摘要
以新疆艾比湖周边的柽柳沙堆为研究对象,对柽柳沙堆表层及丘间地砂物质进行系统采样和粒度分析。结果表明:柽柳沙堆表层沉积以极细砂为主(占34.60%),其次是细砂(占21.90%),极粗砂含量最少(占0.08%);丘间地沉积物粒度组成与沙堆相似,只是各组分含量不同。柽柳沙堆表层砂物质平均粒径为4.08Φ;分选性很好;偏度属于极负偏;平均峰度属于尖窄峰态。柽柳沙堆砂的平均粒径与分选性(r=-0.869)、平均粒径与峰度(r=-0.830)都呈现高度负相关;分选与峰度呈现高度正相关(r=0.889);分选与偏度呈现不显著正相关;平均粒径与偏度、偏度与峰度都无相关性。区域风动力条件是影响柽柳沙堆粒度组成及其空间变异的主要因素之一。
Ebinur Lake in Xinjiang has become one of the largest sources of dust storms. Nabkhas commonly distributing in arid and semi-arid areas, are mounds composed of wind-borne sediment that trapped by shrubs. The Tamarix nabkha which widely distributes in Ebinur Lake is mainly distributed on bayou and alluvial fan fringe of north-south piedmont. In this paper, the measured results of sediment grain size samples collected from the surface of Tamarix nabkhas in Ebinur Lake are tested and analyzed. The results show that very fine sands are dominant in Tamarix nabkha surface sediments, it account for 34.60%, followed by the fine sand, accounting for 21.90%, then coarse silt, accounting for 13.21%. The very coarse sand content is the least, that accounts for 0.08%. The surface sand material＇s mean diameter is 4.08 qb, due to the top of shrub being destroyed by human, the slope top particle mean diameter is the most coarse. The mean sorted index is 0.12Ф which belongs to well-sorted and the slope top sort is the poorest, because on slope top wind-sand flow was disturbed by the plant and sand chaotic melange. The coefficient of skewness is - 0.43Ф which is very negative skewness. This mean surface sediment of Tamarix nabkha is main fine components; the mean kurtosis value is 1.49Ф which belongs to leptokurtic distribution, consequently wind action process is persistent and sort is well and it shows leptokurtic distribution. The wind- sand flow moves to slope top, due to gravity action and interception by plant, the crude grain material is first depos- ited, so that the erosion action on windward slope more intensive than sedimentation action, leading to grain being coarse. Because shrub of nabkha top was destroyed by human in the study area, therefore the sand material mean diameter is coarse ; eddy zone of leeward slope being uplift and extending downwind direction, sand grain was largely deposited on leeward slope and reached a certain extent which can lead to sand falling phenomenon. Through analyzing the grain size
出处
《干旱区地理》
CSCD
北大核心
2010年第4期525-531,共7页
Arid Land Geography
基金
国家自然科学基金项目(40761004)
中国沙漠气象科学研究基金项目(Sqj2007005)资助
关键词
柽柳沙堆
粒度参数
艾比湖
Ebinur Lake
Tamarix nabkha
grain size parameter
