|ZHANG Tingxi,WEN Yingting,DONG Danping,WANG Guoxiang.Grain size features and sedimentary environment of surficial sediments in the northwest Lake Taihu. J. Lake Sci.2018,30(3):836-846. DOI:10.18307/2018.0325
|关键词: 太湖西北部 表层沉积物 粒度 空间分布 沉积环境
|Grain size features and sedimentary environment of surficial sediments in the northwest Lake Taihu
ZHANG Tingxi1,2,3, WEN Yingting1, DONG Danping1, WANG Guoxiang1
1.School of Environment, Nanjing Normal University, Nanjing 210023, P. R. China;2.Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, P. R. China;3.Jiangsu Key Laboratory of Material Cycle & Pollution Control, Nanjing 210023, P. R. China
|Sixty-four surficial sediment samples taken along the northwest of Lake Taihu were analyzed by particle size analysis. Combined with particle size parameter calculation and cluster analysis, the characteristic of particle size distribution and the sedimentary types of surficial sediments were discussed. The results show that the sediments had average particle sizes of 4.0-58.7 μm, and average grain mass fractions of 7.19% for clay, 81.81% for silt, and 11.00% for sand, respectively. Silt and sand are the dominant components in the sediments. There are more coarse particles in the western coastal area and more fine particles in the northern lake. The west bank of the study area was characterized by the enrichment of coarser deposition, indicating strong hydrodynamic conditions and nearby source. The frequency curves of sediments in the northern part of Lake Taihu are wide with the peak in the fine grain level, while that of the sediments in the western area are single-peaked and the grain size was coarse; the grain size of sediments in the estuary was coarser than that of river channel. The results of Q-type cluster analysis show that the study area can be divided into four types of sedimentary areas, among which three types of areas are typical. The first type of sedimentary area is located in the west bank of Lake Taihu with relatively coarse grain size. The second type sedimentary area is in the estuary with the coarsest particles. the third type of sedimentary area is located in the Liangxi River where cyanobacteria bloom occurs frequently, and its clay content was extremely high, indicating that the grain size of the sediments may be related to the lake pollution condition.
|Key words: Northwest Lake Taihu surface sediments particle size spatial distribution sedimentary environment