• 研究论文 •

季风边缘区湖泊表层沉积物粒度组分分布特征与影响因素

1. 1. 内蒙古大学环境与资源学院,呼和浩特 010021
2. 内蒙古大学环境地质研究所,呼和浩特 010021
3. 北京师范大学环境演变与自然灾害教育部重点实验室,北京 100875
4. 北京师范大学地表过程与资源生态国家重点实验室,北京 100875
• 收稿日期:2015-11-19 修回日期:2016-02-25 出版日期:2016-04-20 发布日期:2016-04-27
• 作者简介:

作者简介：郭晓阳（1992- ）,女,内蒙古四子王旗人,硕士,研究方向为环境变化。E-mail: 1052049534@qq.com

• 基金资助:
国家自然科学基金项目（41562009,41162004,41271207）;内蒙古教育厅高等学校青年科技英才计划（NJYT-14-A01）

Within-lake distributions of grain-size components and environmental implications based on the survey of lake surface sediment of Chinese monsoon marginal area

Xiaoyang GUO1,2(), Wei WANG1,2(), Guoliang WANG1,2, Lina LIU1,2, Yuzhen MA3,4, Jiang HE1,2

1. 1. College of Environment and Resource, Inner Mongolia University, Hohhot 010021, China
2. Institute of Environmental Geology, Inner Mongolia University, Hohhot 010021, China
3. Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education of China, Beijing Normal University, Beijing 100875, China
4. State Key Laboratory of Earth Surface Process and Resource Ecology, Beijing Normal University, Beijing 100875, China
• Received:2015-11-19 Revised:2016-02-25 Online:2016-04-20 Published:2016-04-27

Abstract:

In this paper, within-lake grain-size components distribution was disclosed and its relationship to the controlling and influencing environmental factors were explored, to present bases for interpretation of core grain-size data. Specifically, 139 lake surface sediments were achieved from 68 lakes and reservoirs in the Inner Mongolia Autonomous Region, Gansu Province and Ningxia Hui Autonomous Region. The grain-size of surface sediments was measured using Microtrac S3500 particle size analyzer, and the grain-size components were fitted and partitioned using lognormal distribution function. Correlation analysis and ordination analysis including detrended component analysis (DCA) and redundancy analysis (RDA) were used to analyze the relationships between grain-size components distribution and influencing factors, including water depth (De), the distance to shoreline (Ds), the distance to river mouth (Dr), the ratio between the distance to shoreline and the lake's radius (Ds/R), and the ratio between the lake's radius and the distance to river mouth (R/Dr). These factors can reflect the re-suspension caused by wave action (De), the transport of shoreline clastic deposit (Ds and Ds/R), the riverine clastic deposition and erosion process (Dr), and the overall influence of riverine clastic deposition under specific hydraulic conditions (R/Dr). Thus, the fitting and partitioning yields six components (i.e., C1: 0.4-1.9, C2: 2.0-12.0, C3: 17.0-58.0, C4: 70.0-150.0, C5: 170.0-500.0 and C6: >600.0 μm). The grain-size components of the samples near lake center mainly contain clay (C1), fine silt (C2) and medium-to-coarse silt (C3). The grain-size components of the samples in the transitional area mainly include medium-to-coarse silt (C3) and fine sand (C4). The grain-size components of samples near the shoreline mainly contain medium-to-coarse sands (C5). The results of scatter plot show that the R/Dr is extremely significant positively correlated with the C4 (n=139, R=0.280), C5 (n=139, R=0.273) and C6 (n=139, R=0.255), and significant negatively correlated with the C2 (n=139, R=0.233), suggesting river transportation and the hydraulic conditions is the major factor influencing the grain-size distribution of lake surface sediment. In addition, the factor of Ds/R shows extremely significant positive correlations with C3 (n=139, R=0.265) and extremely significant negative correlations with C5 component (n=139, R=0.299), suggesting that the relative location of the sample site to shoreline is the secondary influencing factor. Significant correlation was also found between the De and the C1, indicating that the water depth related wave action energy was also a factor influencing the distribution of clay components. The RDA results support those of the scatter plot and further disclose the relationship between the variables and the environment factors. That is, RDA results show that the R/Dr (F=7.20, P=0.0020) and the Ds/R (F=4.96, P=0.0120) are statistically correlated to the spatial distribution of grain-size of lake sediments. C4, C5 and C6 have a small angle with the positive vector of R/Dr, suggesting that the R/Dr is positively correlated with C4, C5 and C6. C3 has a small angle with the positive vector of Ds/R, suggesting the Ds/R is positively correlated with C3. Furthermore, the box plot comparisons of the grain-size component percentages between the lakes with inflow rivers and the lakes without inflow rivers suggest that, the river input and the related resuspension process control or influence the grain-size distribution, resulting in the enrichment of the clay and fine silt in the lake center. So the fractions of the riverine clay and fine silt in the lake surface sediment and associated environmental implications should arouse much attention.