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纹层计年与137Cs、210Pb法对比研究东北二龙湾玛珥湖现代沉积速率

游海涛1，刘强2，刘嘉麒2，储国强2，汉景泰2   

  1. 1.吉林大学 地球科学学院，长春 130061；2.中国科学院 地质与地球物理研究所，北京 100029
  • 收稿日期:2006-09-19 修回日期:1900-01-01 出版日期:2007-01-26 发布日期:2007-01-26
  • 通讯作者: 游海涛

A Comparative Study on Model Sedimentation Rates with Varve Dating,137Cs and 210Pb Dating in Erlongwan Maar Lake, NE China

YOU Hai-tao1, LIU Qiang2, LIU Jia-qi2, CHU Guo-qiang2, HAN Jing-tai2   

  1. 1.College of Earth Sciences, Jilin University, Changchun 130061,China；2.Institute of Geology and Geophysics, Chinese Academy of Science,Beijing 100029,China
  • Received:2006-09-19 Revised:1900-01-01 Online:2007-01-26 Published:2007-01-26
  • Contact: YOU Hai-tao

摘要： 通过对东北二龙湾玛珥湖顶部无扰动岩心显微研究，证明此岩心发育有良好的年纹层。据精确统计，0~5.5 cm间为36个年纹层，纹层计年的误差为4％~7％，年纹层厚度为1.1~2 mm不等，平均沉积速率为1.53 mm/a，5.5 cm处对应于1965年。而二龙湾沉积物（从6.5 cm到5.5 cm)岩心的137Cs比活度值急剧增加,从（4.67±0.29） dpm/g增加到（12.06±0.47） dpm/g，在5.5 cm处有一个较为明显的蓄积峰值，这一峰值被确认对应为1963年全球137Cs散落的高峰期。另外据210Pbex比活度CIC模式，5.5 cm处约为1962年，这和137Cs比活度曲线的1963年时标相一致。印证了纹层计年的精确性，完全可以建立高分辨率时间序列。

关键词: 二龙湾玛珥湖, 纹层计年, 137Cs、210Pb定年

Abstract: Detailed investigations were carried out on the upper undisturbed sediments from Erlongwan maar lake, NE China, which are better annually laminated sediments (varve). Varve couple appears as darkand lightcoloured layers. Based on varve dating of large thin sections under microscope, 36 varve couples, with 4％~7％ discrepancy , 1.1~2 mm varve thickness and 1.53 mm/a rate of sedimentation were found in the upper part of the core (0~5.5 cm), and 5.5 cm correlates to the year of 1965. However, Radiometric dating shows that the highest 137Cs activity appears at 5.5 cm depth , assumed to correlate to the 1963 maximum of emission due to the nuclear bomb testing. 137Cs activities increase quickly from 6.5 cm to 5.5 cm (from 4.67±0.29 dpm/g to 12.06±0.47 dpm/g ).In addition , By calculating of 210Pbex (CIC) , 5.5 cm depth corresponds with the 1962. As a result, 210Pbex (CIC) and 137Cs dating show a good agreement with the varve dating. Varve dating is exact and varve sediments can offer an effective means of acquiring highquality palaeoenvironmental records.

Key words: Erlongwan maar lake, varve dating, 137Cs and 210Pb Dating

中图分类号: 

  • P533
[1] 刘玉英,刘嘉麒,汉景泰. 吉林辉南二龙湾玛珥湖12.0 ka B.P.以来孢粉记录与气候变化[J]. J4, 2009, 39(1): 93-0098.
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