【作者】 张福瑞；

【导师】 戴雪荣；

【作者基本信息】 华东师范大学 ， 自然地理学， 2006， 硕士

【摘要】 流域环境变化是当今国际上研究的一个重点和热点问题，本文对中国东部、长江下游这样一个季风气候明显、人类活动强度较大的地区开展这方面的研究。具体流域选取了巢湖地区杭埠河上游区域，通过对该流域表层土样及上游龙河口水库沉积柱样（ALE）的采集，在室内进行X衍射、粒度、环境磁学、营养盐元素等参数指标的实验分析，并结合水文资料，将沉积物中所记录的该流域过去环境变化信息与所收集到的历史文献记载相结合，重建了杭埠河上游近50年来流域环境变化的历史，探讨了建库近50年来人类活动（主要是农业活动）对流域环境的影响，具有典型代表意义。通过研究，本文得出以下结论和成果： （1） 通过对代表性沉积柱样ALE进行粒度及SCP分析，结合安徽火力发电量及径流资料，用粒度．径流方法成功建立了近50年来的年级分辨率的现代湖泊沉积年代序列。 （2） 水库沉积物能客观地记录湖泊环境的演化过程，结合磁性参数、平均粒径及人类活动分析，重建了该流域近50年来环境变化历史，并发现近50年来的沉积环境可以划分为五个阶段，各阶段特征如下：第一阶段（1958～1968年），由于相对较少的降水量及人类盲目垦荒的共同影响，沉积物颗粒较细，有较高的x_fd％值，且平均粒径较小，C／N值较低。第二阶段（1968～1976年）主要由于人类影响加剧，水土流失严重，致使本阶段沉积颗粒较粗，x明显增大，由于径流量也较大，大量的陆源碎屑物质被携带入库，C／N值出现高值。第三阶段（1976～1979年），本阶段由于极度干旱，沉积颗粒明显偏小，又由于强烈的蒸发浓缩，使得总氮总磷以及磁性矿物的含量都大大增加，均处于高值段。第四阶段（1979～1992年），由于人工整治，水土流失得以缓解，进入水库的泥沙大量减少，陆源碎屑物质也大大减少，C／N比值明显降低。第五阶段（1992～2003年），本阶段由于绿化造林水土流失减少，但在经济发展中没能处理好废弃物出现新的沉积来源，淤积现象仍很严重。 （3） 降雨和人类活动是影响本流域沉积的主要因素，本流域水源补给以降雨为主，而近50年来降雨的年际变化较大，降雨量出现丰、枯水交替出现的变化过程：降雨丰富的年份，径流量大，库区沉积物颗粒较粗，陆源生物碎屑物质较多：反之，降雨量少的阶段，颗粒较细，陆源生物碎屑物质较少。更多还原

【Abstract】 Catchment environmental changes, as one of the major and disputive subject internationally, is tackled in the paper, focusing on the estern part of China and the lower reaches of Yangtse River,a region characterized for the monson climate and the intensity of human activities. This paper selects Longhekou reservoir of Hangbu River catchment in Chaohu as study area. Samples, including surface soil and ALE core, were collected to obtain information about past environmental evolutions by means of environmental magnetism, grain size, X-ray and geochemical lements. By the help of water datum and comparing the information from the sediments with historical data, the influences of human activities in the past 50 years on the lake sediment are revealed. Through these analyzing and researching some conclusions were reached and acquired.(1)Through analyzing about grain size and SCP, combining Anhui fire power generation and runoff datum,it set up high-resolution age sequence in the past 50 years.(2) Sediment can record the evolvement of lake environment, Considering environmental magnetism and grain size etc. Longhekou reservoir can be devided five phases in the past 50 years. The first phase (1958~1968a): The grain sizes are small and the value of xfd% is high and the C/N is low because of relatively low rainfall and the human destroying activity; The second phase (1968~1976a): mainly influenced by human activity, the soil erosion is quite grave and the ecological environment is worsen.As a result, the grain sizes are coarse and the x becomes high in evidence. The C/N is also high because more fragments of terrestrial creatures are taken into reservoir by big rainfall. The third phase(1976~1979a): The grain sizes are very small because of drought and the contents of TP、 TN etc. are high due to strong vaporize. The fourthly phase (1979 - 1992a): the sediment became small and the C/N also falls because of the management of human.The fifthly phase (1992~2003a): the aggradations is still graveness because new sedimentary source.(3)The rainfall and the human activity are the major elements influencing the Hangbu River catchment deposition, and the former element is mainly water resources for the river. In the past fifty years the high flow year and the low flow year appear in turn with quite great difference in the amount of rainfall. There are also great differences in rainfall due to monsoon climate within a year with autumn receiving most of the rainfall resulting in floods. Because of the big current of runoff, the sediment grain sizes in the reservoir region are wide and the fragments of terrestrial creatures in the sediment are abundant in the high flow year. While in low flow year the grain sizes are small with little fragmental deposition of terrestrial creature.更多还原