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在普莱斯托时代中期,西伯利亚大陆的气候变化变得沉默
Alexander A Prokopenko1, Douglas F Williams, Mikhail I Kuzmin
1Department of Geological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA. sasha@geol.sc.edu
Nature
|July 5, 2002
概括
海洋同位素记录表明,在海洋氧同位素阶段12 (MIS 12) 和MIS 11之间发生了剧烈的气候转变. 然而,贝加尔湖的沉积物数据显示,气候对比度较弱,冰川在此期间减少.
科学领域:
- 古气候学 古气候学
- 四年纪地质学四年纪地质学
- 同位素地质化学 同位素地质化学
背景情况:
- 海洋同位素记录表明,在海洋氧同位素阶段12 (MIS 12) 和MIS 11 (480-380年前) 之间发生了显著的气候过渡.
- 这种过渡被解释为从严重的冰川期转变为温暖的间冰期,影响全球冰量,海平面和碳循环.
- 这种气候变化的规模令人费解,因为在这个时间段内预测的轨道强迫力很弱.
研究的目的:
- 使用来自贝加尔湖的连续沉积物记录,研究MIS 15a和MIS 11 (580-380 kyr前) 之间的气候动态.
- 为了比较这个时期的气候对比,与最近的冰川-冰川间周期在普莱斯托纪晚期.
- 为了评估在这段时间内山区冰川的程度.
主要方法:
- 来自西伯利亚贝加尔湖的连续沉积物核心的分析.
- 检查藻组合 (浮游生物和盆地生物) 用于古环境重建.
- 分析石质沉积物以推断环境条件.
主要成果:
- 贝加尔湖的记录显示了连续的冰河间条件,包括稳定的藻群和"冰河间"的MIS 15a到MIS 11之间的石化沉积物.
- 在MIS 12和MIS 11之间推断的气候对比度明显低于近期晚期普莱斯托时代冰川 - 冰川间过渡期间观察到的差异.
- 有证据表明,在MIS 15a到MIS 11期间,没有广泛的山地冰川.
结论:
- 在MIS 12和MIS 11之间的气候过渡比以前从海洋记录中推断的要少.
- 贝加尔湖为过去的气候变化提供了关键的陆地视角,挑战了仅基于海洋档案的解释.
- 这些发现表明,与普莱斯托时代晚期相比,普莱斯托时代中期的冰川 - 间冰川动态的模式不同.
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