration and Development
出 版 物：《Journal of Earth Science》 (地球科学学刊)
年 卷 期：2023年
核心收录：
学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程]
基 金：the National Key R & D Program of China (No. 2022YFF0800200) the NSFC (Nos. U1812402 42072131) Most Special Fund (No. MSFGPMR33) from the State Key Laboratory of GPMR the CUG Scholar Scientific Research Funds (No. 2022036) the NSF of Hebei Province (No. D2021334001) Research Project of Talent Engineering Training of Hebei Province (No. B2020005007) Research Project of Postdoctoral Scientific Research Station of HBGMR (No. 454-0602-YBN-Z9E4)
摘 要：Original sedimentary manganese (Mn) deposits and supergene Mn ores are important Mn resources in China. However， the geochemical information from Chinese supergene Mn ores is scarce， and the relationship between sedimentary Mn deposits and supergene Mn ores is ambiguous. In this study， we collected the original Mn-bearing dolomitic sandstones (ZK20-3 drillcore) and supergene Mn ores (Longmen section) from eastern Hebei， North China for systematic petrographic， mineralogical and geochemical analyses. Our new data help us to figure out the transformation from original Mn-bearing deposits to supergene ores. The main minerals of original Mn-bearing dolomitic sandstones are quartz and feldspar， with minor muscovite， dolomite， rhodochrosite， ankerite， and kutnohorite. Supergene Mn-oxide ores only emerged in the middle part of the Longmen (LM) section， and mainly contain quartz， pyrolusite， cryptomelane， todorokite and occasional dolomite. The possible transformation sequence of Mn minerals is: kutnohorite/rhodochrosite → pyrolusite (Ⅰ) → cryptomelane (todorokite) → todorokite (cryptomelane) → pyrolusite (Ⅱ). For Mn-oxide ores， Fe， Na and Si are enriched but Al， Ca， Mg and K are depleted with the enrichment of Mn. For original and supergene ores， the total rare earth element + ytterbium (∑REY) contents range from 105.68×10-6to 250.56×10-6and from 18.08×10-6to 176.60×10-6， respectively. Original Mn ores have similar slightly LREE-enriched patterns， but the purer Mn-oxide ore shows an HREE-enriched pattern. In the middle part of the LM section， positive Ce anomalies in Mn-oxide ores indicate the precipitation of Ce-bearing minerals. It implies the existence of geochemical barriers， which changed pH and Eh values due to the long-time influence of groundwater.
同方期刊数据库