Department of Geosciences, University of Padova, Via G. Gradenigo 6, 35131, Padova, Italy.
IGG-CNR (Istituto Di Geoscienze E Georisorse), Padova, Firenze, Italy.
Sci Rep. 2024 Jul 6;14(1):15574. doi: 10.1038/s41598-024-66343-z.
The latest Triassic was characterised by protracted biotic extinctions concluding in the End-Triassic Extinction (~ 200 Ma) and a global carbon cycle perturbation. The onset of declining diversity is closely related to reducing conditions that spread globally from upper Sevatian (uppermost Norian) to across the Norian-Rhaetian boundary, likely triggered by unusually high volcanic activity. We correlate significant organic carbon cycle perturbations to an increase of CO in the ocean-atmosphere system, likely outgassed by the Angayucham igneous province, the onset of which is indicated by the initiation of a rapid decline in Sr/Sr and Os/Os seawater values. A possible causal mechanism involves elevated CO levels causing global warming and accelerating chemical weathering, which increased nutrient discharge to the oceans and greatly increased biological productivity. Higher export production and oxidation of organic matter led to a global O decrease in marine water across the Norian/Rhaetian boundary (NRB). Biotic consequences of dysoxia/anoxia include worldwide extinctions in some fossil groups, such as bivalves, ammonoids, conodonts, radiolarians.
最新的三叠纪以漫长的生物灭绝为特征，最终导致了三叠纪末期灭绝（约 2 亿年前）和全球碳循环扰动。多样性的减少与全球范围内从塞瓦特阶上部（最上部诺利阶）到诺利阶-瑞替阶边界的减少条件密切相关，这可能是由异常高的火山活动引发的。我们将显著的有机碳循环扰动与海洋-大气系统中 CO 的增加相关联，这可能是由 Angayucham 火成省释放的，该火成省的开始标志着 Sr/Sr 和 Os/Os 海水值的快速下降。一种可能的因果机制涉及到升高的 CO 水平导致全球变暖，并加速了化学风化，这增加了营养物质向海洋的排放，并大大增加了生物生产力。较高的输出生产力和有机物的氧化导致了整个海洋的全球 O 在诺利阶-瑞替阶边界（NRB）处下降。缺氧/缺氧的生物后果包括一些化石群的世界性灭绝，如双壳类、菊石类、牙形石类、放射虫类。
