• 论文 •

### Anthropogenic Effect on Deposition Dynamics of Lake Sediments Based on 137Cs and 210Pbex Techniques in Jiuzhaigou National Nature Reserve, China

LIANG Kangkang, HU Xinxin, LI Shiguang, HUANG Chengmin, TANG Ya

1. College of Architecture and Environment, Sichuan University, Chengdu 610065, China
• 收稿日期:2012-10-31 修回日期:2013-02-27 出版日期:2014-01-27 发布日期:2014-01-28
• 通讯作者: HUANG Chengmin,cmhuangscu@gmail.com;TANG Ya,tangya@scu.edu.cn E-mail:cmhuangscu@gmail.com;tangya@scu.edu.cn
• 基金资助:

Under the auspices of Programme of Introducing Talents of Discipline to Universities (the 111 Project) (No. B08037), National Key Technology R&D Program of China (No. 2012BAC06B02)

### Anthropogenic Effect on Deposition Dynamics of Lake Sediments Based on 137Cs and 210Pbex Techniques in Jiuzhaigou National Nature Reserve, China

LIANG Kangkang, HU Xinxin, LI Shiguang, HUANG Chengmin, TANG Ya

1. College of Architecture and Environment, Sichuan University, Chengdu 610065, China
• Received:2012-10-31 Revised:2013-02-27 Online:2014-01-27 Published:2014-01-28

Radionuclide dating techniques characterized by 137Cs and 210Pbex have recently been applied in the study of lake sediments around the world. In this study, a chronological series of sediment cores was established based on 137Cs and 210Pbex analyses along with the evaluation of sediment properties, such as particle size distribution, total organic carbon (TOC), carbonate content, and acid-insoluble residue, to study sediment accumulation rates, sediment sources, and responses to human activities in the Jiuzhaigou National Nature Reserve in southwestern China. In terms of the particle size distribution of sediments, silt content was the highest, and clay and sand contents were relatively low. The sediments displayed high TOC contents because of the significant amounts of vegetation grown in the lakes. The carbonate content was also high due to the overall geological background of carbonates in Jiuzhaigou. Carbonate content tended to decline from top to bottom in the sediment cores, whereas the acid-insoluble residue tended to increase. These results suggested that the depth variation of the environmental parameters of the sediments in two lakes in Jiuzhaigou would correspond to each other. The results indicated that the sediment rate of Jiuzhaigou was generally high with strong siltation, indicating that serious soil loss was induced by intensive human activities in the basin over the past decades. The increases in the mass accumulation rate, contents of acid-insoluble residue, and mean particle size during the periods of 1840-1900s, late 1930s-early 1950s, 1966-1978, and 2003-2006 revealed the occurrence of severe soil and water loss as a result of extensive agricultural expansion, large-scale deforestation, and road construction in Jiuzhaigou. The deposition rate and the properties of lacustrine sediments could reflect the significant impact of human activities on lake sedimentation during Jiuzhaigou’s history.

Abstract:

Radionuclide dating techniques characterized by 137Cs and 210Pbex have recently been applied in the study of lake sediments around the world. In this study, a chronological series of sediment cores was established based on 137Cs and 210Pbex analyses along with the evaluation of sediment properties, such as particle size distribution, total organic carbon (TOC), carbonate content, and acid-insoluble residue, to study sediment accumulation rates, sediment sources, and responses to human activities in the Jiuzhaigou National Nature Reserve in southwestern China. In terms of the particle size distribution of sediments, silt content was the highest, and clay and sand contents were relatively low. The sediments displayed high TOC contents because of the significant amounts of vegetation grown in the lakes. The carbonate content was also high due to the overall geological background of carbonates in Jiuzhaigou. Carbonate content tended to decline from top to bottom in the sediment cores, whereas the acid-insoluble residue tended to increase. These results suggested that the depth variation of the environmental parameters of the sediments in two lakes in Jiuzhaigou would correspond to each other. The results indicated that the sediment rate of Jiuzhaigou was generally high with strong siltation, indicating that serious soil loss was induced by intensive human activities in the basin over the past decades. The increases in the mass accumulation rate, contents of acid-insoluble residue, and mean particle size during the periods of 1840-1900s, late 1930s-early 1950s, 1966-1978, and 2003-2006 revealed the occurrence of severe soil and water loss as a result of extensive agricultural expansion, large-scale deforestation, and road construction in Jiuzhaigou. The deposition rate and the properties of lacustrine sediments could reflect the significant impact of human activities on lake sedimentation during Jiuzhaigou’s history.