Abstract The Iranian Plateau lies in the middle of the Neotethys tectonic domain; to the east it connects with the Tibetan Plateau, and to the west with the Anatolian Plateau and the Alpine orogenic belts. In the Cenozoic it underwent land/sea changes and tectonic uplift in response to the Arabia-Asia plate collision. One of the most prominent geological consequences of the collision was the disappearance of an epicontinental sea in Central Iran, which was a northeastern branch of the Neotethys seaway in the Oligocene-early Miocene. The timing of the final seawater retreat from Central Iran and its forcing mechanism are important for understanding the effects of Arabia-Asia plate collision as well as global eustatic sea-level changes. In this paper we present new magnetostratigraphy, U Pb ages of one tuffaceous bed, and stable isotopic records of carbonates. The results of this multidisciplinary study indicate that a shallow open sea in the Qom back-arc basin ended at 17 Ma, but the final seawater retreat from a restricted marine environment was at 16.8 Ma. The final regression was just before the Middle Miocene Optimum, implying that it was not related to a climatic factor, but driven by the Arabia-Asia plate collision. Moreover, the δ18O record of fine-grained lacustrine carbonates indicates an isotopic shift towards more positive isotopes after 13 Ma, suggesting an enhanced aridification in Central Iran. This climatic deterioration was a response to reduced transport of moisture by westerlies from a retreating Neotethys Sea driven by a global eustatic sea-level drop in response to the East Antarctica ice-sheet expansion after the middle Miocene Optimum.

中文翻译：

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中新世晚期新特提斯最后一次海水从伊朗中部撤退响应阿拉伯-亚洲碰撞的时间和强迫机制

摘要 伊朗高原位于新特提斯构造域的中部；东接青藏高原，西接安纳托利亚高原和高山造山带。在新生代，它经历了海陆变化和构造隆升，以响应阿拉伯-亚洲板块的碰撞。这次碰撞最突出的地质后果之一是伊朗中部的陆上海消失，该海是渐新世-早中新世新特提斯海道的东北支流。海水从伊朗中部最终撤退的时间及其强迫机制对于理解阿拉伯-亚洲板块碰撞的影响以及全球海平面变化很重要。在本文中，我们提出了新的磁地层学，一个凝灰质层的 U Pb 年龄，和碳酸盐的稳定同位素记录。这项多学科研究的结果表明，库姆弧后盆地的浅海在 17 Ma 结束，但最终海水从受限制的海洋环境中退缩的时间为 16.8 Ma。最后一次回归正好在中中新世最佳期之前，这意味着它与气候因素无关，而是由阿拉伯-亚洲板块碰撞驱动。此外，细粒湖相碳酸盐的 δ18O 记录表明在 13 Ma 之后同位素向更正的同位素移动，表明伊朗中部的干旱化增强。这种气候恶化是对西风从新特提斯海撤退的水分输送减少的反应，这是由于在中中新世最佳期之后南极洲东部冰盖扩张导致全球海平面下降所致。