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    汤家辉, 董国臣. 内蒙古清水河木纹石特征及其形成机制[J]. 中国地质, 2021, 48(3): 872-882. DOI: 10.12029/gc20210315
    引用本文: 汤家辉, 董国臣. 内蒙古清水河木纹石特征及其形成机制[J]. 中国地质, 2021, 48(3): 872-882. DOI: 10.12029/gc20210315
    TANG Jiahui, DONG Guochen. The feature and forming mechanism of wood-like stone in Qingshuihe of Inner Mongolia, China[J]. GEOLOGY IN CHINA, 2021, 48(3): 872-882. DOI: 10.12029/gc20210315
    Citation: TANG Jiahui, DONG Guochen. The feature and forming mechanism of wood-like stone in Qingshuihe of Inner Mongolia, China[J]. GEOLOGY IN CHINA, 2021, 48(3): 872-882. DOI: 10.12029/gc20210315

    内蒙古清水河木纹石特征及其形成机制

    The feature and forming mechanism of wood-like stone in Qingshuihe of Inner Mongolia, China

    • 摘要: 内蒙古呼和浩特南部的“木纹石”为碳酸盐岩,其质地细腻致密,具有木纹般纹饰,由红色环带及黄色环带构成。本文在野外调研的基础上,针对岩石及其红色和黄色环带进行了矿物学、岩石地球化学分析,并利用扫描电镜对元素的分布进行测试。研究表明,木纹石由中—细晶白云石组成,胶结物以泥质绢云母、钾长石和黏土矿物为主,含少量稀土矿物、钛铁矿、黄铁矿和褐铁矿等金属矿物。岩石化学和地球化学分析发现,红色环带较黄色环带富Al2O3、K2O、Fe2O3、Sr,特别是Fe元素,以线扫描中Fe的计数频率(cps)350作为标准可以很好的区分红黄条带。据Yb/(Ca+Mg)-Yb/La图解分析显示出岩石受热水活动迹象,表明海相碳酸盐岩在成岩后期演化过程中,地下(热)水沿裂隙进行渗透淋滤,由于温度差异,Fe氧化程度差异,致色因素三价Fe含量不同,使得岩石具有红-黄相间条纹特征,形成以裂隙为边界状如树木纹饰的环形环带。

       

      Abstract: Wood grown rings,named as wood-like stone,are developed in carbonatites in Hohhot,Inner Mongolia. The wood-like stone,looking like wood grown rings,is very fine grained,smooth surface with red and pale yellow ring surroundings. Based on field investigation,the mineralogy and petro-geochemistry of the wood-like stone were studied for colorful rings,and the distribution of elements was tested by SEM. The results indicate that the wood-like stone consists of mediate to fine grained dolomite with argillaceous cement. The cement is mainly composed of sericite,K-feldspar,clay minerals and a few ilmenite,pyrite,limonite and REE minerals. Chemically,Al2O3,K2O and Fe2O3 are richer in red ring than that in pale yellow one. Especially for the Fe element,the cps of Fe about 350 in the line scan can be used as the standard to distinguish the stripes of different colors. According to the graphical analysis of Yb/(Ca+Mg)-Yb/La,the rocks show signs of hot water activity. It is indicated that the marine carbonatite was infiltrated by hot fluids flowing through fractures after deposition. Due to the difference of temperature,Fe oxidation difference and the different content of trivalent Fe resulted in red-yellow stripe,forming the ring belt with cracks as the boundary like the tree ornamentation.

       

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