Abstract Organic geochemistry and palynology reveal major organofacies changes in the marginal marine Polish Basin during the early Toarcian linked to changes in environmental conditions. Increasing water salinity and enhanced biomass contributions from phytoplankton, adopted to brackish conditions, attest to periodic marine ingressions into the paralic, hyposaline Polish Basin. Marine ingressions occurred upon reoccurring sea level rises concomitant with i) the Pliensbachian-Toarcian boundary carbon isotope excursion (Pl-Toa-CIE) and ii) the stepped Toarcian carbon isotope excursion (Toa-CIE), the latter marking the Toarcian Oceanic Anoxic Event (Toa-OAE). Strata with marine influences indicate an intermittent connection of the Polish Basin with the Tethys and attest to a close correlation between regional shoreline progradation and evolution of global climate and sea-level. Organic geochemistry indicated the link between sea level fluctuations and the Toa-CIEs, although in some areas of the Polish Basin the sea level rise was balanced by massively increased sediment delivery, caused by enhanced hydrological cycling that lead to intensified weathering and erosion in the hinterland. Enhanced hydrological cycling further led to the remobilization of organic matter of pre-Toarcian age. This points to erosion of older organic-rich rocks containing significant abundances of marine and terrestrial organic matter that was partly oxidized and re-deposited along with autochthonous Toarcian organic matter. Provenance areas identified point to two main sources, most likely Carboniferous terrestrial/paralic and Ordovician/Silurian marine sediments. Fossil organic matter should be considered as additional source in Toarcian carbon cycling, particularly in times of enhanced hydrological cycling, erosion and weathering. Remobilization of sedimentary fossil carbon has not been hitherto considered as a carbon source during the Toa-OAE.

中文翻译：

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Toarcian 气候和碳循环扰动——它对海平面变化的影响，化石有机物质的动员和氧化增强

摘要 有机地球化学和孢粉学揭示了早期 Toarcian 边缘海洋波兰盆地的主要有机相变化与环境条件的变化有关。海水盐度增加和浮游植物对生物量的贡献增加，适应咸水条件，证明海洋定期进入近海、低盐度波兰盆地。海洋入侵发生在海平面再次上升时，同时伴随 i) Pliensbachian-Toarcian 边界碳同位素偏移 (Pl-Toa-CIE) 和 ii) 阶梯式 Toarcian 碳同位素偏移 (Toa-CIE)，后者标志着 Toarcian 海洋缺氧事件(Toa-OAE)。受海洋影响的地层表明波兰盆地与特提斯河间断连接，并证明区域海岸线进积与全球气候和海平面的演变之间存在密切相关性。有机地球化学表明海平面波动与 Toa-CIE 之间存在联系，尽管在波兰盆地的某些地区，海平面上升被大量增加的沉积物输送所平衡，这是由于水文循环增强导致腹地风化和侵蚀加剧. 增强的水文循环进一步导致了托阿尔时代前有机物的再活化。这表明较老的富含有机质岩石受到侵蚀，其中含有大量海洋和陆地有机质，这些有机质被部分氧化并与本土 Toarcian 有机质一起重新沉积。确定的来源区域指向两个主要来源，最有可能是石炭纪陆地/近海沉积物和奥陶纪/志留纪海洋沉积物。化石有机质应被视为 Toarcian 碳循环的额外来源，特别是在水文循环、侵蚀和风化增强的时期。在 Toa-OAE 期间，沉积化石碳的再动员迄今尚未被视为碳源。