在过去的5万年中,14C活动和全球碳循环的变化
K Hughen1, S Lehman, J Southon
1Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA 02543, USA. khughen@whoi.edu
Science (New York, N.Y.)
|January 13, 2004
概括
这项研究使用海洋钻井计划核心校准放射性碳 (14C) 时间尺度,长达5万年. 调查结果显示,在最后一个冰川时期,有显著的14C变化,与地磁事件和海洋碳循环变化有关.
科学领域:
- 古气候学 古气候学
- 地质时间学 (Geochronology)
- 通过放射性碳测年法进行测年.
背景情况:
- 放射性碳 (14C) 时间表对于重建过去的气候和事件至关重要.
- 超过3万年的14C时间尺度的高分辨率校准是有限的.
- 地磁场强度的变化和海洋碳循环的动态可以影响14C水库的年龄.
研究的目的:
- 为了建立放射性碳 (14C) 时间尺度的高分辨率校准,回到5万年前.
- 为了调查在最后一个冰川时期14C活动大幅变化的原因.
主要方法:
- 放射性碳 (14C) 测量了来自卡里亚科盆地的海洋钻探计划核心.
- 卡里亚科盆地核心时间表与格陵兰冰盖项目2 (GISP2) 年层计数时间表的相关性.
- 独立的放射测年法用于校准验证.
- 地化学盒模型模拟.
主要成果:
- 一个强大的,高分辨率的放射性碳 (14C) 时间尺度校准在现在之前达到了5万年.
- 在最后一个冰河时期重建了显著的14C活动变化.
- 这些变化与地磁场强度最小值 (拉尚,莫诺湖) 和宇宙原核峰值相关.
结论:
- 在14C生产速度的地磁调节变化是观察到的14C变化的主要驱动因素.
- 冰川时期的深海通风和全球碳循环的变化可能导致重建的14C波动.
- 该研究为古气候研究提供了准确和扩展的放射性碳 (14C) 时间表.
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