Abstract The western limb of the Hellenic Arc defines the boundary of a large intracontinental active extensional domain covering the Aegean and the southwestern part of the Balkan peninsula. Along this boundary a transition from collision in the north to subduction in the south is associated with post-Miocene clockwise rotations of ∼ 50 ∘ . We present a new GPS velocity field that, with new permanent station velocities in Albania, Bulgaria, Kosovo, Montenegro, and Northern Macedonia, provides insights into previously unresolved aspects on the large-scale dynamics of continental lithosphere and on the relation between long and short-term kinematics. In particular we address (1) the kinematic description of the collision/subduction transition, (2) the relation between long-term finite rotations with geodetically-measured instantaneous rotations, (3) the forces maintaining and resisting the deformation of the extensional domain and (4) the extent of its northern boundary. We use the analogy of rigid elongate inclusions in the velocity field to predict the senses and approximate rates of rotation of crustal blocks in the deforming continental region. Across the collision/subduction transition zone a large rotational pattern in the velocity field is found whose spatial pattern and sense of rotation is compatible with the observed paleomagnetic rotations through the occurrence of fault-bounded block rotations. Geodetic observations show that clockwise vertical axis rotation of the western limb of the Hellenic margin is active today, with distribution and rates that are essentially the same as that defined by the paleomagnetic data for the last 5 Ma. The maximum rates of the rotational component of the velocity field is found along the wide arrangement of fault-bounded blocks in central Greece that accomodate the NE-SW dextral shear transferred from the northern Aegan trough. The northern limit of the rotating margin defines a hinge (Scutari-Pec transverse zone) that has remained stationary throughout the Middle Miocene (relative to the upper plate of the collision/subduction system) with important implications for the distribution of strength of the western margin of the Hellenic Arc. The distribution and style of deformation along the western boundary of the extensional domain is controlled by the relation between gravitational forces, driving the flow of crustal material towards the low-lying adjacent regions sea floor, and heterogeneous resistive forces along the collision/subduction boundary.

中文翻译：

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来自连续 GPS 测量的巴尔干西南部活跃地壳变形和旋转

摘要 希腊弧的西翼界定了一个覆盖爱琴海和巴尔干半岛西南部的大型大陆内活动伸展域的边界。沿着这条边界，从北部的碰撞到南部的俯冲的转变与中新世后顺时针旋转 ∼ 50 ∘ 相关。我们提出了一个新的 GPS 速度场，它在阿尔巴尼亚、保加利亚、科索沃、黑山和马其顿北部有新的永久站速度，提供了对以前未解决的大陆岩石圈大规模动力学和长短之间关系的见解-术语运动学。特别是我们解决了（1）碰撞/俯冲转变的运动学描述，（2）长期有限旋转与大地测量瞬时旋转之间的关系，(3) 维持和抵抗伸展域变形的力和 (4) 其北边界的范围。我们使用速度场中刚性细长包裹体的类比来预测变形大陆区域地壳块的旋转方向和近似速率。穿过碰撞/俯冲过渡带，发现了速度场中的大旋转模式，其空间模式和旋转方向与通过发生断层边界块旋转所观察到的古地磁旋转相一致。大地观测表明，今天希腊边缘西翼的顺时针垂直轴旋转很活跃，其分布和速率与过去 5 Ma 的古地磁数据所定义的基本相同。速度场的旋转分量的最大速率是沿着希腊中部断层边界块的广泛排列发现的，这些块容纳了从北爱根海槽转移的 NE-SW 右旋剪切。旋转边缘的北限定义了一个铰链（Scutari-Pec 横向带），该铰链在整个中中新世（相对于碰撞/俯冲系统的上板块）一直保持静止，对西边缘的强度分布具有重要意义希腊弧。沿伸展域西边界的变形分布和形式受重力关系控制，驱动地壳物质向邻近低洼地区海底流动，