The Kopet Dagh Mountains in NE Iran result from Cenozoic tectonic inversion of Triassic and Jurassic rifts that formed along the southern margin of the Eurasian continental plate. The Kopet Dagh defines an arcuate orogen leading to the suggestion that oroclinal bending took place during its formation. We performed a paleomagnetic study including seven sampling sites of Paleocene formations around the Kalat syncline in the East Kopet Dagh to test whether this part of the mountain belt experienced vertical-axis rotation. Paleomagnetic measurements and a reversals test indicate that parts of the collected samples may have been partially remagnetized. Overall paleomagnetic directions of all sample sites show a mean declination of 12.5°, which is the expected direction for stable Europe in the Paleocene and therefore negates any rotation related to regional tectonic events. Directions calculated only from reversely polarized paleomagnetic data, however, suggest clockwise vertical-axis rotations up to 21° since the Paleocene. Numerical modelling of a viscous multi-layer folding mimicking the Kalat syncline stratigraphy suggests that local deviations in overprinted site-mean directions and orientation of the maximum axes of the AMS ellipsoid may be related to complex folding kinematics, acquired after regional vertical-axis rotation, where related viscous flow of relatively weak interlayer is represented by the sampled Paleocene formation.

中文翻译：

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根据古磁数据推论，伊朗东北部东科佩达格的垂直轴旋转是：眼眶弯曲还是复杂的局部折叠运动学？

伊朗东北部的Kopet Dagh山脉是由沿欧亚大陆板块南缘形成的三叠纪和侏罗纪裂谷的新生代构造反转形成的。Kopet Dagh定义了一个弧形造山带，这暗示了在其形成过程中发生了眼眶弯曲。我们进行了古磁研究，包括东Kopet Dagh的Kalat向斜周围七个古新世地层的采样点，以测试这部分山脉是否经历了垂直轴旋转。古磁测量和逆转测试表明，部分采集的样品可能已被部分磁化。所有样品位点的总体古磁方向显示平均偏角为12.5°，这是欧洲在古新世稳定的预期方向，因此消除了与区域构造事件有关的任何旋转。然而，仅根据反极化的古磁数据计算的方向表明，自古新世以来，顺时针垂直轴旋转最多可达21°。模仿Kalat向斜地层的粘性多层折叠的数值模型表明，叠印的站点平均方向和AMS椭球最大轴方向的局部偏差可能与区域垂直轴旋转后获得的复杂折叠运动学有关，相对较弱的中间层的相关粘性流由古新世形成的采样表示。建议自新世以来顺时针垂直轴旋转最多21°。模仿Kalat向斜地层的粘性多层折叠的数值模型表明，叠印的站点平均方向和AMS椭球最大轴方向的局部偏差可能与区域垂直轴旋转后获得的复杂折叠运动学有关，相对较弱的中间层的相关粘性流由古新世形成的采样表示。建议自新世以来顺时针垂直轴旋转最多21°。模仿Kalat向斜地层的粘性多层折叠的数值模型表明，叠印的站点平均方向和AMS椭球最大轴方向的局部偏差可能与区域垂直轴旋转后获得的复杂折叠运动学有关，相对较弱的中间层的相关粘性流由古新世形成的采样表示。