在Neoproterozoic冰川化之后的极端风和浪潮
Philip A Allen1, Paul F Hoffman
1Department of Earth Sciences, ETH-Zürich, Sonneggstrasse 5, CH-8092 Zürich, Switzerland. philip.allen@erdw.ethz.ch
Nature
|January 15, 2005
概括
在古代海洋沉积物中发现的巨大的波浪波纹表明,在马里诺冰川结束时,极端的风和波浪. 这些发现为地球的"雪球地球"事件和古气候提供了洞察力.
科学领域:
- 古气候学 古气候学
- 沉积物学的沉积物学
- 地质物理学 地质物理学
背景情况:
- 原生代冰川代表了地球历史上严重的气候事件.
- "雪球地球"假说假设在马里诺冰川 (约6.35亿年前结束) 等冰川期间几乎存在全球冰盖.
- 主要冰川的终结意味着冰川迅速融化,海平面上升显著.
研究的目的:
- 为了研究在马里诺冰川之后海平面上升时形成的沉积物结构.
- 在这个关键的气候转型期间,重建古海洋学条件,特别是波浪和风的状态.
主要方法:
- 来自全球多个地区 (澳大利亚,巴西,加拿大,纳米比亚,斯瓦尔巴德) 的沉积物的平流图分析.
- 沉积结构的水力动力学分析被解释为巨大的波浪波.
- 根据物理原理重建波浪周期和风速.
主要成果:
- 发现了同类的巨浪波纹结构,在整个大陆的等级平面上.
- 水力动力学分析表明波浪周期异常长 (21-30秒).
- 重建的条件表明,在广的海洋盆地,风速持续高 (>20米/秒).
结论:
- 这些发现支持在海上后气候过渡期间出现极端风和浪的情况.
- 重建的条件为验证气候和海洋循环模型提供经验数据.
- 巨大的波浪作为"雪球地球"后果的独特古气候指标.
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