Campanian lacustrine organic-rich mudstones were deposited under a warm greenhouse climate in Egypt. In this study, integrated elemental geochemical analyses have been applied to discriminate the paleoweathering conditions, provenance, and tectonic setting of these mudstones. The studied samples are relatively enriched in Al, Ca, V, Sc, and Cr compared to Post-Archean Australian shales (PAAS). Their chondrite normalized REE patterns show enrichment in the light REE compared to heavy REE, with a negative Eu anomaly (Eu/Eu* = ∼0.77). The low values of Th/Sc (0.42), Zr/Sc (5.05), and Zr/Hf (36.3) for the studied samples indicate no input from recycled older sedimentary strata. The ratios of the compositional variability index (ICV = 0.76), K/Al (0.072), Al/Si (0.34), and K/Si (0.025) suppose that the mudstones are compositionally mature source rocks and originated in quiescent and low energy depositional environments. The average values of the chemical index of alteration (CIA = 82), chemical proxy of alteration (CPA = 94), and plagioclase index of alteration (PIA = 87) and ln(Al₂O₃/Na₂O = 3.6) for the studied mudstones imply moderate to intensive chemical weathering. Moreover, the provenance sensitive elemental proxies (e.g., La/Sc, Th/Sc, Th/Cr, Cr/Th) and multiple discrimination diagrams reveal that the mudstones could be derived from intermediate igneous parent rocks. The lacustrine organic-rich sediments were sourced from a Phanerozoic to Proterozoic arc setting based on various tectonic discrimination diagrams.

中文翻译：

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埃及南部特提斯边缘的Campanian Lacustrine有机富集泥岩的物源表征

坎帕尼亚湖有机质丰富的泥岩是在埃及温暖的温室气候下沉积的。在这项研究中，综合元素地球化学分析已被用于区分这些泥岩的古风化条件，物源和构造背景。与Archean后澳大利亚页岩（PAAS）相比，研究样品的Al，Ca，V，Sc和Cr含量相对较高。与重质稀土元素相比，他们的球粒陨石归一化稀土元素模式在轻质稀土元素中富集，负Eu异常（Eu / Eu * =〜0.77）。研究样品的Th / Sc（0.42），Zr / Sc（5.05）和Zr / Hf（36.3）较低，表明没有回收旧沉积层的输入。组成变异指数（ICV = 0.76），K / Al（0.072），Al / Si（0.34）和K / Si（0。025）假设泥岩是成分成熟的烃源岩，起源于静态和低能沉积环境。化学变化指数（CIA = 82），化学变化代理（CPA = 94）以及斜长酶变化指数（PIA = 87）和ln（Al₂ O ₃ / Na ₂ O = 3.6）表明所研究的泥岩具有中等至强烈的化学风化作用。此外，对物源敏感的元素代理（例如，La / Sc，Th / Sc，Th / Cr，Cr / Th）和多重判别图表明，泥岩可能来自中间火成岩母岩。湖相中富含有机物的沉积物是根据各种构造判别图从生代弧到元古代弧形成的。