导　　师： 高全洲

学科专业： 070501

授予学位： 硕士

作　　者： ;

机构地区： 中山大学

摘　　要： 粘土矿物通常在表生风化作用下形成，普遍存在于各类土壤和沉积岩中。粘土矿物作为化学风化过程中形成的次生矿物，对环境的变化极为敏感,因而土壤中粘土矿物的矿物成分、组合特征及其含量变化都记录了粘土矿物形成过程中气候环境因素的变化。 本文选择位于青藏高原的高寒草甸土壤和内蒙古的温带典型草原土壤作为研究对象，选择不同植被类型、母质、地貌部位的土壤剖面，进行高分辨率采样，通过对比两个研究区土壤粘土矿物的组合特征及含量、土壤机械组成、土壤有机碳等多项指标变化,分析各个指标间的相互关系，探讨不同草原生态系统的风化作用类型、气候特点，揭示粘土矿物在草原土壤中的环境指示意义。研究表明： （1）青藏高原研究区和内蒙古研究区各个土壤剖面粒度组成均以粉粒、砂粒为主，占总含量90/%之上，粘粒含量不足10/%，反映了研究区土壤发育程度较低，风化成土作用较弱。在青藏高原地区，受地形影响，班戈县山地坡麓土壤粘粒、粉粒含量明显大于山地山坡土壤的相应值；那曲县样地土壤粘粒、粉粒含量明显大于班戈县样地的相应值，土壤颗粒也更细，主要是受到植被类型的影响，与高山柳灌丛草甸较强的蓄水能力，较高的植被覆盖率有关。在内蒙古地区，苏尼特左旗荒漠化草原土壤的粘粒、粉粒含量随深度增加而升高，砂粒含量逐渐减少，反映了干旱、半干旱地区风蚀作用对土壤的改造；阿巴嘎旗典型草原的土壤粒度随深度变化不明显，地表土壤基本保持原来的粒径特征。 （2）受较低的年平均气温，较高的年平均降雨量，土壤湿度大，冻结时间长等气候环境因素的影响，青藏高原研究区SOC含量明显大于内蒙古研究区的相应值。班戈县山麓SOC含量明显大于山坡SOC含量，较高的粘粒含量对土壤有机碳的形成和稳定起到了一定保护作用。受温度、降雨量、植被类型等多个因素耦合作用的影响，那曲县SOC含量远远大于班戈县SOC含量。阿巴嘎旗的SOC含量明显大于苏尼特左旗的相应值，表明随着温度的增高和降水量的减少，SOC含量呈减少趋势。 （3）青藏高原研究区和内蒙古研究区的粘土矿物组成相似，均以伊利石为主，占总含量的70/%以上，其次为绿泥石、高岭石，基本不含蒙脱石。粘土矿物组合特征以及伊利石化学指数、伊利石结晶度值等多指标共同指示了研究区以物理风化为主，化学风化作用较弱的干冷气候特点。通过对比高寒草原土壤、森林草原土壤以及热带森林土壤中粘土矿物的组合特征变化，表明粘土矿物组合随气候条件变化具有明显的地带性分布特征，气候在控制化学风化作用过程中占主导因素，母岩性质、构造活动在控制化学风化作用中占次要因素。研究区土壤样品中全部检测出少量高岭石的存在，可能是风成沉积的结果，也可能是沉积岩经物理风化释放部分高岭石。 As secondary minerals during chemical weathering, clay minerals arecommonly found in various types of soil and sedimentary rocks, which areextremely sensitive to changes in the environment, so the combination ofcharacteristics of the clay minerals, mineral components and their contents changerecorded the clay minerals during the formation of a variety of changes inenvironmental factors from different angles. The article based on alpine meadow soil in the Qinghai-Tibet Plateau and theInner Mongolia steppe soil as the research objects and selected different vegetationtypes、parent material and topography parts of the soil profile, through comparing thetwo study areas combination of features and content, soil mechanical composition,soil organic carbon and many other indicators change by using high-resolutionsampling, analyzing the relationship between various indicators, then explore thedifferent grassland ecosystem type of weathering and climate characteristics,revealing the environmental significance of clay minerals on the grassland soil.Some conclusions are as follows: /(1/) The Qinghai-Tibet Plateau and Inner Mongolia soil profile of grain sizeare denominated mainly silt, above the90/%of the total content, but clay content lessthan10/%, which reflecting the low degree of soil development and the weakweathering and pedogenesis. In the Qinghai-Tibet Plateau region, Bangor County mountain slope foot of clay soil silt content was significantly greater than themountain slopes because of topography; the Naqu soil sticky silt content wassignificantly greater than the Bangor County plots，meanwhile soil is finer particles,which mainly due to the impact of the vegetation types, the alpine shrub meadowstrong water storage capacity and high vegetation coverage are two reasons. In theInner Mongolia region, Sunitezuoqi desert steppe soil increased with increasingdepth， but sand content decreased, reflecting soil transformation in the arid,semi-arid areas of wind erosion；however, the Abagaqi grassland soil particle sizevariation with depth is not obvious, the surface soil is almost the original particlesize characteristics. /(2/) The Qinghai-Tibet Plateau SOC content was significantly greater than theInner Mongolia because of lower annual average temperature, the higher the averageannual rainfall, soil moisture, and a longer freeze time. Bangor County foothills SOCstorage was significantly greater than the slope, which high clay content plays aprotective role in the formation and stabilization of soil organic carbon. By a numberof factors as temperature, precipitation, vegetation type coupling effects lead to SOCstorage Naqu County is far greater than the Bangor County. Moreover, the SOCstorage capacity of Abagaqi is significantly greater than Sunitezuoqi showed thatSOC storage capacity tended to decrease with the increase in temperature anddecrease in precipitation. /(3/) The main clay mineral composition are illite in the Qinghai-Tibet Plateauand Inner Mongolia, more than70/%of the total content，the others are chlorite,kaolinite, similar content, and essentially free of Smectite. The clay mineralassemblages characteristic, illite chemistry index /(ICI/) and the illite crystallinity /(IC/)shows the cold and dry climate characteristics, so study area are mainly physicalweathering and weak chemical weathering. By comparing the clay mineralscharacteristic changes of alpine grassland soil，forest grassland soil and tropicalforest soil, which indicating the clay mineral assemblages has obvious zonaldistribution characteristics, climatic conditions is the primary factor in control ofchemical weathering, tectonic activity and the nature of the parent rock are secondary factors, but still have important impact on the intensity of chemicalweathering. Two Study area soil samples are detected the presence of a small amountof kaolinite, these may be derived from eolian deposition, also may be sedimentaryrocks released some kaolinit by physical weathering.

关 键 词： 粘土矿物 粒度 土壤有机碳 化学风化 高寒草原

分 类 号： [S812.2]

领　　域： [农业科学] [农业科学] [农业科学]