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| 镇江下蜀土中的黏土矿物及其古环境意义 | |
| 引用本文： | 师育新,张卫国,戴雪荣,宋之光,俞立中,郑祥民.镇江下蜀土中的黏土矿物及其古环境意义[J].海洋地质与第四纪地质,2005,25(4):99-105. |
| 作者姓名： | 师育新 张卫国 戴雪荣 宋之光 俞立中 郑祥民 |
| 作者单位： | 1. 中国科学院,广州地球化学研究所,有机地球化学国家重点实验室,广州,510640;华东师范大学,地理系,上海,200062;中国科学院,研究生院,北京100049 2. 华东师范大学,河口海岸国家重点实验室,上海,200062 3. 华东师范大学,地理系,上海,200062 4. 中国科学院,广州地球化学研究所,有机地球化学国家重点实验室,广州,510640 |
| 基金项目： | 国家自然科学青年基金项目（49201016） |
| 摘 要： | 镇江大港砖瓦厂下蜀黄土剖面30个样品的X衍射分析和半定量结果表明,该剖面黏土矿物组合为伊利石-蛭石-高岭石型,其中以伊利石（52.8%～70%）和蛭石（20.6%～38.5%）为主;古土壤层的伊利石相对含量高于黄土层,蛭石的变化与之相反,二者互为消长.高岭石含量为6.0%～11.1%,在古土壤中的含量略高于黄土层.从剖面底部（S4）至顶部（S1）, 伊利石相对含量略呈增加趋势,蛭石和高岭石则略呈减少趋势.镇江下蜀黄土中的黏土矿物组合类型与北方黄土明显不同,伊利石的结晶度总体上也较北方黄土差,反映下蜀黄土堆积区相对温暖、湿润,风化淋滤作用相对较强.从黏土矿物组合和含量来看,下蜀黄土经历了中等强度的风化作用. |
| 关 键 词： | 下蜀黄土 黏土矿物 伊利石结晶度 风尘沉积 镇江 |
| 文章编号： | 0256-1492（2005）04-0099-07 |
| 收稿时间： | 2005-02-28 |
| 修稿时间： | 2005-02-282005-05-24 |
CHARACTERISTICS OF CLAY MINERAL ASSEMBLAGE OF XIASHU LOESS AND THEIR PALEOENVIRONMENTAL SIGNIFICANCE |
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| SHI Yu-xin,ZHANG Wei-guo,DAI Xue-rong,SONG Zhi-guang,YU Li-zhong,ZHENG Xiang-min.CHARACTERISTICS OF CLAY MINERAL ASSEMBLAGE OF XIASHU LOESS AND THEIR PALEOENVIRONMENTAL SIGNIFICANCE[J].Marine Geology & Quaternary Geology,2005,25(4):99-105. | |
| Authors: | SHI Yu-xin ZHANG Wei-guo DAI Xue-rong SONG Zhi-guang YU Li-zhong ZHENG Xiang-min |
| Institution: | 1 State Key Laboratory of Organic Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences, Guangzhou 510640, China; 2 Department of Geography, East China Normal University, Shanghai 200062, China ; 3 Graduate University of Chinese Academy of Sciences, Beijing 100049,China; 4 State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200062,China |
| Abstract: | 30 samples of Xiashu loess taken from Dagang section in Zhenjiang,Jiangsu Province were analysed by the X-ray diffractemeter system.Particle-size analysis and magnetic measurements were also conducted to help explain the forming environment of the Xiashu loess.Conclusions can be drawn as follows:In Xiashu loess,the clay minerals are composed of illite(52.8%~70%),vermiculite(20.6%~38.5%),kaolinite(6.0%~11.1%) and small amount of 1.4 nm-interstratified mineral.The clay mineral assemblage,therefore,is illite-vermiculite-kaolinite pattern.The content of illite is relatively higher in paleosol than in loess,while the content of vermiculite is just the opposite.This may indicate that these two clay minerals have close relations in origin,supporting that illite can be partly formed from vermiculite during the soil development.For the whole section illite has a generally increasing trend upward,while vermiculite and kaolinite show a reverse trend.There are obvious differences in clay mineral assemblage between the Xiashu loess and the North China loess.First,the former has a higher amount of vermiculite without any of chlorite and smectite.Second,the crystallinity of illite in Xiashu loess is generally worse.They can be explained as the difference of climate between two regions,that Xiashu loess has experienced a weathering process under warmer and more humid climate than the North China loess.According to the content of kaolinite,the Xiashu loess is still in a moderate weathering in general.Furthermore,the content of illite is relatively higher in paleosol units than in loess units,while the content of vermiculite is the opposite in Dagang section.This negative relationship in content between illite and vermiculite shows that they may have close relations in origin,supporting that illite is partly formed from vermiculite during their soil development. |
| Keywords: | clay mineral crystallinity of illite eolian loess Xiashu loess |
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