摘要
为恢复小保当煤矿新近系保德组沉积古环境,采用地球化学方法对小保当煤矿新近系保德组红土层古气候、古盐度、古氧化还原、古水深等进行沉积古环境研究.结果表明:小保当煤矿保德组修正后的CIAcorr指数、Al2O3/MgO值、MgO/CaO值、CaO/(MgO·Al2O3)值及Sr/Cu值和Rb/Sr值指示温暖、湿润的中等风化条件,呈干旱-湿润、寒冷-温暖交替变化;Sr、Li、Ga、Rb/K2O反映保德组为淡水-微咸水沉积环境;Fe2+/Fe3+、Ni/Co、V/Cr、V/(V+Ni)、δU、δCe和Cu/Zn反映保德组为氧化环境,局部指示贫氧环境;Co含量反映保德组古水深呈深浅交替变化.研究为小保当煤矿保德组恢复了沉积古环境,也为其他层位、其他地区古环境恢复提供依据.
Abstract
In order to restore the sedimentary paleoenvironment of Neogene Baode Formation in Xi-aobaodang Coal Mine,the paleoclimate,paleosalinity,paleoredox and water depth of the red soil layer of Neogene Baode Formation in Xiaobaodang Coal Mine were studied by geochemical methods.The re-sults show that the modified CIAcorr index,Al2O3/MgO,MgO/CaO,CaO/(MgO·Al2O3),Sr/Cu and Rb/Sr value of Baode Formation in Xiabaodang Coal Mine indicate the moderate weathering conditions of warm and wet,with alternating changes of drought-wet and cold-warm.Sr,Li,Ga,Rb/K2O indicate that the sedimentary environment of Baode Formation is fresh-brackish water.Fe2+/Fe3+,Ni/Co,V/Cr,V/(V+Ni),δU,δCe and Cu/Zn indicate that Baode formation is oxidizing environment and local oxygen-poor environment.The content of Co indicates that the paleo-water depth of Baode Formation is alternately deep and shallow.The study can restore the sedimentary paleoenvironment of Baode Forma-tion in Xiabaodang Coal Mine,and provide the basis for the paleoenvironment restoration of other strata and other areas.
基金项目
国家自然科学基金(41641018)
西安科技大学博士研究启动项目(2020DQJ02)
维普
万方数据