Abstract The Pialli Level in the Umbria-Marche Basin (central Italy) correlates with the lowermost part of the positive carbon isotopic excursion characterizing the late Albian–early Cenomanian Oceanic Anoxic Event 1d (OAE 1d). High-resolution litho-, bio- and chemostratigraphic data from the Monte Petrano and Le Brecce sections allow for a bed-by-bed comparison of the two successions, and discriminate local from basin-scale signals. We present new X-ray fluorescence, ICP-MS and TOC data for both the limestones and the Pialli Level shales integrated with available carbonate carbon isotopes and nannofossil temperature and nutrient indices. Data indicate a homogenous background sedimentation dominated by pelagic carbonates, biogenic silica with little contribution by clays. The limited variation in lithogenic elements points to an essentially homogeneous detrital source area with limited fluvial terrigenous input. Higher Mn concentrations coupled with low enrichments in redox-sensitive elements, such as U, Fe, S, Re, Mo, Ag, suggest that the Pialli Level shales represent temporary suboxia without reaching anoxia. Furthermore, P, authigenic Ba, Cd and Ni enrichments, together with nannofossil nutrient index indicate generally low primary productivity conditions along the entire succession, with only minor increases for some of the black-to-dark grey shales of the Pialli Level. The nannofossil temperature index highlights a warm climate during the OAE 1d, with the warmest conditions experienced during the deposition of the Pialli Level shales. During the late Albian, the warm and humid climate was interrupted by brief episodes of relatively warmer and less saline surface waters ensuring slower rates of bottom water renewal and producing temporary suboxic conditions. Such paleoceanographic dynamics would be the continuation of episodic warmer and humid pulses characterizing the late Albian interval in the Umbria-Marche Basin. As such, the Pialli Level can be considered the result of a last episode closing a cycle before the establishment of a steadier climate during the early Cenomanian.

中文翻译：

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大洋缺氧事件 1d (OAE 1d) 的主要和微量元素表征：来自意大利中部翁布里亚-马尔凯盆地的洞察

摘要 翁布里亚-马尔凯盆地（意大利中部）的 Pialli 水平与表征晚阿尔比安-早塞诺曼阶大洋缺氧事件 1d (OAE 1d) 的碳同位素正偏移的最低部分相关。来自 Monte Petrano 和 Le Brecce 剖面的高分辨率岩石、生物和化学地层数据允许对两个系列进行逐层比较，并区分局部和盆地尺度的信号。我们提供了石灰岩和 Pialli 级页岩的新 X 射线荧光、ICP-MS 和 TOC 数据，并结合了可用的碳酸盐碳同位素和纳米化石温度和营养指数。数据表明均质背景沉积主要由远洋碳酸盐、生物二氧化硅为主，粘土几乎没有贡献。岩性元素的有限变化表明具有有限河流陆源输入的基本均质碎屑源区。较高的 Mn 浓度加上对氧化还原敏感的元素（如 U、Fe、S、Re、Mo、Ag）的低富集表明 Pialli 层页岩代表了暂时的缺氧，而没有达到缺氧。此外，P、自生 Ba、Cd 和 Ni 的富集以及纳米化石营养指数表明整个序列的初级生产力条件普遍较低，而 Pialli 层的一些黑色至深灰色页岩仅略有增加。纳米化石温度指数突出了 OAE 1d 期间的温暖气候，在 Pialli 级页岩沉积期间经历了最温暖的条件。在阿尔比安晚期，温暖潮湿的气候被短暂的相对温暖和较少盐分的地表水中断，确保底水更新速度较慢并产生暂时的缺氧条件。这种古海洋动力学将是表征翁布里亚-马尔凯盆地晚阿尔比斯期的间歇性温暖和潮湿脉冲的延续。因此，Pialli 水平可以被认为是在 Cenomanian 早期建立更稳定的气候之前结束一个循环的最后一个事件的结果。