Over the past few decades, Toarcian (Early Jurassic) black shale deposits of NW Europe have been extensively studied, and the possible global and regional mechanisms for their regional variation have been discussed. In this context, the black shales of the Northwest German Basin are still sparsely studied with regard to their palaeo-depositional history. This study aims to understand the connection between regional and global influences on the widespread Early Toarcian oceanic anoxic event by examining two wells covering the Upper Pliensbachian to Upper Toarcian sediments in the Northwestern German Basin. The core intervals were analysed using a multidisciplinary approach, including geochemistry, biostratigraphy and organic petrography. Marine palaeoenvironmental changes were reconstructed, and sediment sequences were stratigraphically classified to allow a supra-regional stratigraphic correlation. The results reveal complex interactions between sea level changes, climate warming, basin confinement, and Tethys–Arctic connectivity resulting in the Toarcian black shale deposition. Upper Pliensbachian sediments were deposited under terrigenous influence, shallow water depths, and predominantly oxic bottom water conditions. The deposition of black shale is characterized by algal organic material input and anoxic bottom water conditions. Strong correlations between water stratification, anoxia, and bioproductivity suggest that global warming and intensification of monsoonal rainfall, continental weathering, and increasing freshwater and nutrient inputs were the main factors controlling the formation of black shales. Prolonged deposition of OM-rich sediments in the NWGB may be related to intensified monsoonal precipitation in northern Europe and enhanced Tethys–Arctic connectivity at the serpentinum–bifrons transition.

Graphical Abstract

中文翻译：

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西欧下侏罗统（普林斯巴赫阶 - 托阿尔阶）海洋古环境：下萨克森盆地 Mainzholzen 和 Wickensen、Hils 向斜井的沉积学、地球化学和有机岩石学

在过去的几十年里，人们对欧洲西北部的托阿尔期（早侏罗世）黑色页岩矿床进行了广泛的研究，并讨论了其区域变化的可能的全球和区域机制。在这种背景下，德国西北部盆地黑色页岩的古沉积历史研究仍然很少。本研究旨在通过检查覆盖德国西北部盆地上普林斯巴阶至上托阿尔阶沉积物的两口井，了解区域和全球对广泛的早托阿尔阶海洋缺氧事件的影响之间的联系。使用多学科方法对岩心层段进行分析，包括地球化学、生物地层学和有机岩相学。重建了海洋古环境变化，并对沉积物序列进行了地层分类，以实现超区域地层关联。结果揭示了海平面变化、气候变暖、盆地限制以及特提斯-北极连通性之间复杂的相互作用，导致托阿尔期黑色页岩沉积。上普林斯巴阶沉积物是在陆源影响、浅水深度和主要含氧底水条件下沉积的。黑色页岩沉积的特点是藻类有机物质输入和缺氧底水条件。水层化、缺氧和生物生产力之间的强相关性表明，全球变暖和季风降雨的加剧、大陆风化以及淡水和养分输入的增加是控制黑色页岩形成的主要因素。NWGB 中富含 OM 沉积物的长期沉积可能与北欧季风降水增强以及蛇纹岩-双峰过渡处特提斯-北极连通性增强有关。

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