导　　师： 李福春;金章东

学科专业： 071012

授予学位： 硕士

作　　者： ;

机构地区： 南京农业大学

摘　　要： 对岩性稳定的/(或可以确定的/)单一流域的化学风化研究可以有效区分岩石／矿物风化作用和强度与气候要素/(气温、降水/)之间的制约关系,进而定量流域的化学风化速率。本文选取了处于季风气候敏感区/(青海湖/)和东南季风边缘区/(内蒙古岱海/)两个湖泊流域为研究对象,获取了两个湖泊盆地的不同季节水化学特征,并重点探讨了青海湖流域季节性化学风化速率和CO2消耗率。 对青海湖流域各种水样/(河水、地下水、雨水和湖水/)分季风前、季风期间、季风后三个季节进行了系统采样,并收集了流域内主要的岩石样品。通过对样品主要离子/(Ca2+、K+、Mg2+、Na+、Si、Sr、HCO3-、Cl-、SO42-、NO3-、F-/)的分析,利用推进模式量化了流域内的风化速率和CO2消耗率,并将分析结果和收集到的全球大河资料进行了对比。 对青海湖流域水化学数据分析表明：青海湖流域河水均显碱性,且其TDS含量高于流经喜马拉雅山和青藏高原南缘的河流。在季节变化上,除倒淌河外,青海湖流域四条主要河流TDS值季风后季节/(10月/)最高,季风季节/(7月/)最低。在河水离子组成上,流域内四条主要河流的离子以Ca2+和HCO3-为主,反映了碳酸盐风化输入的影响。通过对流域各种输入来源的量化发现,大气输入和碳酸盐风化是河水离子组成输入的两个同等重要的主要来源。此外,布哈河流域的蒸发盐溶解、沙柳河和哈尔盖河流域的硅酸盐风化也对河水组成有较大贡献。倒淌河河水成份由于流经老的湖相沉积,因而主要受盐岩输入控制。黑马河在季风季节,河水受碳酸盐风化和雨水输入的控制,而在季风前后,地下水对河水的补给作用可能比较大。 经过雨水的校正后,青海湖流域大气CO2净消耗率为35×103 mol／km2／yr。对比全球河流CO2消耗率,本研究区的值低于流经喜马拉雅山和青藏高原外 Tracing chemical weathering processes within a single catchment with stable or defined bedrocks can better understand the relationship between rock//mineral weathering and climatic parameters /(e.g. temperature, precipitation/) and quantify the rates of catchment chemical weathering. In this thesis, Lake Qinghai and Lake Daihai were chosen to study the seasonal hydrochemical characteristics of the two lake basin and further focused on the seasonal chemical weathering rates and CO2 consumption rates at Lake Qinghai catchment. Within the Lake Qinghai catchment, a variety of the water samples /(river water, groundwater, rainwater and Lake water/) were collected during three seasons /(pre-monsoon, monsoon, post-monsoon/), and rock samples were also collected. By the analysis of the main ions /(Ca2+、K+、Mg2+、Na+、Si、Sr、HCO3-、Cl-、SO42-、NO3-、F-/), the forward model was used to quantify the chemical weathering rate and CO2 consumption rate. Then, the results were used to make a comparison with the global data. The data of water chemistry in Lake Qinghai catchments shows that the river water are all very alkaline and have high concentrations of TDS compared to rivers draining the Himalayas and the southeastern Tibetan Plateau. Seasonal variations in the water chemistry shows that, except the Daotang River, the TDS concentration in high in October and low in July in the Lake Qinghai river system waters. The chemical composition of river water in the four large rivers is dominated by Ca2+and HCO3-, which represents the effect of carbonate weathering input. By quantifing the different sources, it is found that both of rock weathering and atmospheric input are important to the major ions of the Lake Qinghai catchment river waters. In addition, the evaporite input in Buha River, silicate weathering in Shaliu River and Hargai River are the second important sources to the river chemistry. The Daotang River water is dominated by halite input owing to its underlying old lacustrine sediments. The water

关 键 词： 季节变化 水化学 化学风化 消耗率 青海湖 岱海

领　　域： [天文地球] [天文地球]