The Euphrates-Tigris-Karun river system: Provenance, recycling and dispersal of quartz-poor foreland-basin sediments in arid climate
The Euphrates-Tigris-Karun river system: Provenance, recycling and dispersal of quartz-poor foreland-basin sediments in arid climate
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DOI：
10.1016/j.earscirev.2016.09.009
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发表时间：
2016-11
影响因子：
12.1
通讯作者：
E. Garzanti;A. Al‐Juboury;Yousef Zoleikhaei;P. Vermeesch;Jaafar Jotheri;D. B. Akkoca;Ahmed K. Obaid;M. Allen;S. Andó;M. Limonta;M. Padoan;A. Resentini;M. Rittner;G. Vezzoli
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文献类型：
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作者：
E. Garzanti;A. Al‐Juboury;Yousef Zoleikhaei;P. Vermeesch;Jaafar Jotheri;D. B. Akkoca;Ahmed K. Obaid;M. Allen;S. Andó;M. Limonta;M. Padoan;A. Resentini;M. Rittner;G. Vezzoli
我们对现代幼发拉底河-底格里斯河-卡伦河水系和人类摇篮之一的美索不达米亚前陆盆地进行了详细的沉积物源研究。我们丰富的岩相学和重矿物数据集，结合砂地球化学和碎屑锆石U-Pb年龄谱，突出了这个大的源-汇沉积路由系统的几个特点，并扩大了通常假设为造山环境的典范的组合物谱。经典的静态岩石学模型与升级的动态岩石学模型的比较增强了物源分析的能力，并使我们能够推导出更精确的参考概念模型，并验证该方法的局限性。来自Anatolia-Zagros造山带的砂包含丰富的由碳酸盐岩、硅质岩、泥岩、弧火山岩侵蚀而成的岩屑颗粒，仰冲蛇绿岩和蛇绿混杂岩代表造山带暴露的浅层结构水平，石英、钾长石和云母相对缺乏。这种石英贫乏的岩相学特征，表征了整个安纳托利亚-伊朗高原未切割的复合构造域，与喜马拉雅山等更高、侵蚀更快的碰撞造山带所脱落的沙子明显不同。该地区的干旱气候使化学性质不稳定的颗粒得以保存，包括碳酸盐岩石碎片和当地甚至石膏，并降低了河流系统的运输能力，这些河流系统将大部分负荷倾倒在阿拉伯/波斯湾碳酸盐变构工厂上游的美索不达米亚沼泽地。来自Anatolia-Zagros造山带的贫石英沉积物与来自阿拉伯沿着前陆盆地西侧的富石英再生砂混合，并沿沿着海湾海岸一直追踪到距离幼发拉底河源头4000公里的Rub' al-Khali沙海。
We present a detailed sediment-provenance study on the modern Euphrates-Tigris-Karun fluvial system and Mesopotamian foreland basin, one of the cradles of humanity. Our rich petrographic and heavy-mineral dataset, integrated by sand geochemistry and U–Pb age spectra of detrital zircons, highlights the several peculiarities of this large source-to-sink sediment-routing system and widens the spectrum of compositions generally assumed as paradigmatic for orogenic settings. Comparison of classical static versus upgraded dynamic petrologic models enhances the power of provenance analysis, and allows us to derive a more refined conceptual model of reference and to verify the limitations of the approach.Sand derived from the Anatolia-Zagros orogen contains abundant lithic grains eroded from carbonates, cherts, mudrocks, arc volcanics, obducted ophiolites and ophiolitic mélanges representing the exposed shallow structural level of the orogen, with relative scarcity of quartz, K-feldspar and mica. This quartz-poor petrographic signature, characterizing the undissected composite tectonic domain of the entire Anatolia-Iranian plateau, is markedly distinct from that of sand shed by more elevated and faster-eroding collision orogens such as the Himalaya. Arid climate in the region allows preservation of chemically unstable grains including carbonate rock fragments and locally even gypsum, and reduces transport capacity of fluvial systems, which dump most of their load in Mesopotamian marshlands upstream of the Arabian/Persian Gulf allochemical carbonate factory. Quartz-poor sediment from the Anatolia-Zagros orogen mixes with quartz-rich recycled sands from Arabia along the western side of the foreland basin, and is traced all along the Gulf shores as far as the Rub' al-Khali sand sea up to 4000 km from Euphrates headwaters.