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1.
Natural Hazards - Barriers, which are normally used as highway safety instruments, cause adverse sand deposition damage to pavements along desert highways. To select a suitable barrier type for... 相似文献
2.
沙漠表层粒度与水热变化的环境效应分析──以古尔班通古特沙漠为例 总被引：8，自引：2，他引：6
重点探讨了古尔班通古特沙漠不同类型沙漠区（流动沙漠和固定沙漠区）表层沙粒度组成特征及其与热量传输和含水率的相互关系。实地测量和采样分析结果表明:不同类型沙漠区的粒度结构组成与沙层热量传输、水份迁移和沙面蒸散直接相关,并且对地表的感热和潜热以及沙漠对气候的反馈起到了重要作用。同时,沙漠表层粒度与水热传输变化过程,直接影响沙漠区植物成活率与生长,并对沙漠气候与环境变化产生重要影响。 相似文献
3.
化学固沙材料在干旱沙漠地区的应用 总被引：16，自引：1，他引：16
在查阅大量文献的基础上，探讨了化学固沙原理。通过实地试验，较系统地分析了常用的化学固沙材料、效果及在干旱沙漠地区应用化学固沙材料的适宜性。新型化学固沙材料及其特性的研究是当今化学固沙的重要内容。文章简要介绍了新型化学固沙材料的研究进展。SH为新型高分子材料，具有较高的强度、良好的耐水性、抗冻融和耐老化性能，成本低，喷洒工艺方便、简单，是固沙的理想产品。化学固沙快速方便，但防沙作用差，应开展化学-生物固沙一体化综合研究。固沙植被用新材料及低成本制备技术的研发，将在年降雨量只有数10mm的WN广大沙漠区防沙治沙中具有广阔的应用前景。 相似文献
4.
Mohamed E. Hereher 《Environmental Earth Sciences》2010,59(5):1119-1127
Wind action is the most dominant agent for erosion and deposition in the vast Western Desert of Egypt. Analysis of wind data
from seven meteorological stations distributed along the Western Desert reveals that this desert is characterized by high-energy
wind environments along the northern and southern edges and low-energy wind environments throughout the rest of the desert.
Accordingly, sand drift potential follows the pattern of wind energy. Maximum sand drift potential was observed at the southern
edge (571 vector units, which equals 40 m3/m width/year). Sand drift direction was observed towards the southeast except at the southern part of the desert where the
trend of sand movement was towards southwest. The major dune type recognized on satellite images was the simple linear type.
Linear dunes are generally associated with bimodal wind regime. Rates of sand drift potential and sand dune migration were
greatest at East of Owinate region at the extreme southern part of the desert. Measurements of crescentic sand dune advance
from two satellite images reveal a maximum advance rate of about 9 m/year at the southern part of the desert. Dune movement
creates potential hazard to the infrastructures in this open desert. 相似文献
5.
Lars B. Clemmensen 《International Journal of Earth Sciences》1985,74(3):519-536
Facies studies of well cores from the Bunter Sandstone Formation in the Tønder area, Denmark indicate, that the formation is composed of two desert sand plain sequences associated with sabkha and inland basin (lake?) mudstones. The lower desert sand plain sequence consists of subaerial sand flat deposits overlain by aeolian sand sheet and dune facies topped by interbedded aeolian and ephemeral river deposits. The upper desert sand plain sequence consists of ephemeral river deposits partly interbedded with and overlain by sabkha and inland basin mudstones. Two shoreline sandstones occur in the uppermost part. Both sequences are interpreted mainly in terms of tectonic subsidence of the basin and related upheavals of the source regions. The lower sequence represents a rather continuous progradation of the desert sand plain followed by a rapid transgression of the waters from the inland basin. The upper sequence represents brief periods of fluvial progradation followed by a gradual retreat of the river plain. The most distal part of the sand plain was finally reworked by weak wave-action. 相似文献
6.
