地质学报2024，Vol.98Issue(8)：2395-2408,14.DOI:10.19762/j.cnki.dizhixuebao.2024130
晋南地区煤系黏土岩中锂的赋存状态及其沉积环境
Lithium occurrence state and sedimentary environment of clay rocks in coal-bearing strata in southern Shanxi
摘要
Abstract
The strategic importance of key metals,such as lithium,and their implications for national security are gaining prominence in the contemporary geopolitical landscape. The North China Craton,with its abundant lithium-rich clay rock resources,represents a significant exploration target for sedimentary lithium deposits in China. This article focuses on the clay rocks in coal-bearing strata in the southern Shanxi area of the North China Craton. A comprehensive suite of characterization techniques,including X-ray powder diffraction (XRD),X-ray fluorescence spectroscopy (XRF),inductively coupled plasma-mass spectrometry (ICP-MS),Fourier transform infrared spectroscopy (FTIR),and magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR),was employed to investigate the lithium distribution and sedimentary environment of Benxi Formation clay rocks. These techniques are complemented by chemical phase analysis and clay mineral flotation experiments. Results demonstrate that clay minerals are the main carriers of lithium,including Li-chlorite,illite,and kaolinite. A strong positive correlation exists between lithium content and Li-chlorite content,while weaker positive correlations are observed with illite and kaolinite content. Lithium in samples mainly exists in the octahedral lattice of interlayer hydroxide sheets in Li-chlorite,with lesser amounts occurring in illite and kaolinite. Paleoenvironmental indicators,including salinity proxies[m(100×(MgO/Al2O3)) and 1000×Rb/K2O values]and redox proxies[V/(V+Ni) and Th/U values],suggest that the lithium-rich clay rocks formed in a freshwater to brackish water environment,characterized by anoxic and oxygen-poor conditions. Geochemical proxies,including Sr/Cu,C ((V+Cr+Mn+Fe+Co+Ni)/(Na+Mg+K+Ca+Sr+Ba)),and CIA values,indicate a hot and humid paleoclimate during their formation. This study contributes to a better understanding of the formation processes of sedimentary lithium deposits and provides valuable insights for developing efficient separation and extraction techniques of this type of lithium resource.关键词
锂/赋存状态/煤系黏土岩/沉积环境/晋南地区Key words
lithium/occurrence state/clay rocks in coal-bearing strata/sedimentary environment/southern Shanxi引用本文复制引用
程宏飞,武振晓..晋南地区煤系黏土岩中锂的赋存状态及其沉积环境[J].地质学报,2024,98(8):2395-2408,14.基金项目
本文为国家自然科学基金项目(编号42172043)和中央高校基本科研业务费专项资金(编号300102263301)联合资助的成果. （编号42172043）
