快速的冰川化和两阶段的海平面陷入最后的冰川极限
Yusuke Yokoyama1,2,3, Tezer M Esat4,5, William G Thompson6
1Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan. yokoyama@aori.u-tokyo.ac.jp.
Nature
|July 27, 2018
概括
大堡礁的海平面下降了20米,随后迅速上升. 这为从冰河时代过渡到温暖时期的气候模型提供了关键数据.
科学领域:
- 古气候学
- 四年纪地质
- 海洋学
背景情况:
- 最后的冰川最大期是地球上最冷的时期,其特点是大气中的二氧化碳和海面温度较低.
- 全球平均海平面 (GMSL) 在大约31,000年前显著下降,在万年脱冰期之前.
- 了解LGM-Holocene过渡对于完善气候模型和预测未来气候变化至关重要.
研究的目的:
- 准确确定大堡礁在LGM-Holocene过渡期间海平面变化的时间和程度.
- 使用区域海平面数据来限制GMSL和冰盖动态模型.
- 为改善过去和未来气候变化的气候模型提供可靠的数据.
主要方法:
- 从大堡礁架边缘发现的珊瑚化石和珊瑚藻类组合的分析.
- 这些化石组合的放射测年确定了海平面波动的精确时间表.
- 应用冰川静态模型从区域相对海平面数据中推导GMSL.
主要成果:
- 在21900年至20500年前,相对海平面下降了大约20米,相对于现代海平面下降了-118米.
- 在这种下降之后,相对海平面以每年3.5毫米的平均速度上升了大约4000年.
- 估计GMSL的低点为-125到-130米,而LGM的高峰是在大约20500年前.
结论:
- 大堡礁经历了海平面大幅下降和随后的快速上升,
- 这些发现提供了海平面变化的高分辨率记录,
- 获得的GMSL数据完善了我们对LGM-Holocene过渡的理解,改善了气候建模的约束.
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