沙漠—绿洲过渡带近地表风沙过程研究进展 总被引：1，自引：0，他引：1
受绿洲和沙漠景观格局的双重影响,沙漠—绿洲过渡带是一个对外界条件变化极为敏感的生态环境脆弱带。沙漠—绿洲过渡带近地表风沙过程及其动态演变直接影响绿洲的稳定和有序发展,在空间上制约沙漠的进退或绿洲的变迁。从沙漠—绿洲过渡带局地小气候、沙尘暴、风沙环境、土壤风蚀、风沙输移和绿洲防护体系建设等几个方面比较全面地综述了近数十年来沙漠—绿洲过渡带近地表风沙过程研究进展,并基于当前沙漠—绿洲过渡带生态环境建设与地方需要等面临的实际问题,分析了该领域今后的研究重点和发展趋势。 相似文献
7.
古尔班通古特沙漠工程地质问题--以输水工程为例 总被引：1，自引：0，他引：1
沙漠的工程地质问题随工程类型的不同而不同。本文以输水工程为例,概要地论述了沙漠工程地质问题。风沙危害是沙漠中带有普遍性的问题,频繁而强劲的风力和地表充足的砂粒为风沙危害提供了条件;砂土湿陷性主要与其密度大小有关,当砂的干密度达到1 64g cm3时,湿陷性系数均小于0 015,即可消除湿陷性;渗透变形的形式为流土,破坏临界比降为0 9～1 73,属抗渗能力低的细粒砂土;天然沙漠砂为不冻胀砂,当含水量≤18%时为不冻胀—弱冻胀砂,饱和时为冻胀砂;挖方形成的高边坡在风蚀作用下使坡面增长,裸砂面积加大,加剧对渠道的淤积。 相似文献
8.
FIKRY KHALAF 《Sedimentology》1989,36(2):253-271
Several types of aeolian deposits have been recognized in Kuwait: (a) smooth sand sheets that resemble desert floor sand, (b) immobile sands that include rugged vegetated sand sheets and wadi fill deposits, and (c) mobile sands that form active sand sheets and sand dunes. Simple size frequency curves illustrate the genetic relationship between the various aeolian sediment types. The four size parameters, namely, mean size, sorting, skewness and kurtosis, were calculated. Scatter plot diagrams of sorting versus mean size and sorting versus kurtosis are effective in differentiating smooth sand sheet deposits from dune sands. Active sand sheet deposits can also be recognized because they are usually located between the two end members–smooth sand sheets and dune sands. Size parameters change with location regardless of their types. Coarsening and positive skewness usually increase downwind. Mineralogical and textural characteristics of the aeolian deposits in Kuwait revealed that they are mostly derived from the lower Mesopotamian muddy flood plain deposits, the sand fraction of the Al-Dibdibba gravelly deposits and the disintegrated material from calcretic and gypcretic duricrusts. Distribution of depositional and deflational areas indicates that the northern desert of Kuwait is characterized by a positive sand budget, whereas the southern desert has a negative sand budget. 相似文献
9.
毛乌素沙地沉积物粒度特征与土地沙漠化 总被引：5，自引：0，他引：5
为了研究毛乌素沙地沉积物的粒度特征与土地沙漠化的地质成因类型,通过系统研究沙地及相邻地区晚更新世以来在沙地内部、覆沙黄土区、黄土高原和河流谷地与湖泊等不同地质构造地貌条件下所形成的沉积物粒度特征,指出不同地质成因类型的沉积物是这些地区土地沙漠化的物质基础,区分不同类型的沉积物也是构成不同地质成因类型土地沙漠化分类的理论基础,探讨了不同地质作用对土地沙漠化的贡献及其对土地沙漠化防治方面的意义。研究表明,研究区的土地沙漠化是以各种类型的就地起沙为主要特征,地表径流的水力搬运是沙漠化物质搬运的重要途径。现代毛乌素沙地及其邻区的土地沙漠化是对地质历史时期形成的各种沉积物的进一步搬运、分选和再沉积过程,具有相对复杂的粒度特征。 相似文献
10.
