【摘要】 经对图们江河口沼泽沉积物的粒度分析,其粒度特征:①分选差,粒径φ值为5.66~8.74(0.020 mm~0.002 mm),平均φ值为7.57(0.005 mm);②粒级构成为:粉砂74.21%,黏土25.79%;③频率曲线以双峰态为主,主要为负偏态。热释光测年结果表明该套样品沉积时间为晚更新世末期至今。根据沉积物粒度分布特征推断该区沼泽沉积物主要为图们江碎屑物由上游搬运到河口地区,堆积在河床和河漫滩上,在旱季由风搬运到沼泽中并堆积下来。雨季的面流也将少量细粒碎屑搬运到沼泽中并沉积下来。更多还原

【Abstract】 By analyzing the grain-size characteristics of swamp deposits near the debouchment of Tumen River,it is found that the grain-size characteristics are as follows:(1)the grading of the samples is poor and of the grains diameters(φ)ranges between 5.66 and 8.74(0.020 mm～0.002 mm) and a mean of φ is 7.57(0.005 mm);(2) the grades are composed of silt(74.21%) and clay(25.79%);(3)the major frequency curves show double peaks and negative in skew.The results of TL dating show that the sediments were formed from the end of late Pleistocene to now.Based on the grain-size distributions,it is inferred that the fragments deposited in the swamps are first transported from upper reaches to the debouch ment area of the Tumen River,and accumulated on the riverbed and the floodplain,then transported again in dry season by wind and piled in the swamps.In rainy season the flows on genlte slopes surounding the swamps also carry some fine-grain fragments to the swamps and leave them there.更多还原