奇特的节奏和早期南极冰河时代的快速结束
Tim E van Peer1,2,3, Diederik Liebrand4,5, Victoria E Taylor4,6
1University of Southampton, Waterfront Campus, National Oceanography Centre Southampton, Southampton, UK. t.e.vanpeer@leicester.ac.uk.
Nature communications
|December 5, 2024
概括
地球的气候历史,记录在深海氧气同位素中,揭示了偏心周期主要控制南极冰的体积. 斜度信号是不一致的,这表明偏心是冰河时代的主要驱动因素.
科学领域:
- 古气候学 古气候学
- 海洋地质 海洋地质学
- 地质时间学 (Geochronology)
背景情况:
- 地球的轨道周期 (斜率和偏心) 影响气候和地质时间尺度.
- 来自菌的氧同位素记录 (δ18Ob) 对于古气候重建至关重要,但显示了关于冰盖动态的相互矛盾信号.
- 之前对 δ18Ob 的解释导致了关于气候与冰盖相互作用的争议.
研究的目的:
- 为了呈现来自西北大西洋 (IODP Site U1406) 的高保真度 δ18Ob记录.
- 为了将这一记录与28-20亿年前的其他记录进行比较 (早期南极冰盖).
- 澄清偏心和斜度在加快早期南极冰的体积和理解冰盖行为的各自作用.
主要方法:
- 从IODP网站U1406.06获取一个高分辨率的 δ18 O 记录.
- 新的 δ18Ob记录与来自米奥森时代的现有古气候记录的比较.
- 对地球轨道周期 (离心率和斜率) 在 δ18 Ob信号上的印记进行分析.
主要成果:
- 异心的印记在 δ18Ob上是全球一致的,与不一致的斜度信号不同.
- 在南极早期的冰河时代,偏心是陆地冰块体积的主要节奏器.
- 南极早期的冰河时代,伴随着更大的偏心周期,容易迅速结束.
结论:
- 这项研究表明,偏心,而不是倾斜,是早期南极冰盖体积的主要驱动因素.
- 在大型冰盖中,强大的自我稳定性歇斯底里效应可以在变暖的情况下保持增长.
- 快速的冰河时代终结表明,冰盖融化阻力比模型模拟预测的要弱.
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