中文摘要：

湖滨岩心沉积相及磁学特性能够记录水动力、沉积环境和古气候等信息。选取博斯腾湖湖滨岩心沉积物为研究对象,应用环境磁学方法,并结合X衍射、粒度及有机质含量分析沉积环境变化过程。结果显示,湖滨沉积物以低矫顽力的亚铁磁性矿物为主导,颗粒较粗,磁铁矿是主要载磁矿物。在不同沉积相中,磁化率表现出不同,上部磁化率值较高,中部深色粉砂质泥层呈高值,富含有机质的泥炭土层磁性较弱,下部磁化率值降低,最下部沉积物颜色加深,磁化率值有所增加。X衍射显示沉积物以石英、长石等外源碎屑矿物为主,粒度以粉砂、砂为主,上部粗而下部细,中间波动变化。有机质含量在中部呈高值且波动明显,表明沉积环境的交替变化。通过不同深度岩性样品的磁性差异,以及粒度、有机质、岩心颜色对沉积动力的响应,指示湖滨岩心经历了滨浅湖相—湖沼浅水相—浅湖相的水文交替过程。

英文摘要：

The lakeshore sediment and its magnetic characteristics may suggest hydrodynamic conditions,sedimentary environment and paleoclimate.In this paper,we choose the samples of different lithology from the cores obtained at the Bosten lakeside for magnetic studies.Combined with the data of X-ray diffraction,grain size and TOC content,the depositional process was inferred.The magnetic minerals of the samples are dominated by ferrimagnetic minerals with low coercivity and rather coarse particle size.Magnetite is the main magnetic mineral in the sediment.In the samples of different lithology,magnetic susceptibility values show distinct differences.In the upper part of the core,the values are relatively high,while in the middle part of the core consisting of dark silty mud,the values are apparent high and vary vertically.However,the magnetism of the peat soil with high TOC matter is quite weak.In the lower part,the samples show low values of magnetic susceptibility.To the bottom,the color of the sediment turns to black and the susceptibility values increase.XRD analysis reveals that the sediment mainly consists of sands and silts of quartz and feldspar showing a coarsening upwards sequence in general with some opposite fluctuations.Organic matter of the middle part varies apparently,suggesting the shifting of the sedimentary environment.With the changes in magnetic properties in the samples of different lithology,and based on the response of grain size,organic matter and sediments color to sedimentary dynamics,we can tentatively infer that the lake has experienced a complicated history of sediment dynamic changes,reflected by alternating lakeshore facies,limnic facies and shallow lake facies.