巴丹吉林-腾格里沙漠间沉积物粒度和磨圆度的空间分异

Spatial Differentiation of Grain Size and Roundness of Sediments in the Badain Jaran-Tengger Desert

为探索巴丹吉林沙漠与腾格里沙漠交界处风沙口的沉积物分异特征,沿风沙口主风向走向(NW-SE)对沙丘表层沉积物取样,并进行粒度和磨圆度分析。结果表明,(1)沙丘表层沉积物中砂含量占比最高,细沙和粗砂含量次之;迎风坡顶部中砂占比最多,迎风坡中部细砂占比最多,背风坡底粗砂占比最多。(2)沿主风向从风沙口至腾格里沙漠腹地的平均粒径和中值粒径呈波动增大趋势;分选系数呈波动降低的趋势;偏度值在正负偏度值之间波动。(3)沉积物石英砂的磨圆度次圆占比最高;迎风坡顶部沙样的磨圆度最好,背风坡底的磨圆度最差。

In order to explore the differentiation of the characteristics of sediments along the direction of the wind-sand mouth at the junction of the Badain Jaran Desert and the Tengger Desert,the grain size and rounding of the surface sediments from the wind-sand mouth to the hinterland of the Tengger Desert along the main wind direction of the wind-sand mouth Degree for analysis.The results show that,(1)the composition of the overall soil composition is mainly sand grains,of which medium sand accounts for the highest proportion,followed by fine sand and coarse sand;from the perspective of different sampling locations,the top of the windward slope has the highest medium sand content The fine sand content is the highest in the middle of the windward slope,and the coarse sand content is the highest at the bottom of the leeward slope,which is the result of wind sorting.(2)Along the main wind direction,the average particle size and median particle size from the sand mouth to the hinterland of the Tengger Desert fluctuate and increase;the sorting coefficient fluctuates and decrease;the skewness value is between the negative skewness and the positive skewness.(3)Generally speaking,the roundness of the sediment quartz sand is moderate,mainly sub-circular,and there are not many round particles.The sand at the top of the windward slope has the best roundness,and the bottom of the leeward slope has the worst roundness.