Abstract During the Late Cretaceous, the dissolved silicon (DSi) concentration in the marine, pelagic environment of the epicontinental European Basin was controlled by the oceanic influx of DSi-enriched water. The inflow of oceanic water masses caused parts of the shelf basin that were influenced by them to reach DSi concentrations sufficient for opal-CT formation, leading to the abundant growth of siliceous sponges and the formation of carbonate–siliceous rocks (opoka). In the part of the basin, which was shielded from such oceanic influence, the DSi concentration was depleted (below the level necessary for quartz crystallisation) and pure carbonate sedimentation (chalk) occurred. In this study, the petrography, mineralogy, and microtextures of siliceous nodules (flints and cherts), which occur as abundant horizons within Campanian deposits of the European Basin, revealed events during which the DSi concentration was significantly elevated in both parts of the basin, leading to the crystallisation of silica polymorphs in the form of flint and chert nodules. The formation of siliceous nodule horizons was related to spatial and temporal fluctuations in the Campanian Si cycle triggered by large-scale hydrothermal and volcanic activity associated with Late Cretaceous the rearrangement of major plate boundaries in the Atlantic and Tethys Oceans. During such processes, a vast amount of DSi would have been released into the seawater and transported to the European Basin via oceanic inflow. The DSi-enriched seawater concentration in this shelf basin did not increase biosiliceous productivity, but instead triggered the abiotic precipitation of siliceous nodules during early diagenesis. The proposed model of an abiotic (volcano/hydrothermal) control for the formation of these nodules agrees with the existing literature on quartz precipitation hypothesis and counter to the widely discussed maturation hypothesis. Moreover, this proposed model suggests that, despite the gradual decline in seawater DSi concentrations throughout Earth's history, disturbances to the global geodynamic system caused by major plate boundary rearrangements governed the fluctuations of DSi concentration in the Cretaceous and periodically allowed for the formation of siliceous nodules. This study is the most exhaustive to-date, comparing to datasets from all previous petrographic, mineralogical and microtextural research and comprises 67 horizons of siliceous nodules form various parts of the Campanian European Basin.

中文翻译：

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晚白垩世硅循环的演化反映在硅质结核（燧石和燧石）的形成中

摘要 在晚白垩世期间，欧洲大陆表陆盆地海洋、远洋环境中的溶解硅 (DSi) 浓度受到富含 DSi 的水的海洋流入控制。海洋水团的流入导致受它们影响的部分陆架盆地达到足以形成蛋白石-CT 的 DSi 浓度，导致硅质海绵的大量生长和碳酸盐-硅质岩 (opoka) 的形成。在受海洋影响的盆地部分，DSi 浓度已耗尽（低于石英结晶所需的水平）并且发生纯碳酸盐沉积（白垩）。在这项研究中，硅质结核（燧石和燧石）的岩石学、矿物学和微观结构，在欧洲盆地坎帕尼亚沉积物中作为丰富的层位出现，揭示了在盆地两个部分的 DSi 浓度显着升高的事件，导致以燧石和燧石结核形式结晶的二氧化硅多晶型物。硅质结核层位的形成与坎帕阶硅旋回的时空波动有关，这是由与晚白垩世大西洋和特提斯洋主要板块边界重新排列相关的大规模热液和火山活动引发的。在这些过程中，大量 DSi 会被释放到海水中，并通过海洋流入输送到欧洲盆地。该陆架盆地中富含 DSi 的海水浓度并未提高生物硅质生产力，而是在早期成岩作用期间引发了硅质结核的非生物沉淀。这些结核形成的非生物（火山/热液）控制模型与现有关于石英沉淀假说的文献一致，并与广泛讨论的成熟假说相反。此外，该模型表明，尽管在整个地球历史上海水 DSi 浓度逐渐下降，但主要板块边界重排对全球地球动力学系统的干扰控制了白垩纪 DSi 浓度的波动，并定期导致硅质结核的形成. 与之前所有岩相学的数据集相比，这项研究是迄今为止最详尽的，