连续的50万年气候记录来自静脉石在魔鬼洞,内华达州
概括
来自内华达州魔鬼洞的古气候记录揭示了50万年的温度历史. 这个大陆记录挑战了米兰科维奇假设,表明内部气候系统的反驱动了冰川周期.
科学领域:
- 古气候学 古气候学
- 地质化学 地质化学
- 四年纪地质学四年纪地质学
背景情况:
- 对古气候档案的氧同位素 (delta(18) O) 分析提供了对过去温度和冰体积的洞察.
- 魔鬼洞石核心 (DH-11) 提供了一个独特的,连续的大陆古生物学记录.
研究的目的:
- 为了重建长期古气温记录来自内华达州的魔鬼洞.
- 为了将这一大陆记录与已建立的南极和海洋古气候档案进行比较.
- 调查普莱斯托纪冰川周期的驱动因素,并测试米兰科维奇假设.
主要方法:
- 氧同位素 (delta(18) O) 分析一个36厘米的静脉石核心 (DH-11).
- 使用21个复制的质谱系列日期进行时间测算.
- 魔鬼洞记录与沃斯托克冰芯和海洋三角洲记录的比较.
主要成果:
- 建立了一个连续50万年的古气温度记录.
- 该记录与沃斯托克的主要特征和海洋冰体积记录密切相匹配.
- 冰川周期的持续时间差异很大 (8万到13万年),这表明无周期性.
- 间冰河时期持续了大约2万年.
- 脱冰并不是主要由轨道阳光照射变化引发的.
结论:
- 魔鬼洞的古生物学温度记录挑战了米兰科维奇假设,认为它是普莱斯托纪冰川周期的唯一驱动因素.
- 观察到的冰川周期动态与地球气候系统 (大气层-冰盖-海洋) 内的内部非线性反相一致.
- 主要的气候变化似乎是无周期性的,是由复杂的系统相互作用驱动的,而不是仅仅是外部轨道强迫.
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