Study On The Grain Size Of Surface Sediments Of Parabolic Dune In Ebinur Lake Basin, Xinjiang

Parabolic dunes are mainly distributed in the water, vegetation conditions bettersemi-arid and sub-humid sandy grassland environment, as well as sandy coast,lakeshore and arid desert edges.Based on the parabolic dune field sampling EbinurLake distribution characteristics of5cm sediment samples, combined with vegetationplots, wind power and other conditions for obtaining a preliminary surface sedimentgrain size characteristics parabolic dunes.（1）Parabolic dunes on the surface Ebinur Lake Basin220sediment samplesparticle size analysis showed that: particle size distribution between0.399μm~2116.54μm there> particles, mainly in the fine sand (26.902%), medium sand(22.346%), coarse sand (18.434%), very fine sand (11.628%), very coarse sand(11.541%) five main grain size, grains of sand-based group. The average particlesize distribution of the sediment-0.223-7.244Ф (6.595-1166.757μm), the meanaverage particle diameter is1.853Ф (μm), belong to the scope of the sand. Sortingcoefficient average is1.372Ф, sorting poor. Skewness values ranging from verypositive to negative bias bias exists, the average is0.192Ф, positively skewed.Kurtosis values are from platykurtic to leptokurtic, with an average of1.147,it’sleptokurtic.（2）Different parts of the surface topography analysis showed that the particlesize characteristics of parabolic dunes: grain size composition of the differenttopography positions sediment samples are still concentrated in very fine sand, finesand, medium sand, coarse sand, very coarse sand on the pole five grain sizesegments, Composed of various parts of the sediments of sand-based.Thickness ofthe particle size fraction particle size distribution of the content in accordance with1Ф (500μm) the limit of the standard divided as follows: the highest northern wingcorner coarse ingredients and place between the two wings is the highest fineingredients. In the wings wing coarse component (35.62%,43.59%) wassignificantly greater than the particle size of sediment wing angle (29.67%,28.15%);coarse ground ingredients gradually increased from the wings to the top of the hillbetween the content, but from the top of the hill to leeward its base showed a gradualdecrease fine ingredients on the contrary, that the high windward leeward slope thancoarse content.（3）Parabolic dune surface characteristics in different parts of the particle sizeparameters: average particle size of north wing of1.380Ф (422.123μm) the thickest, most thin wings to the mound between average particle size of2.435Ф (223.423μm),from the wings to the mound between the ground top of the average particle size isincreasing, from top to toe leeward slope sediments gradually become smaller;various parts of the parabolic dune surface sediments belong sorting is poor, theworst between the two wings of hill land (1.667Ф), leeward slope slope in sorting thebest (1.193Ф), windward leeward slope than sorting slightly better; sedimentfrequency curve skewed distribution at0.122~0.242Ф all belongs to positive bias;parabolic dune surface distribution of kurtosis values between0.993~1.373Ф,including mesokurtic to leptokurtic，leeward of skewness is smaller than thewindward slope.（4）The average particle size, sorting coefficient, skewness and kurtosisparameters of six binary relation4scatterplot shows the correlation: the averageparticle size and sorting coefficient, the average particle size and kurtosis, sortingcoefficient and peak state showed a significant positive correlation, the remainingcorrelation is not high.（5）Parabolic dune surface sediment grain size frequency curve mainly unimodal（46%）, also have bimodal (26%) and triplet (28%), which indicates the source ofthe dune sediments in the study area into two or more, mostly lacustrine sediments,eolian sediments; granularity cumulative probability curve showed typical creep,saltation and suspension characteristics of three section type, parabolic dunemovement pattern in the surface sediments dominated saltation.（6）Through the vegetation and wind conditions data analysis from the study areashows that: The Ebinur Lake Basin parabolic dune sediments grain size distributionby the combined effect of vegetation quantity, coverage, the growth status and thewind.