沉积学报2025，Vol.43Issue(1)：50-62,13.DOI:10.14027/j.issn.1000-0550.2023.054
湘西北古丈地区大塘坡组锰矿沉积地球化学特征与沉积环境分析
Geochemical Characteristics and Sedimentary Environment Analysis of Manganese Ore from the Datangpo Formation in the Guzhang Area,Northwest Hunan Province
摘要
Abstract
[Objective]We analyzed the sedimentary environment of manganese ore in the Datangpo Formation of the Nanhua System in the Guzhang area,northwest Hunan province.[Methods]Based on the geochemical analysis of major and trace elements,rare earth elements and carbon and oxygen isotopes,the oxidation-reduction environment and the source of ore-forming materials during the deposition of manganese ore in the Datangpo Formation were stud-ied.[Results](1)There is a positive correlation between SiO2,TiO2,K2O,and Al2O3,weak negative correlation with MgO and CaO,and weak correlation with MnO,Na2O,TFe,and P2O5 for the main elements of manganese ore in the Guzhang area.The deposit is similar to the Gucheng manganese ore in Hubei,Xiangtan manganese ore in Hu-nan,and Zhaodong manganese ore in Hunan,with an overall high Si,low Fe,and P-bearing manganese ore.(2)The redox-sensitive elemental indicators,Fe/Mn＜1,2＜V/Cr＜4.5,V/(V+Ni)＞0.57,Ni/Co＜5,and U/Th＜0.75,of the depositional environment indicate that the water column was in a normoxic-poor environment when the manga-nese ore was formed in the Datangpo Formation.The enrichment pattern of the medium rare earth elements,depletion of light and heavy rare earth elements,and the weak positive Ce anomaly indicate that Mn was first precipitated in the form of manganese oxides or hydroxides and then changed into Mn carbonate during digenesis.(3)A variety of metal-logenic material source identification indicators,SiO2/Al2O3＞3.6,Y/Ho close to that of the hydrothermal fluid on the seafloor,results of Fe-Mn-(Ni+Cu+Co)×10 triangulation,and Co/Zn-(Cu+Ni+Co)diagrammatic show that the for-mation of Mn elements from the manganese ores in the Datangpo Formation in the Guzhang area is closely related to submarine hydrothermal action and has characteristics of hot-water deposition.[Conclusions]The manganese ore of the Datangpo Formation was formed in a normoxic-poor environment in the Guzhang area,northwest Hunan province.The formation of manganese is closely related to submarine hydrothermal action.关键词
大塘坡组/古丈地区/地球化学/沉积环境/热水沉积Key words
Datangpo Formation/Guzhang area/geochemistry/sedimentary environment/hydrothermal sediment分类
天文与地球科学引用本文复制引用
付文念,李凤杰..湘西北古丈地区大塘坡组锰矿沉积地球化学特征与沉积环境分析[J].沉积学报,2025,43(1):50-62,13.基金项目
中国地质调查局公益性基础地质调查项目(DD20160032)[Program of Non-profit and Basic geological Survey,No.DD2016 0032] （DD20160032）
