Journal of Geographical Sciences ›› 2009, Vol. 19 ›› Issue (2): 225-238.doi: 10.1007/s11442-009-0225-7

• Climate and Environmental Change • Previous Articles     Next Articles

Sediment accumulation of Dianchi Lake determined by 137Cs dating

ZHANG Yan1,2, GAO Xiang1, ZHONG Zhenyu1, CHEN Jie2, PENG Buzhuo1   

  1. 1. School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210093, China|
    2. State Key Laboratory of Soil Sustainable Agriculture, Nanjing Institute of Soil Sciences, CAS, Nanjing 210008, China
  • Received:2008-03-24 Revised:2008-06-10 Online:2009-04-25 Published:2009-04-25
  • Supported by:

    National Natural Science Foundation of China, No.40771186; The Key Project of the State Key Laboratory of Soil Sustainable Agriculture, Nanjing Institute of Soil Sciences, Chinese Academy of Sciences, No.5022505

Abstract:

The water quality of Dianchi Lake declines quickly and the eutrophication is getting serious. To identify the internal pollution load of Dianchi Lake it is necessary to evaluate its sediment accumulation. Sedimentation rates of Dianchi Lake are determined by 137Cs dating. However, 137Cs vertical distribution in sediment cores of Dianchi Lake has special characteristics because Dianchi Lake is located on the southeast of the Qinghai-Tibet Plateau, the Kunming quasi-stationary front is over the borders of Yunnan and Guizhou where the specific precipitation is distributed. Besides 1954, 1963 and 1986 137Cs marks can be determined in sediment cores, a 137Cs mark of 1976 representing the major period of 137Cs released from China unclear test can be determined and used for an auxiliary dating mark. Meanwhile Dianchi Lake is divided into seven sections based on the water depth, basin topography, hydrological features and supplies of silt and the lakebed area of each section is calculated. The mean annual sedimentation rates for seven sections are 0.0810, 0.1352, 0.1457, 0.1333, 0.0904, 0.1267 and 0.1023 g/cm2a in 1963–2003, respectively. The gross sediment accumulation of the lake is 26.18×104 t/a in recent 17 years and 39.86×104 t/a in recent 50 years.

Key words: 137Cs dating, sediment accumulation rate, sedimentation section, Dianchi Lake