【作者】 宋艳；

【导师】 赵元杰；

【作者基本信息】 河北师范大学 ， 自然地理学， 2008， 硕士

【摘要】 罗布泊及其临近地区位于塔里木盆地东部,北有库鲁克塔格山、东北有克孜勒塔格山和依格孜塔格山,东与甘肃临界白山毗邻,南为阿尔金山,西邻塔克拉玛干沙漠和库姆塔格沙漠,东部阿奇克谷地与疏勒河和河西走廊相连。罗布泊是塔里木盆地各大河流的归宿地,它的环境演变是整个塔里木盆地和周边山地环境演变的缩影。本区冬季气候干燥寒冷,夏季高温少雨,发育着一种适合干旱区的生物地貌类型——红柳沙包。研究发现,红柳沙包具有清晰的“年层”构造,他和树木年轮一样,具有很强的计年和储存环境信息的功能,可以用来探讨和恢复数百年来的气候和环境变化。从实地勘测和卫星图片判断,罗布泊地区的红柳沙包主要分布在塔里木河、孔雀河、米兰河等三角洲地带。本文以罗布泊地区红柳沙包为主要研究对象,运用风沙地貌学的方法,在野外考察和观测的基础上,结合沉积物的粒度实验等测试分析手段,初步获得了罗布泊地区粒度变化特征及其成因机制。基本结论如下:(1)所有罗布泊地区红柳沙包沉积纹层沙物质的机械组成均以细沙粒为主,粉砂、粘土次之,极少含粗砂。三个红柳沙包沙物质的平均粒径分别为3.20Ф、2.76Ф、3.40Ф。沙包沙层的粒级组成、粒度特征参数、粒级分布曲线以及粒度累计概率曲线等对环境指示意义都较为明确。(2)通过对罗布泊地区不同地段红柳沙包粒度数据的对比分析,可以研究不同时期风力强度和物源的变化,从而获得近百年来发生在罗布泊地区的环境变化信息。(3)通过对红柳沙包、沙漠沙丘、海岸带沙丘粒度的对比分析,可以反应出红柳沙包在表征风沙地貌过程、区域环境演变、土地覆盖变化等方面具有的独特作用,从而为相关地区环境变化研究提供新的理论依据和技术参考。(4)沙层厚度与下垫面沙源丰富度有关。红柳沙包周围沙源越丰富,每年累积的沙层厚度越高,结合相关气象资料表明,罗布泊地区百余年来的气候由较干旱向较湿润方向发展。(5)红柳沙包不同部位的沙物质粒径大小呈有规律地变化,即迎风坡坡脚和坡中的粒度粗于背风坡坡脚和坡中,坡顶沉积物粒径最小;红柳沙包不同部位的粒度组成,同样与其周围的风况条件、物质来源有很大关系。红柳沙包顶部植物能增加沙堆表面的粗糙度,对气流阻滞消能,从而使红柳沙包在不同部位呈现出相应的粒度特征。更多还原

【Abstract】 Lop Nur Region and its adjacent areas are located on the eastern Tarim Basin. Its north is the Kuruktag Mountain, northeast is the Keziletag Mountain and the Yigtag Mountain, east is the Baishan and Gansu Province, south is the Aljin Mountain, and west is the Taklimakan Desert and the Kumtag Desert. Eastern Aqik Valley is linked with Shule River and Hexi Corridor. The topography is like an inverted bottle. Lop Nur is the destination of every river in Tarim Basin. Its environmental evolution is the epitome reflecting on the Tarim Basin and surrounding mountains .Winter climate in this region is dry and frigid, summer has little rain and high temperature. Tamarix Cone is a kind of biological landform. Some of them have the clear "annual stratum" structure and the function of dating and storing environmental information as tree rings. From the analysis on the spot and reconnaissance report, Tamarix Cone in the Lop Nur Lake region of southern Xinjiang are mainly distributed in the deltas of Tarim River, Kongque River, Milan River. etc.The Subject investigated of this paper is with Tamarix Cone in Lop Nur region, utilize geomorphology method, on the basis of inspecting and observing in open country, testing the analytical means combining with the deposit size experiment etc to research the characteristic of grain size and the cause of Vegetation Dunes in Lop Nur Drainage Area. The basic conclusions are as follow:①All of sandy materials of sedimentary veins in studied section mainly consist of the fine sand, clay is little. Sand materials average particle size is followed by 3.20Ф, 2.76Ф, 3.40 in which of three Tamarix Cones. Besides of the sedimentary thickness of sandy materials, the grain-size composition,parameter of grain-size characteristics, and very little gravel sand content, grain-size distributed curve as well as accumulated probability curve have more clear environmental indication.②By the comparative analysis of Tamarix Cone grain-size data in the different locations of Lop Nur Region, we do research into the change of wind strength and provenance during different periods to obtain the information of environmental change during the last one hundred years.③By means of comparative analysis of grain-size of the Tamarix Cone, desert sand dunes and coastal zone sand dunes, they also response the unique function in the area of geomorphologic processes of wind-drifting sand, environmental evolution and land-cover change in order that they can provide new theoretical basis and technical reference for the research of environmental change in relevant areas.④The sand bed thickness is related to the surface sand richness. For Tamarix Cone, the richer sand source around, the higher sand bed thickness every year. According to the relevant meteorological data, the climate in Lop Nur region has been changing from more drying to more humid over the past one hundred years.⑤The sand particle size of Tamarix Cones was a regular pattern change on different parts, the sand particle size of windward base of slope and middle slope is rough on the leeward side, sediment particle size of slope’s tip is minimum. It can be believed the sand particle size of Tamarix Cone on different parts that have relation to the winds and the source of material, meanwhile the plant in dunes will increase the surface roughness of the sand to block airflow dissipation. So changes in the structure of air flow in Tamarix Cone is showing the corresponding particle size characteristics on different parts.更多还原