Abstract The Talesh Mountains (NW Iran) witnessed a long deformation history from the Triassic Cimmerian orogeny to the ongoing Arabia-Eurasia collision. This protracted multi-stage deformation has generated a remarkably curved orogen with a puzzling kinematic and deformational history. In this study, we investigate the origin of the Talesh curvature through paleomagnetic analyses on rocks of Paleozoic, Mesozoic and Cenozoic age. Our results indicate that at least two major, large-scale, vertical-axis-rotations took place since the Late Cretaceous: 1) a pre-Eocene 73° ± 17° clockwise rotation and 2) post-Eocene differential rotations that formed the Z-shaped mountain belt within a crustal-scale shear zone. The latter involved an increasing amount of clockwise (CW) rotation from south (16°) to north (48°). The orocline formation likely started during the Oligocene where an approximately east-west oriented mountain belt was buckled by the Arabia-Eurasia collision, with Arabia acting as a rigid indenter and the South Caspian basin as a rigid backstop. We hypothesise that the NE-SW oriented Aras and Lahijan fault zones, inherited from transform faults related to the Mesozoic opening of the Caspian-Black Sea back-arc, accommodated the coupled orocline formation.

中文翻译：

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Talesh（伊朗西北部）的后始新世耦合oroclines：古地磁约束

摘要 塔莱什山脉（伊朗西北部）见证了从三叠纪辛梅里造山运动到正在进行的阿拉伯-欧亚大陆碰撞的漫长变形历史。这种长期的多阶段变形产生了一个明显弯曲的造山带，其运动学和变形历史令人费解。在这项研究中，我们通过对古生代、中生代和新生代岩石的古地磁分析来研究 Talesh 曲率的起源。我们的结果表明，自晚白垩世以来，至少发生了两次主要的、大规模的垂直轴旋转：1) 始新世前 73°±17° 顺时针旋转和 2) 始新世后差异旋转，形成了 Z地壳尺度剪切带内的形山带。后者涉及从南 (16°) 到北 (48°) 的顺时针 (CW) 旋转量增加。斜斜的形成很可能开始于渐新世，在那里，阿拉伯-欧亚大陆的碰撞使大约东西向的山带弯曲，阿拉伯作为刚性压头，南里海盆地作为刚性支撑。我们假设从与里海-黑海弧后中生代开口相关的转换断层继承的 NE-SW 取向的 Aras 和 Lahijan 断层带适应耦合的山坡地层。