线形沙丘的风沙沉积特征与内部构造   总被引：4，自引：4，他引：4  

钱征宇  刘守勤 《中国沙漠》1994,14(3):25-30

本文介绍了线形沙丘不同部位风沙沉积物的粒度特征、易溶盐含量特征和颗粒形态特征，通过现场全断面开挖线形沙丘剖面，对线形沙丘的内部构造进行了观测，结合研究地区的风信资料，对线形沙丘的风沙堆积过程进行了初步分析研究。  相似文献   

晚更新世末期南海北部陆架的古地理探讨   总被引：7，自引：3，他引：7  

吴正  冯文科 《地理学报》1993,48(6):491-496

根据地球物理综合调查,沉积物的粒度、矿物成分、石英砂粒扫描电镜分析,14T测年,以及微体古生物等成果,表明南海北部外陆架地区在更新世末期,冬半年气候干寒,东北风强劲,风沙活动强烈,砂丘广布,为干寒多风沙的自然环境。  相似文献   

Movement of a small slipfaceless dome dune in the Namib Sand Sea, Namibia     

C. S. Bristow  N. Lancaster   《Geomorphology》2004,59(1-4):189

The migration of a small slipfaceless dome dune close to the northern edge of the Namib Sand Sea has been measured by topographic survey. The dune dimensions are 45-m wide and 1-m high with a volume of 551 m³ that has been calculated as the difference between the dune's surface elevation and an interdune surface extrapolated from measurements around the edge of the dune. The migration direction, 64°, and distance moved, 90 m, are measured against stakes set out in 1976. The dune has moved about 90 m between 1976 and 1999. This is an average linear migration rate of around 4 m year⁻¹, and is equivalent to an annual sand transport rate of about 1.2 tonnes m⁻¹ year⁻¹. The calculated total potential sand flow in this part of the Namib Desert is 119 tonnes m⁻¹ year⁻¹, and the resultant potential sand flow is 63 tonnes m⁻¹ year⁻¹. The dune migration is therefore about 1% of the total potential sandflow and 2% of the resultant indicating that dune migration is only a small part of total potential sand transport. The results suggest that small slipfaceless dome dunes are very inefficient at trapping sand, and that winds blowing across the interdune in this area are undersaturated with sand.  相似文献   

塔克拉玛干沙漠东南部气象参数及沙丘横断面风速特征研究     

陈顺三  马淑红薛洁罗静  吴新国程华 《沙漠与绿洲气象(新疆气象)》2005,28(3):22-23,26

以塔克拉玛干沙漠东南部国道G315线若羌-且末沙漠公路沿线为研究区域，分析研究了塔克拉玛干东南部近43a气候特征和气候变化趋势。在上述基础上，选取复合沙丘顶部、半坡、底部和平沙地四种典型风沙地貌为床面，采用YNZX—多功能全自动集沙仪，进行野外风沙监测，获取一批有关沙丘横断面不同高度脉动风速、输沙量的珍贵资料，分析了塔克拉玛干沙漠东南部沙丘横断面风速特征，为沙漠地区修筑公路以及选线参数研究提供科学依据。  相似文献   

A Multi-cycle Climatic Fluctuation Record of the Last Interglacial Period:Typical Stratigraphic Section in the Salawusu River Valley on the Ordos Plateau,China   总被引：5，自引：0，他引：5  

LIBaosheng DavidDianZHANG WENXiaohao DONGYuxiang ZHUYizhi JINHeling 《《地质学报》英文版》2005,79(3):398-404

The Last Interglacial Period strata in the Milanggouwan section in the Salawusu River valley on the Ordos Plateau, China, have 8.5 sedimentary cycles composed alternately of eolian dune sands, fluvio-lacustrine facies and paleosols. Based on comprehensive analyses on the distribution of magnetic susceptibility and CaCO3 and paleo-ecology indicated by fossils in the region, it is considered that the sedimentation cycles resulted from dry-cold and warm-humid climate fluctuations. Magnetic susceptibility values and CaCO3 contents in stratigraphic sectors Ⅰ, Ⅲ, Ⅴ and Ⅱ, Ⅳ basically respectively present peaks and low vales, and the former three can in time correlate with MIS5a, MIS5c and MIS5e successively and the latter two with MIS5b and MIS5d. In addition, some horizons of eolian dune sands and the low vales of their magnetic susceptibility and CaCO3 are also correlated with 6 periods of cooling events indicated by the higher content of foraminifer Neogloboquadrina pachyderma (S.) documented in the V29-191 drill in the North Atlantic and the cold events recorded by δ^18O in the ice cores in GRIP, especially with 9 periods of dust events in Chinese Loess Plateau.  相似文献   

