【作者】 陆莹；

【导师】 高宏； 王乃昂；

【作者基本信息】 兰州大学 ， 环境科学， 2012， 硕士

【摘要】 巴丹吉林沙漠以沙山、湖泊、鸣沙、泉水、寺庙五大自然、人文景观吸引着国内外学术界的长期关注和研究,尤其是对沙漠湖群的形成机理至今未形成统一的见解。研究巴丹吉林沙漠湖泊水化学是了解沙漠湖泊水质的一项基础性工作,探明其时空格局、变化特征,可为后续探究沙漠湖群形成机理这一科学问题提供参考。本文是在2009、2010、2011、2012年连续四年对巴丹吉林沙漠开展野外科学考察、取得大量第一手湖泊水文数据资料的基础上,借用水文地球化学的相关手段与方法,较全面地分析了巴丹吉林沙漠湖泊水化学的时空分布特征,并尝试对其形成原因做了一定的解释。首先,通过对比2009年9月与1999年9月、2010年9月,以及2010年9月和2011年1月、4月、7月的沙漠湖泊水化学分析结果,初步探明了巴丹吉林沙漠湖泊水化学的年际、年内变化特征；其次,针对2010年9月采集的119个湖泊的水样,较全面地分析了其水化学的空间分布特征；第三,选择沙漠典型湖泊——诺尔图,分别于2011年4月、7月、10月和2012年1月对其展开分层采样工作,以观测其季节性的分层理化特性。主要研究结果和初步结论如下：(1)巴丹吉林沙漠湖泊水离子的年际变化较稳定,映射出湖泊补给源、补给途径等在近10年来变化不大。湖泊离子浓度的季节变化受湖泊地理位置的影响较大,但可以看出秋季出现相对高值,夏季次之,冬春两季较低。(2)湖泊盐度具有“腹地高边缘低”的分布规律。在巴丹吉林沙漠119个常年积水湖泊中,盐湖占65.5%,淡水湖和微咸水湖各占15.1%。南缘湖泊计31个,其中淡水湖占多一半,微咸水湖占三分之一；东缘和西北缘零星分布着8个微咸水湖和咸水湖；腹地湖泊80个,盐湖占九成。(3)湖泊面积具有“南小北大”的空间分布特点。南缘几乎均为面积小于0.1km2的湖泊,沙漠中少有的几个面积大于1km2的湖泊都出现在腹地,即湖泊TDS值与湖泊面积呈正相关,这可能与湖水补给-排泄的循环速率、总量有关。(4)湖泊水化学类型呈现出“南线北片”的明显差异。南缘淡水湖和微咸水湖大多以Cl·SO4-Na形式沿东北-西南一线分布。腹地湖泊离子组分总体上呈现不稳定的状态,不同水化学类型的湖泊以“片状”的形式集中出现,从东向西依次为SO4-Na型、Cl·CO3-Na或CO3-Na型、Cl-Na型湖泊。这种分布格局,与湖群下伏地下水的水化学特性有密切关系；时间、湖泊形态特征、水离子地球化学作用等因素可以影响到湖水中主要离子的百分含量。(5)诺尔图湖水垂直方向上,湖水理化特性分层最显著是春季(4月),夏季(7月)次之,秋季(10月)和冬季(1月)湖水相对均一,分层结构不明显。这是风速、气温、地下水补给等因素在不同季节下作用强度不同所致。更多还原

【Abstract】 The Badain Jaran Desert is famous for its unusual natural and humanities landscape, such as abrupt rare peaks, singing sand, lakes, magical springs and temples, which attracted domestic and foreign scholars’attention and research for a long time, especially how those lakes that in the desert were formed? But the issue had failed to resolve all the time. We thought that work in hydro chemical of the Badain Jaran Desert Lake was a basic task to know water quality of those lakes better. So perfect and added research on water quality in this area was help for solving the mechanism formation of the desert lakes.The paper mainly analysis spatiotemporal variations character of the Badain Jaran Desert lake, and the cause of its formation, then, make a qualitative explanation of its formation, which thanks to the scientific investigation of the Badain Jaran Desert, that sponsored by College of earth and environment science, Lanzhou University, united researchers of Gansu Desert control Research Institute and NingXia University, who collected plenty of first-hand data of the desert lakes form2009to2012. In this paper, firstly, we compared the water analysis result of September2009with1999and2010, also September2010, January, April, July2010, in order to understand the inter-annual changes of hydro chemical characters of Badain Jaran Desert Lake; Secondly, we made an overall research of spatial distribution features of those119lakes, that sampling in September2010; Thirdly, we chose an typical lake-Nuoertu, which sampling in April, July, October2011and January2012, for observation layered physical and chemical characteristic in seasons. The mainly research conclusions were as follows:(1)The inter-annual variability of ions in the Badain Jaran Desert lakes is stable, it means that there are no change on the recharge resource and ways. The seasonal change of lake ions is effected by the location of the lake, while we could find the high ion value appeared in autumn, and then in summer, the ion value is lower in winter and spring.(2) It shows "low edge high hinterland" of lake saltiness in Badain Jaran Desert. In September2010, there were119lakes in the desert totally, include65.5%salty lake,15.1%freshwater lake and15.1%weak saltwater. In another words, the edge of south of the desert had31lakes, which contains over half freshwater lake, one third weak saltwater lake; the edge of east and northwest of the desert laid8weak saltwater lake and saltwater lake; the inner desert had80lakes, which had salty lakes over90%.(3) The lake area expressed "big-north, small-south". Concretely speaking, lakes in the edge of south desert mostly were smaller than0.1Km2, while those that larger than Ikm2were all located in inner desert, it seems TDS was positively related with lake area, it was mostly related to rate and quality of supplies and discharge of groundwater.(4)The desert lake’s hydro chemical type present a pattern of "pieces-north, line-south". It means kind of Cl·SO4-Na freshwater lake or weak saltwater lake that lied in the edge of south desert just along a northeast to southwest line, several salty lake was Cl-Na. while lakes those lied in inner desert had a instability components of ion concentration. There were for types lake from east to west at least:SO4-Na, Cl·CO3-Na, CO3-Na, Cl-Na. Each type of lakes appeared intensively, just like four "piece" linked together. This huge difference between the two Lakes mostly affected by discharge of groundwater, and the geochemical process among ions in different evolution stage also can’t be neglected.(5) The Physical and chemical layered characters in April of Nuoertu in vertical was the most marked, the next is July, while October and January shows relatively homogeneous. The different characters of temperature and other water chemical in vertical lake water, is mainly caused by wind, temperature and discharge of groundwater or other factors.更多还原