The Cenomanian–Turonian Boundary Event (CTBE) as recorded in the northern margin of Africa: palaeoceanography of the Oceanic Anoxic Event (OAE-2), North-Central Tunisia

Samples spanning the Cenomanian–Turonian transition at Guern Halfaya Section of North-Central Tunisia were analysed for elemental and isotopic chemostratigraphic characterization of the OAE-2 global anoxic event. Comparison with other published sections of the same age was achieved. These geochemical analyses, which cover the local Bahloul Formation, add new insights into the palaeoceanographic evolution of the southern Tethyan margin during the Cenomanian–Turonian transition. The use of discrete redox-sensitive and primary productivity-sensitive trace element data coupled to isotopic and biostratigraphic events is shown as leading proxies for the determination of prevailing warming palaeoceanographic conditions, in terms of productivity and climate, during the OAE-2 in the northern margin of Africa. Such event is believed to have generated one among the most significant source rocks of the region.

针对突尼斯中北部盖恩半哈亚剖面（Guern Halfaya Section）中跨越森诺曼期-土仑期过渡界面（Cenomanian–Turonian transition）的样品开展分析，以表征全球大洋缺氧事件2（Oceanic Anoxic Event 2, OAE-2）的元素与同位素化学地层学特征。本研究同步完成了与同期其他已发表剖面的对比工作。上述覆盖当地巴胡鲁组（Bahloul Formation）的地球化学分析，为特提斯洋南缘在森诺曼期-土仑期过渡阶段的古海洋演化进程提供了全新认知。研究证实，离散氧化还原敏感型与初级生产力敏感型微量元素数据，结合同位素与生物地层事件数据，可作为非洲北缘在OAE-2事件期间，从生产力与气候维度判定当时主导性古海洋升温状况的核心代用指标。该缺氧事件被认为是该区域最为重要的烃源岩形成事件之一。