孔腔流体对冰川海洋温度和氧同位素组成的约束
1D. P. Schrag, Department of Geological and Geophysical Sciences, Princeton University, Princeton, NJ 08544-1003, USA. G. Hampt, Institute of Marine Sciences, University of California, Santa Cruz, CA 95064, USA. D. W. Murray, Department of Geological Sciences, Brown University, Providence, RI 02912, USA.
概括
在最后一个冰川最大期,海洋温度更冷. 对热带大西洋孔液和藻中氧气同位素的分析显示,深水温度下降了4°C,这有助于气候重建.
科学领域:
- 古代海洋学 古代海洋学 古代海洋学
- 海洋地球化学 海洋地球化学
- 气候科学 气候科学
背景情况:
- 重建过去的海洋温度对于理解气候动态至关重要.
- 海洋沉积物和化石中的氧同位素作为过去气候条件的有价值的代理物.
- 最后的冰川最大值 (LGM) 代表了全球冷却的重要时期.
研究的目的:
- 为了确定LGM期间在热带大西洋的深水温度.
- 评估冰体积变化对氧同位素记录的贡献.
- 为了协调不同古气候代理之间的差异.
主要方法:
- 从深海沉积物核心的孔液中分析氧气同位素组成 (delta18O).
- 测量delta18O在盆地甲中的含量.
- 孔流体和藻类数据与现有的古气候记录的整合.
主要成果:
- 在热带大西洋的海水delta18O在LGM期间比现在高出0.8±0.1每毫米.
- 这种较高的比率,再加上类动物的数据,表明在LGM期间,热带大西洋的深水温度降低了4°C.
- 估计全球冰体量对delta18O变化的贡献为每毫升1.0.
结论:
- 在LGM期间,深海循环和温度显著不同.
- 这些发现有助于将古海洋学数据与其他气候代理数据协调起来.
- 这项研究完善了我们对过去冰川时期热带大西洋海洋学的理解.
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