气候对轨道强迫的反应穿过了奥利古森-米奥森的边界
J C Zachos1, N J Shackleton, J S Revenaugh
1Earth Sciences Department, Center for Dynamics and Evolution of the Land-Sea Interface, University of California, Santa Cruz, CA 95064, USA. jzachos@es.ucsc.edu
概括
这项研究揭示了米兰科维奇周期影响了奥利古纪晚期-米奥纪早期的气候和海洋化学. 一个显著的冰川事件 (Mi-1) 与一个罕见的轨道配置相吻合,有利于南极冰盖的扩张.
科学领域:
- 古气候学 古气候学
- 海洋学 海洋学 海洋学
- 气候科学 气候科学
背景情况:
- 末奥利戈纪-初米奥纪气候和海洋碳化学对于理解长期气候动态至关重要.
- 众所周知,米兰科维奇周期在各种时间尺度上影响地球的气候.
研究的目的:
- 为了分析气候和海洋碳化学的光谱特性,在550万年的时间里.
- 调查轨道变化与气候事件 (包括冰川) 之间的关系.
主要方法:
- 来自西赤道大西洋的深海核心的光谱分析.
- 跨越550万年的时间重建 (我的).
- 检查米兰科维奇频率的方差.
主要成果:
- 气候变异集中在所有米兰科维奇频率.
- 在406千年 (ky) 偏心带 (20-23.4 Ma) 中的异常光谱功率.
- 在怀疑的低温室气体水平 (21.7-23.0 Ma) 期间,在125和95-ky频段显著的光谱功率.
- 米-1 冰川 (大约. 23 Ma) 与轨道一致性 (斜度节点,离心率最小) 相关.
- 延长的时间 (大约. 200 ky) 的低季节性轨道有利于南极冰川的扩张.
结论:
- 米兰科维奇周期显著影响了奥利古纪晚期和米奥纪早期的气候和海洋碳化学.
- 轨道配置在引发主要气候事件中发挥了关键作用,例如Mi-1冰川.
- 低温室气体水平可能放大了对气候的轨道强迫作用.
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