Oceanic red beds (ORBs) are present in Upper Cretaceous and Danian deep-marine deposits in the Basque–Cantabrian Basin of northern Spain. The presence and regularity of the succession of marl–limestone couplets is exceptional based on the macroscopic, microscopic and geochemical evidence collected. Five types of marl–limestone couplets are identified based on the colour, and a high maximum sedimentation rate (3.6 cm ka–1 ) is noted. The oxidizing activity of deep, cold-water masses is indicated by the oxygen isotope signal in the lower–upper Maastrichtian and Danian sections and the presence of the boreal inoceramid Spyridoceramus tegulatus. In theory, the variation in colour from grey to greenish-yellow, purple and pink up to red tones correlates with the Fe2+/(Fe2++Fe3+) ratio. It is interpreted as the possible palaeoenvironmental transit of particles that sediment out slowly in oxic environments when they circulate through cooler, oxidizing water masses. The colour is considered to be a depositional feature, and hematite, detected by X-ray diffraction, is the main staining agent, without discarding the possible redistribution of previous oxyhydroxides passing to hematite as a final product. The cell filling of the foraminifer shells does not incorporate appreciable amounts of Fe and Mg during diagenesis. Bacterial activity is detected using scanning electron microscopy images, both in the coccolith debris and in the detrital micas, although there is uncertainty as to its importance in the staining process.

中文翻译：

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海洋红层色素沉着的同沉积过程：来自巴斯克-坎塔布连盆地（西班牙北部）的证据

在西班牙北部巴斯克-坎塔布连盆地的上白垩统和大年深海沉积物中存在大洋红层 (ORB)。基于所收集的宏观、微观和地球化学证据，泥灰岩-石灰岩对联的连续存在和规律性是例外的。根据颜色识别出五种类型的泥灰-石灰石对联，最大沉降速率高（3.6 cm ka–1) 被注明。深冷水团的氧化活性由下-上马斯特里赫特和达尼安剖面中的氧同位素信号以及北方 inoceramid 的存在表明Spyridoceramus tegulatus。理论上，从灰色到绿黄色、紫色和粉红色到红色色调的颜色变化与 Fe2+/(铁2++铁3+） 比率。它被解释为当颗粒在较冷的氧化水团中循环时，在有氧环境中缓慢沉淀出来的颗粒可能在古环境中迁移。颜色被认为是一种沉积特征，通过 X 射线衍射检测到的赤铁矿是主要的染色剂，而不会丢弃先前作为最终产品传递到赤铁矿的羟基氧化物的可能重新分布。有孔虫壳的细胞填充在成岩过程中不包含可观量的 Fe 和 Mg。使用扫描电子显微镜图像检测细菌活动，无论是在球石碎片和碎屑云母中，但其在染色过程中的重要性尚不确定。