极地研究

极地研究 ›› 2003, Vol. 15 ›› Issue (3): 207-213.

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34000年以来南极汞沉降通量的估算

尹雪斌;孙立广;谢周清   

  • 出版日期:2003-09-30 发布日期:2003-09-30

AN ASSESSMENT OF VARIATIONS IN MERCURY DEPOSITION TO ANTARCTICA OVER THE PAST 34000 YEARS

  • Online:2003-09-30 Published:2003-09-30

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摘要：

本文统计分析了南极DomeC冰芯中汞含量和降水指征参数δ1 8O值、1 0 Be浓度的关系 ,发现冰芯中Hg含量和δ1 8O值、1 0 Be浓度变化一致 ,表明DomeC冰芯汞含量受到冰雪积累率的影响 ,而且三者变化的高度同步性可能说明其原始驱动力也是一致的 ,从而冰芯中Hg含量可以和1 0 Be浓度一样作为冰雪积累率估算的替代性指标。此外 ,利用δ1 8O数据 ,系统估算了 340 0 0年以来南极汞沉降通量的变化。结果表明 ,DomeC冰芯汞沉降通量在末次冰盛期 (LGM)最高 ,为 3.80pgcm- 2 a- 1 ,约是全新世汞沉降通量 ( 1 .0 8pgcm- 2 a- 1 )的 3.5倍 ,该变化可能主要受到汞的自然排放量影响。

关键词: 汞沉降通量;降水速率;末次冰盛期;全新世;南极冰芯

Abstract:

Comparing the variation of the Hg concentrations in 14 subsamples from Antarctic Dome C ice core (Vandal et al., 1993) with the precipitation proxies such as δ 18 O values and 10 Be concentrations in the Dome C ice more, we found a significant correlation between Hg concentrations and δ 18 O values, 10 Be concentrations. And this clearly indicates that the accumulation rate in Dome C is one of the key factors to the variations of Hg concentrations. Therefore, Hg concentrations in ice core can be used as a proxy of precipitation rate. In this paper, we reassess the variations in mercury deposition flux in Antarctica over the past 34,000 years on the base of the high resolution δ 18 O values, which can be used as a good proxy reconstructing the precipitation rates. In our results, the highest mercury deposition flux is about 3.80pg cm -2 a -1 during the Last Glacial Maxium (LGM), as high as 3.5 times of the mercury deposition flux (about 1.08 pg cm -2 a -1 ) in Holocene. And this is because of the fluctuations in natural mercury emissions such as the oceanic biological emission.