地质学报2024，Vol.98Issue(8)：2299-2315,17.DOI:10.19762/j.cnki.dizhixuebao.2024191
准格尔煤田老三沟外围勘查区煤系Al-Ga-Li-Nb(Ta)-Zr(Hf)共富集成因及资源潜力评价
The co-enrichment mechanism and resource potential of Al-Ga-Li-Nb(Ta)-Zr(Hf) in Laosangou coal exploration area,Jungar coalfield
摘要
Abstract
The Permo-Carboniferous coal-bearing sequences of the Jungar coalfield,Inner Mongolia,exhibit significant enrichment of strategic metals,including Al,Ga,Li,and rare earth elements. This study investigates the enrichment mechanism of Al-Ga-Li-Nb (Ta)-Zr (Hf) strategic metal assemblages in these coal-bearing sequences,focusing on the Permo-Carboniferous coal-bearing sequence from the Laosangou peripheral exploration area. Systematic mineralogical and trace element geochemical analyses were employed,encompassing optical microscopy,X-ray diffraction (XRD),scanning electron microscope with energy dispersive spectroscopy (SEM-EDS),X-ray fluorescence spectrometer (XRF),a TIMA-X comprehensive mineral analyzer based on a Tescan Mira scanning electron microscope,and inductively coupled plasma-mass spectrometer (ICP-MS). The Taiyuan and Shanxi Formation coals in the Laosangou area display co-enrichment of Al-Li-Ga and Nb-Ta-Zr-Hf assemblages. In particular,concentrations of Li,Ga,and Zr in the entire coal seam,and those of Nb and Ta in specific sections of the main recoverable No.6 coal seam,reach levels that meet industrial utilization grades. This suggests significant metallogenic potential and value for development and utilization. The enriched Li and Ga in the coal exhibit a clear affinity for aluminosilicates,predominantly occurring in kaolinite and boehmite,and Li may also occur in chlorite. The enrichment of Al,Ga,and Li in the Taiyuan and Shanxi Formation coal-bearing sequence is a consequence of a complex interplay of geological processes. Firstly,weathering and denudation of Mesoproterozoic moyite in the Yinshan Oldland provide a primary source for Al,Ga,and Li enrichment. Terrigenous detritus derived from this source was initially enriched in the weathering crust of the Upper Carboniferous Benxi Formation,located in the northeastern part of the basin,serving as a direct material source of Al,Ga,and Li enrichment in the coal-bearing sequences. Secondly,fluid activity and water/rock interactions played a crucial role. Al,Ga and Li migrated along with groundwater and were subsequently deposited and enriched in the coal-bearing sequence. Lastly,the input of Li,Ga,Nb and Ta-rich intermediate-felsic alkaline volcanic ash,coupled with the migration of hydrothermal fluids,led to secondary enrichment of these elements in the studied coals during the coalification process.关键词
煤系铝-镓-锂/富集成因/铝土质风化壳/火山灰/流体迁移/准格尔煤田Key words
Al-Ga-Li in coal-bearing sequence/enrichment mechanism/bauxitic weathering crust/volcanic ash/fluid migration/Jungar coalfield引用本文复制引用
李晶,李文华,庄新国,王道华,张涵,冯向东,袁伟,张晓阳,王园,郭帅,蔡洪广..准格尔煤田老三沟外围勘查区煤系Al-Ga-Li-Nb(Ta)-Zr(Hf)共富集成因及资源潜力评价[J].地质学报,2024,98(8):2299-2315,17.基金项目
本文为国家重点研发计划项目(编号2021YFC2902000)、国家自然科学基金项目(编号42372199)、第三次新疆科考项目(编号2023xjkk0100)和新疆重大科技专项(编号2022A03014-2)联合资助的成果. （编号2021YFC2902000）
