对新疆伊犁河谷塔克尔莫乎尔沙漠抛物线形沙丘表层78个风成沙样的粒度分析表明,平均粒径均值为220 μm,平均中值粒径为299 μm,标准偏差平均为1.98,偏度平均为-0.29。纵向分布上,从风蚀洼地到迎风坡下部,风成砂的平均粒径和分选性波动变化明显,沿迎风坡向上平均粒径减小,在脊线附近有较粗粒径的分布带。在沙丘背风坡平均粒径减小、负偏增加、分选性较差。在粒度参数等值线及三维分布方面,风蚀洼地和迎风坡下部呈现沿沙丘轴向交替分布的封闭等值曲线,两侧沙臂粒度参数大小波动变化,沙臂北翼坡脚粒度组成呈现很高的负偏和峰度值,反映在区域风况作用下,抛物线形沙丘本身地形起伏、两侧沙臂灌丛沙堆分布对沙丘表面风沙流运移有影响,风沙流与沙臂斜交在背风坡产生涡流引发较强的沉积作用。
The grain size record of 78 aeolian sand samples collected from the Takermohuer Desert in the Yili River Valley, Xinjiang shows that the average value of mean grain size (Mz) is 220 μm, the average value of median size (Md) is 299 μm, the average standard deviation is 1.98 and the average skewness is -0.29. The longitudinal distribution of the grain size displays an obvious variation in Mz and sorting features from wind-erosion depression to the bottom of the dune windward slope. The Mz decreases along the windward slope and forms a coarse particle zone in the ridge of dune. While in leeward slope of the dune, the grain size record shows a decreased Mz, a negative skewness and a poor sorting. The 3D contour lines of the grain size parameters present alternating distribution of closed contour curve along the wind-erosion depression and the bottom of windward slope. On both sides of the sand arm, the size parameter is fluctuated; and the grain composition presents negative skewness and cuspate kurtosis on north wing slope of sand arm. As mentioned above, the wind activities, topographic environment of parabolic dune and the scrubs on both sand dune arms exert great influence on the sand flow migration on surface of sand dunes. And the eddy currents in the leeward caused by the skew of the sand flow and sand arms trigger strong sedimentation in the leeward slope.
[1] Pye K,Tsoar H.Aeolian Sand and Sand Dunes[M].London,UK:Unwin Hyman,1990:186-187.
[2] Cooke R U,Warren A,Goudie A S.Desert Geomorphology[M].London,UK:UCL Press,1993:235-240.
[3] Finnigan J J,Neil D,Lees B G,et al.Modelling the wind flow pattern around a parabolic sand dune[J].Mathematics and Computers in Simulation,1990,32:89-94.
[4] Robertson-Rintoul M J.A quantitative analysis of the near-surface wind flow pattern over coastal parabolic dunes[M]//Nordstrom K F,Psuty N P,Carter R W G.Coastal Dunes:Form and Process. London,UK:Wiley,1990:57-78.
[5] Craig M S.Aeolian sand transport at the Lanphere Dunes,Northern California[J].Earth Surface Processes and Landforms,2000,25:239-253.
[6] Arens S M,Slings Q,DeVries C N.Mobility of a remobilised parabolic dune in Kennemerland,The Netherlands[J].Geomorphology,2004,59:175-188.
[7] Anderson J L,Walker I J.Airflow and sand transport variations within a backshore-parabolic dune plain complex:NE Graham Island,British Columbia,Canada[J].Geomorphology,2006,77:17-34.
[8] Hugenholtz C H,Wolfe S A,Walker I J,et al.Spatial and temporal patterns of aeolian sediment transport on an inland parabolic dune,Bigstick Sand Hills,Saskatchewan,Canada[J].Geomorphology,2009,105:158-170.
[9] Hansen E,DeVries-Zimmerman S,Van Dijk D,et al.Patterns of wind flow and aeolian deposition on a parabolic dune on the southeastern shore of Lake Michigan[J].Geomorphology,2009,105:147-157.
[10] 陈秀玲,李志忠,陈蜀江,等.基于差分GPS测量数据的抛物线沙丘形态特征研究[J].福建师范大学学报(自然科学版),2010,26(3):84-89.
[11] 杜会石,哈斯,吴霞,等.3S技术在抛物线沙丘形态特征研究中的应用[J].地理与地理信息科学,2011,27(5):33-36.
[12] 闫娜,哈斯,刘怀泉,等.抛物线形沙丘的形态与演变研究进展[J].中国沙漠,2010,30(4):801-807.
[13] 张萍,哈斯,杜会石,等.抛物线形沙丘与油蒿灌丛之间的动态关系[J].科学通报,2011,56(35):3003-3010.
[14] 吴霞,哈斯,杜会石,等.库布齐沙漠南缘抛物线形沙丘表面粒度特征[J].沉积学报,2012,30(5):937-944.
[15] 杜鹤强,韩致文,王涛,等.新月形沙丘表面风速廓线与风沙流结构变异研究[J].中国沙漠,2012,32(1):9-16.
[16] 钱广强,董治宝,罗万银,等.巴丹吉林沙漠地表沉积物粒度特征及区域差异[J].中国沙漠,2011,31(6):1357-1364.
[17] 哈斯,王贵勇.沙坡头地区新月形沙丘粒度特征[J].中国沙漠,2001,21(3):271-275.
[18] 张正偲,董治宝,钱广强,等.腾格里沙漠西部和西南部风能环境与风沙地貌[J].中国沙漠,2012,32(6):1528-1533.
[19] 钱广强,董治宝,罗万银,等.回涡沙丘的形态特征与表面物质组成[J].中国沙漠,2012,32(3):587-592.
[20] 李志忠,武胜利,陈蜀江,等.伊犁塔克尔莫乎尔沙漠风沙地貌初步研究[J].新疆农业科学,2008,45(S3):113-118.
[21] 成都地质学院陕北队.沉积岩(物)粒度分析及其应用[M].北京:地质出版社,1978:31-65.
[22] Bagnold R A.The Physics of Blown Sand and Desert Dunes[M].London,UK:Methuen,1941.