Quaternary desert loess and sandstone-loessite relationships in the geological record raise questions regarding causes and mechanisms of silt formation and accretion. In the northern Sinai-Negev desert carbonate terrain, only sand abrasion in active erg could have produced the large quantities of quartzo-feldspathic silts constituting the late Quaternary northwestern Negev loess. In the continuum of source (medium to fine sand of dunes) to sink (silts in loess) the very fine sand is unaccounted for in the record. This weakens the sand abrasion model of silt formation as a global process. Here, we demonstrate that, as predicted by experiments, abrasion by advancing dunes generated large quantities of very fine sand (60-110 μm) deposited within the dune field and in close proximity downwind. This very fine sand was generated 13-11 ka, possibly synchronous with the Younger Dryas under gusty sand/dust storms in the southeastern Mediterranean and specifically in the northern Sinai-Negev erg. These very fine sands were washed down slope and filled small basins blocked by the advancing dunes; outside these sampling basins it is difficult to identify these sands as a distinct product. We conclude that ergs are mega-grinders of sand into very fine sand and silt under windy Quaternary and ancient aeolian desert environments. 相似文献
11.
再论巴丹吉林沙漠湖泊水的补给来源、补给模式与高大沙山的形成机理 总被引：1，自引：0，他引：1
依据已有研究成果和最新调查资料, 在综述沙漠湖泊与高大沙山研究进展及存在问题的基础上, 深入探讨了巴丹吉林沙漠湖泊水的补给来源、补给模式及高大沙山的形成机理. 结果认为, 沙漠湖泊水和地下水的补给来源不是当地降水和周边雅布赖山-北大山的降水形成的地表洪水, 而是南部青藏高原(包括祁连山)现代大气降水、冰雪融水、高原湖水的远源补给. 补给模式为高原富含CO2气体和CaCO3的入渗水, 通过深大导水断裂通道形成的区域地下水流循环系统, 源源不断地自南向北运移到沙漠地带, 地下水在通过沙漠湖泊区弧形"叠瓦状"垂向导水构造断裂向上越流过程中被广泛分布的岩浆岩加热, 沿断层溢出地表形成湖泊群, 同时导致水中CO2的释放和CaCO3的沉积, 形成钙华体. 高大沙山的形成机理是深层地下热水向上越流补给了沙漠覆盖区, 在承压水头以下形成鼓丘状的沙漠地下水, 承压水头以上, 水蒸汽继续向上运移并被凝结在沙粒表面, 未被吸附凝结的热水蒸汽继续向上运移并被吸附在新沉积的沙粒表面, 形成湿砂层并接受更新的沙粒沉积, 如此反复循环, 则沙丘高度不断增加, 逐步形成高大的固定沙山. 相似文献
12.
沙尘暴形成史初步研究——中国沙漠几个典型地质学记录的实证 总被引：1，自引：0，他引：1
以位于沙漠黄土边界带的榆林、阿羌和米浪沟湾地层剖面为典型例证 ,讨论了 110 0kaBP以来中国沙漠沙尘暴的形成、发展和演化过程。提出在过去的 110 0ka中该区总共记录了 4 2个沙尘暴时期 ,并与 4 1个间沙尘暴时期构成比较连续且交替进行的一系列沉积演化历史。其中 ,最强烈的沙暴期发生时间大致在 6 2 0kaBP和 6 80kaBP前后 ,最温暖的间沙尘暴期出现在 5 90～ 5 0 0kaBP和15 0～ 70kaBP。研究认为 ,110 0kaBP以来因沙尘暴期与间沙尘暴期交替出现而形成的沉积旋回 ,是自那时以来在冰期、间冰期气候波动影响下冬夏古代季风相互对峙、交替演化形成气候旋回的结果 相似文献
13.
