Changes in the global carbon cycle occurred as two episodes during the Permian–Triassic crisis
Changes in the global carbon cycle occurred as two episodes during the Permian–Triassic crisis
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DOI：
10.1130/g24224a.1
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发表时间：
2007-12
期刊：
影响因子：
5.8
通讯作者：
S. Xie;R. Pancost;Junhua Huang;P. Wignall;Jianxin Yu;Xinyan Tang;Lin Chen;Xianyu Huang;X. Lai-X.
中科院分区：
文献类型：
--
作者：
S. Xie;R. Pancost;Junhua Huang;P. Wignall;Jianxin Yu;Xinyan Tang;Lin Chen;Xianyu Huang;X. Lai-X.
海洋，大气和陆地变化的同时代记录是至关重要的，以了解全球大规模灭绝的模式和原因跨越二叠纪-三叠纪边界（PTB）。然而，不同环境中的变化之间的关系在很大程度上仍然不清楚，主要是由于与不同记录之间的相关性有关的挑战。本文将中国南方梅山PTB剖面的海洋碳同位素记录与海洋和陆地沉积物中记录的环境和生物事件进行了比较。时间尺度的碳酸盐碳同位素表现出两个逐渐的主要变化，在梅山的PTB，这些都是重复的特提斯洋周围的其他地方。这两个转变与两个事件的增强陆地风化表示的丰度增加13 C-富集moretanes相对于Hopanes和一个升高的丰度的黑碳碎片。之前报道的PTB的关键海洋事件，包括透光带真石漆，动物群的大规模灭绝和蓝藻的扩张，也发生了两个事件，与负δ 13 C值的逐步转变和风化作用的增强相一致。可复制事件的时间顺序表明，生物危机是海洋和大陆系统长期和偶发变化的结果，并反对外星影响作为主要原因。
Coeval records of ocean, atmosphere, and terrestrial change are crucial to understanding the pattern and causes of global mass extinction across the Permian-Triassic boundary (PTB). However, relationships among changes in different settings remain largely unclear, primarily due to the challenges associated with the correlation among disparate records. Here we compare marine carbon isotopic records with marine and terrestrial environmental and biotic events recorded in sediments from the Meishan PTB section of south China. Time-scaled carbonate carbon isotopes exhibit two gradual major shifts across the PTB at Meishan, and these are duplicable elsewhere around the Tethys Ocean. The two shifts are associated with two episodes of enhanced terrestrial weathering indicated by an increased abundance of 13 C-enriched moretanes relative to hopanes and an elevated abundance of black carbon fragments. Key marine events previously reported for the PTB, including photic zone euxinia, faunal mass extinction, and cyanobacterial expansion, also occur as two episodes, coinciding with both of the progressive shifts to negative δ 13 C values and enhanced weathering. The temporal sequence of the duplicable events suggests that the biotic crisis was a consequence of prolonged and episodic changes in the marine and continental systems, and argues against an extraterrestrial impact as the main cause.