校准了波斯纪末期的大规模灭绝事件
Shu-zhong Shen1, James L Crowley, Yue Wang
1State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Nanjing 210008, China. szshen@nigpas.ac.cn
概括
波斯纪末期的大规模灭绝,地球上最严重的生物多样性危机,在2.52.2亿年前刚刚达到顶峰. 这场灾难性的事件,以快速的碳同位素外流和广泛的野火为标志,很可能是由大规模的温室气体释放引起的.
科学领域:
- 古生物学的古生物学
- 地质时间学 (Geochronology)
- 同位素地球化学 同位素地球化学
背景情况:
- 波斯纪末期的大规模灭绝代表了地球历史上最严重的生物多样性危机.
- 了解这一事件的确切时间和原因对于理解过去的环境变化和未来的风险至关重要.
研究的目的:
- 为了准确地确定末波斯纪大灭绝事件的日期.
- 调查与灭绝相关的环境条件和潜在触发因素.
主要方法:
- 收集和分析来自中国南方沉积区的地质年代,同位素 (δ(13) C) 和生物层状图数据.
- 高精度的- (U-Pb) 年龄测定.
- 对沉积层的分析,以寻找野火的证据 (木炭,煤灰).
主要成果:
- 灭绝的峰值是在252.28 ± 0.08万年前之前的时间.
- 在9万年内发生了显著的δ(13) C下降,随后是持续≤20,000年的-5‰的快速游览.
- 灭绝间隔不到20万年,在海洋和陆地生态系统中同步,有广泛野火的证据.
结论:
- 波斯纪末期的大规模灭绝是一个具有精确地质年代的快速事件.
- 这次灭绝与显著的碳循环扰乱和陆地燃烧相吻合.
- 热性二氧化碳和/或甲的大规模释放被认为是这种灾难性灭绝的主要原因.
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