对沙漠内部典型河流沿线沙丘石英颗粒表面微形态特征的系统研究尚少。沿塔里木盆地南缘克里雅河下游丹丹乌里克、喀拉墩、圆沙古城、北方墓地及其北部塔里木河一带的沙丘顶部采到5件表沙样品。扫描电镜观察172颗经能谱挑选的石英颗粒表面微形态,筛析法测定5件样品的粒度。结果表明:1）丹丹乌里克样品以极细沙为主,其余均以细沙为主,各样品几乎不含黏土;2）样品磨圆度特征以次棱和次圆状为主,圆状很少,未见棱状特征,次棱状与次圆状特征之间消长关系显著,沙漠南北边缘样品的次棱状特征出现频率较腹地高;3）颗粒中V形坑频率呈现出沙漠边缘较高腹地低的特征,而沙漠边缘的化学作用结构特征低于腹地。石英砂表面特征结构以机械作用为主,同时伴生化学环境作用特征,可认为克里雅河下游沙物质包括了河流、冰川与戈壁成因及风输送而来的颗粒;颗粒表面特征总体新鲜,沙丘应较年轻。纵穿塔克拉玛干沙漠沉积物样品的表面微形态观察与粒度测定,为该地区沉积环境分析与沙丘砂溯源研究增添了新数据。 相似文献
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15.
D. W. HUMPHRIES 《Sedimentology》1966,6(2):135-152
The occurrence of the rare phenomena of a booming sand is recorded and an account given of its behaviour in the field. Its sedimentological properties are compared with those of a squeaking sand from the seashore. Both sands are moderately to wellsorted, and show similar roundness and sphericity. The desert sand is silent, whereas the seashore sand can be made to emit a noise in the laboratory. The marked distinction between the sands lies in the mechanical analyses based on the number frequency of grains, rather than on the weight frequency. A “body-centred cubic” packing has been proposed for the desert sand and a “rhombic” packing for the seashore. Shear-box tests on the disturbed sands appear to support the hypothesis of two different modes of packing. The source of the characteristic booming sound is discussed, but it is suggested that an explanation is more likely to be forthcoming from field investigation than from small-scale laboratory studies. 相似文献
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17.
沙漠砂抗剪强度特征及其与静力触探指标间的关系 总被引：2，自引：0，他引：2
通过室内系列化的直剪试验和静力触探模拟试验,对沙漠砂的抗剪强度特征取得了规律性的认识,并建立了砂土内摩擦角与锥尖阻力之间的经验关系,为今后在沙漠地基勘察评价中用静力触探方法估计砂土内摩擦角创造了条件。 相似文献
18.
The microped size distribution of erodible soils is one of the main factors controlling the emissions of mineral aerosol. To date, the microped size distributions of desert soils in natural field conditions are not well known and thus the existing dust source models cannot be applied to natural sites. Based on dry sieving and elemental analysis of 26 soil samples collected in arid and semiarid regions, it is shown that the microped size distributions of these desert soil samples involve a combination of four major mass size populations. These four size populations correspond to salty soils, fine quartz sand, coarse dune sand and aluminosilicate silt. We show that the microped size distributions of the various desert soils, according to their mineralogical characteristics, can be calculated by a mixture involving two or three of these four populations. The main field of application for this scheme is the characterization of the erodible soil size distributions for modelling the atmospheric dust cycle. 相似文献
19.
Based on the development of railways in desert areas of China, the types, characteristics, schemes, measures and technical systems of wind-sand disaster prevention and control were systematically analyzed in this paper. In view of the regional characteristics of sandy areas and the genres of railway sand damage in China, the results achieved and problems faced of wind-sand hazard and prevention technology in quicksand surface, plateau cold region and Gobi gale area were discussed as a case study. Combined with the expanding trend of railways in desert zone in China at present, starting from the theoretical research and the practice of sand control in engineering, it was proposed that the railway sand harm of complicated terrain and special environment is the key research direction in the field of wind-sand engineering in the future, which is also the crucial and difficult point in the protection and control of railway sand hazard in sandy zones. 相似文献