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为了探讨湘西李梅矿区碳酸盐岩沉积时期古环境的指示特征,对矿区外围下寒武统清虚洞组灰岩、白云岩和高台组纹层状白云岩进行了元素地球化学分析。结果表明:1)Sr与Ca O,Si、Al、K和Fe,Si、Al、K、V和Ti相互之间具有密切相关性,反映了清虚洞期到高台期碳酸盐岩沉积受陆源物质和成岩作用的影响有限。2)碳酸盐岩中∑REE含量较低,稀土元素分异程度较弱,轻稀土元素相对重稀土元素呈轻微富集特征,符合海相碳酸盐岩稀土含量较低的典型特征。3)研究区岩石学特征和元素地球化学特征所反映的沉积环境相一致性,对岩石地球化学特征的研究有益于古沉积环境恢复和古气候的判别与重建。岩石学和地球化学特征指示了研究区清虚洞期到高台期海相碳酸盐岩沉积环境为由潮湿到干旱的气候变化,古海水温为暖水环境,古海水介质为氧化条件的意义。
In order to discuss the paleoenvironmental characteristics of carbonate deposits during Liyan mining area in Western Hunan, the elemental geochemistry of limestone, dolomite and Gaotai stratigraphic dolostones of the Lower Cambrian Qingxudong Formation in the periphery of the mining area was studied. The results show that: 1) Sr and CaO, Si, Al, K and Fe, Si, Al, K, V and Ti are closely related to each other, reflecting the emplacement of carbonate deposits from the Qing Dynasty to the high stage The effect of terrigenous matter and diagenesis is limited. 2) The content of ΣREE in carbonate rocks is relatively low, and the degree of REE differentiation is relatively weak. The light heavy rare earth elements are slightly enriched in REE, which is in line with the typical characteristics of low REE content of marine carbonates. 3) The consistency of sedimentary environment reflected by petrology and elemental geochemistry features in the study area, and the research on geochemical characteristics of rocks is beneficial to the restoration of paleoenvironment and the discrimination and reconstruction of paleoclimate. The petrologic and geochemical characteristics indicate that the sedimentary environment of the marine carbonate from the Qing Dynasty to the high stage of the study area is from humid to arid climate, the ancient sea water temperature is warm water environment, and the ancient sea water medium is the oxidation condition.