图门江下游沙丘粒度分布与石英表面结构研究

The Character of Grain Size Analysis and Quartz Surface Texture of Sand Dunes in the Dowenriver of Tumen River

图门江下游沙丘粒度频率累积曲线形态全部为双峰 ,负偏态 ,粒度变化范围大 ,平均粒度数值小 ,标准偏差平均值为 0 .6 1 ;粒度分布特征方法判断沙丘沉积环境以河流成因为主。通过扫描电镜研究其石英颗粒表面结构 ,机械作用以贝壳状断口、V形坑和次棱角状形态组合为主 ,化学作用为中等—强烈溶蚀特征 ;石英颗粒表面结构特征表明沙丘为河口沉积 ;热释光测年结果表明沙丘受全新世海平面变化的影响 ,经历海水及风力改造。

Through the grain size analysis of sand dunes in the lower reach of the Tumen River, it is found that the frequency cumulative distribution curves are the double peak and the Sk i of the grains are negative,moreover, the change of the grain size is great and the mean value of the standard deviation is 0.64Ф,the sedimentary environment of dunes by the grain size analysis is neriticenvironment; With the analysis of Transmission Eletronic Microscopy (TEM), the shape of the quartz grains are subangular and the principaltraces of mechanical action which underwent are conchoidal breakages and V-shaped percussion pit. The quartz grains havedeveloped chemical action, mainly are middle-strong chemical corrosion; The surface textures of the quartz grains indicate that the sediments are mainly embouchureenvironment; The result of sand dunes'TL age show that the sand dunes were affected by the change of the sea-level in Holocene epoch and experienced the weathering.