Abstract- Eastern Margin of Tunisia and the Pelagic Sea were affected by four magmatic events during the Cretaceous. During these events, the products are mainly interbedded basalts, numerous mafic sills and dykes, volcanic breccias and pyroclastic products. Petrography, mineralogy and geochemistry studies prove two lineages of basalts: basalts with tholeiitic affinity and alkali basalts. Electronic microprobe studies of clinopyroxene prove an anorogenic context of this magmatism. We used variable distribution of incompatible trace element ratios, such as Th/Ta, Th/Tb, or Th/Hf. These elements are characterized by distinct mantle composition source and different partial melting trends. These data suggest that the magma of tholeiitic affinity basalt is originated within the enriched mantle (EM1), moderate impoverishment in light rare-earth elements (LREE). The mantle source of alkali basalt is compositionally transitional between the high-U/Pb mantle (HIMU) and enriched mantle (EM2). The tectonic history of the area combined to the new mineralogical and geochemical investigations of subsurface cretaceous basalts will contribute significantly to place this magmatism in its Mediterranean context. Tectonic models are proposed to explain the geodynamic and the tecto-magmatic history of the studied area during Cretaceous.

中文翻译：

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突尼斯东部边缘和远洋海地下白垩纪玄武岩矿物学和微量元素变化：新数据和地球动力学意义

【摘要】：突尼斯东缘和远洋海在白垩纪受到四次岩浆事件的影响。在这些事件中，产物主要是互层玄武岩、大量基性基岩和岩脉、火山角砾岩和火山碎屑产物。岩石学、矿物学和地球化学研究证明了玄武岩的两个谱系：具有拉斑亲和性的玄武岩和碱性玄武岩。单斜辉石的电子微探针研究证明了这种岩浆作用的造山背景。我们使用了不相容微量元素比率的可变分布，例如 Th/Ta、Th/Tb 或 Th/Hf。这些元素具有不同的地幔成分来源和不同的部分熔融趋势。这些数据表明拉斑亲合玄武岩的岩浆起源于富集地幔（EM1），轻稀土元素 (LREE) 的中度贫化。碱性玄武岩的地幔来源在高U/Pb地幔（HIMU）和富集地幔（EM2）之间在成分上过渡。该地区的构造历史与地下白垩纪玄武岩的新矿物学和地球化学调查相结合，将大大有助于将这种岩浆作用置于地中海环境中。提出了构造模型来解释白垩纪研究区的地球动力学和构造岩浆历史。该地区的构造历史与地下白垩纪玄武岩的新矿物学和地球化学调查相结合，将大大有助于将这种岩浆作用置于地中海环境中。提出了构造模型来解释白垩纪研究区的地球动力学和构造岩浆历史。该地区的构造历史与地下白垩纪玄武岩的新矿物学和地球化学调查相结合，将大大有助于将这种岩浆作用置于地中海环境中。提出了构造模型来解释白垩纪研究区的地球动力学和构造岩浆历史。