森林砍伐后的区域气候反导致了在波斯末危机期间的二重周期C-S周期扰动
Jianbo Chen1, Binjian Lu1,2,3, Longye Du2,3
1State Key Laboratory for Vegetation Structure, Function and Construction (VegLab), Institute of Palaeontology, Yunnan Key Laboratory of Earth System Science, Yunnan University, Kunming 650500, China.
概括
珀米亚-特里亚斯纪的灭绝事件
科学领域:
- 古气候学 古气候学
- 地质化学 地质化学
- 古生物学的古生物学
背景情况:
- 珀米亚-特里亚斯 (P-Tr) 过渡 (约252万年前) 标志着地球最严重的生物危机,历史上与西伯利亚陷火山活动有关.
- 之前的研究推断全球碳 (C) 和硫 (S) 循环扰乱主要来自海洋记录,陆地数据有限.
- 证据表明,陆地生态系统发生了双重崩,这就质疑了单一的,同步的全球强迫.
研究的目的:
- 通过古热带记录,研究P-Tr过渡期间的陆地碳和硫循环扰乱.
- 评估火山硫酸盐气溶与陆地生态系统崩在推动P-Tr危机中的作用.
- 评估不同度的陆地生态系统崩和生物地化学循环扰动的同步性.
主要方法:
- 从中国西南的一个泥炭地钻芯 (HK-1) 中分析了质多重硫同位素 (δ34Spy 和 Δ33S) 和散装有机碳同位素 (δ13Corg).
- 解释同位素特征以重建陆地硫源和碳循环动态.
- 将发现与现有的高度陆地记录 (例如,悉尼盆地) 进行比较,以评估跨度同步性.
主要成果:
- 确定了硫同位素变化的不同阶段,在P-Tr过渡过程中 δ34Spy显著下降,表明陆地硫酸盐流入增加.
- 较小的正值 Δ33S 值表明平流层火山产硫酸盐在观察到的硫异常中起了很小的作用.
- δ13Corg, δ34Spy和 Δ33S 变化支持卡泰西亚植物群的灾难性崩,导致气候变化加剧和硫酸盐释放.
结论:
- 西南中国的陆地生态系统崩和相关的碳硫循环扰乱发生在海洋灭绝后不久,并在更高度地区发生了类似事件.
- 陆地生态系统崩和跨度的生态化学扰动的双重性质挑战了P-Tr危机的单一全球火山驱动因素的假设.
- 区域森林砍伐及其对气候变化和硫酸盐释放的级联影响,叠加于全球生物地球化学扰乱,是地球上有记录以来最大危机的关键因素.
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