地质学
碳酸盐
生物集群灭绝
海洋酸化
显生宙
火成岩大省
海水
海洋学
古生物学
碳循环
地球化学
岩浆作用
构造盆地
生态系统
生态学
人口
社会学
人口学
生物
构造学
冶金
材料科学
新生代
生物扩散
作者
Tamás Müller,Hana Jurikova,Marcus Gutjahr,Adam Tomášových,Ján Schlögl,Volker Liebetrau,Luís V. Duarte,Rastislav Milovský,Guillaume Suan,Emanuela Mattioli,Bernard Pittet,Anton Eisenhauer
出处
期刊:Geology
[Geological Society of America]
日期:2020-08-13
卷期号:48 (12): 1184-1188
被引量:64
摘要
Abstract The loss of carbonate production during the Toarcian Oceanic Anoxic Event (T-OAE, ca. 183 Ma) is hypothesized to have been at least partly triggered by ocean acidification linked to magmatism from the Karoo-Ferrar large igneous province (southern Africa and Antarctica). However, the dynamics of acidification have never been directly quantified across the T-OAE. Here, we present the first record of temporal evolution of seawater pH spanning the late Pliensbachian and early Toarcian from the Lusitanian Basin (Portugal) reconstructed on the basis of boron isotopic composition (δ11B) of brachiopod shells. δ11B declines by ∼1‰ across the Pliensbachian-Toarcian boundary (Pl-To) and attains the lowest values (∼12.5‰) just prior to and within the T-OAE, followed by fluctuations and a moderately increasing trend afterwards. The decline in δ11B coincides with decreasing bulk CaCO3 content, in parallel with the two-phase decline in carbonate production observed at global scales and with changes in pCO2 derived from stomatal indices. Seawater pH had declined significantly already prior to the T-OAE, probably due to the repeated emissions of volcanogenic CO2. During the earliest phase of the T-OAE, pH increased for a short period, likely due to intensified continental weathering and organic carbon burial, resulting in atmospheric CO2 drawdown. Subsequently, pH dropped again, reaching the minimum in the middle of the T-OAE. The early Toarcian marine extinction and carbonate collapse were thus driven, in part, by ocean acidification, similar to other Phanerozoic events caused by major CO2 emissions and warming.
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