Development of a cliff-top dune indicated by particle size and geochemical characteristics: Rubjerg Knude, Denmark     

SAMANTHA E. SAYE  KENNETH PYE  LARS B. CLEMMENSEN† 《Sedimentology》2006,53(1):1-21

Particle size and geochemical data have been used to investigate the development of a large cliff-top dune at Rubjerg Knude, located on the western coast of Jutland, Denmark. Textural parameters and geochemical ratios provided useful indicators of the dune sediment provenance and mode of evolution of the dune. The dune sediments themselves showed no significant spatial particle size trends and reflect a number of processes, including grainfall, wind-ripple migration and avalanching (grainflow), which formed a high proportion of the deposits on both the stoss and lee sides of the present dune. Fine grainfall sediments, which have accumulated to form a sandplain in the lee of the dune, show fining and improved sorting with distance, and extend more than 2 km downwind of the dune crest. Comparison of the textural and geochemical data from Rubjerg Knude and other locations on the Jutland coast indicates that, although there is a contribution of sand to the dune from local marine sources, the main source of sand to the cliff-top dune and sand plain sediments has been provided by the wind erosion of the underlying cliffs, which are composed of Weichselian age sandy glaciofluvial and glaciolacustrine deposits. Optically stimulated luminescence dating indicated an apparent age for the sand at the base of 274 ± 14 years. If this date is reliable, it suggests that accumulation of the aeolian sand in this area began within approximately the last 300 years. Map and photographic evidence indicate that the modern high dune only began to form after 1885, apparently associated with an acceleration in the rate of coastal cliff retreat.  相似文献   

Simulating study on barchan dune     

凌裕泉  吴正  刘绍中  李长治 《中国地理科学(英文版)》1998,8(2):168-175

ＳＩＭＵＬＡＴＩＮＧＳＴＵＤＹＯＮＢＡＲＣＨＡＮＤＵＮＥ①ＬｉｎｇＹｕｑｕａｎ（凌裕泉）１ＷｕＺｈｅｎｇ（吴正）２ＬｉｕＳｈａｏｚｈｏｎｇ（刘绍中）３ＬｉＣｈａｎｇｚｈｉ（李长治）１１ＩｎｓｔｉｔｕｔｅｏｆＤｅｓｅｒｔＲｅｓｅａｒｃｈ,ｔｈｅＣｈｉｎ...  相似文献   

珠江三角洲新石器考古文化与古地理环境   总被引：12，自引：0，他引：12  

黄光庆 《地理学报》1996,51(6):508-517

珠江三角洲新石器时期的贝丘和沙丘类文化属沿海渔业文化带，其产生和发展与全新的世海面及海陆变迁密切相关。贝丘和沙丘类古文化是随６０００ａＢＰ以前的海侵而产生的；其文化的发展和盛衰过程，在时间和空间上与珠江三角洲海陆环境演变序列都十分吻合。  相似文献   

据高灵敏度航空伽玛能谱资料探讨内蒙巴彦浩特盆地（腾格里沙漠）第四系成钾远景     

崔天秀 《盐湖研究》1996,(Z1)

巴彦浩特盆地自中生代至今一直是一自流水的构造盆地，其具有成钾的构造、气候、水文以及古盐释放等有利条件。该区存在着高灵敏度航空伽玛能谱测量发现的现代高钾异常区，由区内已知盐类矿床（点）的存在及铀、钍元素的地球化学的分布特点知，高钾异常与含钾的盐类物质密切相关。高钾异常的分布及其形态特征表明了本区可能存在较深层卤水，并高钾异常的形成是由于沙丘带与盐湖带问的风积作用、两者间的内循环作用以及两者对较深层卤水存在的蒸发作用的共同结果。根据统计及估算，本区可称之为一具一定远景储量的钾盐远景区。它反映了钾盐富集的一种不同形式，实则体现了构造、气候、水文、盐湖、沙漠五者的密切相关和极好的统一，是沙丘（山）型钾盐成矿模式的代表。  相似文献   

海南岛东北部海岸沙丘的沉积构造特征及其发育模式   总被引：19，自引：1，他引：19  

吴正  吴克刚 《地理学报》1987,(2)

海岸沙丘沉积构造中既有大型交错层理,也具某些区别于内陆沙丘构造的特征,如厚层顶积层的保存及变形层理的普遍存在。 本区海岸沙丘形成于东北季风,沙源来自海滩砂。从海滩后滨向陆地的沙丘类型依次是海岸前丘、横向沙丘和新月形沙丘、抛物线沙丘、纵向沙丘、海岸沙席。其中海岸前丘和沙席为海岸沙丘区别于内陆沙丘的特有类型。本区海岸沙丘的发育开始于3000年前。  相似文献