The Toarcian Oceanic Anoxic Event (T-OAE, ~183 Ma) represents a well-known episode of organic-rich deposition, which is accompanied by a substantial negative carbon-isotope excursion (CIE). Underpinning the relationships between the carbon-cycle perturbation, ocean anoxia, primary productivity feedbacks and the enrichment of sedimentary organic carbon remains a major challenge. Here, we present high-resolution geochemical, palynological and organofacies data from three lower Toarcian successions from the NW European shelf, spanning the T-OAE. Chronostratigraphic calibration of the successions is achieved through organic carbon isotope (δ¹³C) records. Iron-speciation and major and trace-element data indicate that bottom-waters were euxinic and intermittently anoxic-ferruginous prior to, throughout and beyond the CIE. In terms of organofacies and palynological composition, the CIE-interval is dominated by dense clusters of amorphous organic matter containing abundant small spherical prasinophyte cysts (Halosphaeropsis liassica). The peak CIE is bracketed by a major increase in abundance of prasinophycean vegetative cysts (Tasmanites and Pleurozonaria spp.). On the basis of their modern physiology, this suggests shoaling of the chemocline into the photic zone. The combined proxy data suggest a scenario in which anoxygenic photosynthetic productivity proliferated in nutrient-rich, anoxic to seasonally euxinic surface-waters of the stratified NW-European shelf during the CIE. A return to oxic-marine conditions is recorded by the recurrence of organic-walled dinoflagellate cysts in accordance with enhanced water column mixing post CIE. This is concurrent with a gradual termination of strongly stratified conditions across the NW-European shelf.

Toarcian海洋缺氧事件（T-OAE，〜183 Ma）代表着众所周知的富含有机物的沉积，伴随着大量的负碳同位素漂移（CIE）。碳循环扰动，海洋缺氧，初级生产力反馈和沉积有机碳富集之间的关系仍然是主要挑战。在这里，我们提供了来自欧洲西北大陆架的三个较低的Toarcian演替的高分辨率地球化学，孢粉学和有机相数据，横跨T-OAE。的继承的年代地层校准是通过有机碳同位素来实现（δ ¹³C）记录。铁形态以及主要和痕量元素数据表明，在CIE之前，整个过程以及以后，海底水都是富氧的和间歇性的缺氧铁质。就有机相和孢粉学组成而言，CIE间隔主要是由密集的无定形有机物质簇组成，这些簇含有大量球形的拟藻类植物囊肿（Halosphaeropsis liassica）。CIE的峰值被大量的藻类藻类营养囊肿（塔斯马尼亚人和侧耳菌属）所包围spp。）。根据它们的现代生理学，这表明将趋化环浅滩化至光化带。合并的代理数据表明了一种情景，即在CIE期间，分层的NW-欧洲陆架的营养丰富，缺氧至季节性富余的地表水中增产了产氧光合生产力。通过在CIE后根据增强的水柱混合，有机壁的鞭毛藻囊肿的复发记录了有氧海洋条件的恢复。与此同时，整个西北欧洲大陆架上的强分层条件也逐渐终止。