Abstract Structural inversion of strike–slip faults in response to plate kinematic changes and interactions of large–scale basement blocks is a significant phenomenon in continental collision zones. In the Alborz Mountains, at the northern margin of the Iranian Plateau, Late Cenozoic kinematic of major fault systems changed in the late Pliocene from dextral to sinistral strike–slip. This kinematic change has been attributed to the clockwise rotation of the rigid South Caspian Block. However, the spatial extent and distribution of this kinematic change toward the south and into the Iranian Plateau is controversial. Here we present a detailed structural analysis of the West Saveh fault system located at the northwestern margin of the Iranian Plateau to unravel the regional distribution of this kinematic change. The West Saveh fault system is composed of the WNW–ESE trending Kushk–e Nosrat, Khalkhab, Saveh, and Nashveh faults. We identified several different sets of strike–slip related structures, which are classified into three categories based on their cross–cutting relationship and superimposition of kinematic indicators. We document dextral, dextral transpression and sinistral kinematics and their relative timing since Miocene time in the West Saveh fault system. Our structural analysis indicates recent slip sense inversion from dextral transpression to sinistral strike–slip, which possibly occurred in post Pliocene time. This kinematic change is regional and can be explained by the clockwise rotation of the South Caspian Block similarly to the kinematic change documented in the Alborz Mountains. We propose that the kinematic change due to South Caspian Block rotation is not restricted to the Alborz Mountains, but also affected the Iranian Plateau during post Pliocene time.

中文翻译：

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伊朗中部断层倒转：伊朗北部高原边缘后上新世陆内左侧横向运动学的证据

摘要 响应板块运动学变化和大尺度基底块体相互作用的走滑断层构造反转是大陆碰撞区的一个重要现象。在伊朗高原北缘的阿尔伯兹山脉，晚新生代主要断裂系统的运动学在上新世晚期由右向走滑转变为左向走滑。这种运动学变化归因于刚性南里海地块的顺时针旋转。然而，这种向南进入伊朗高原的运动学变化的空间范围和分布是有争议的。在这里，我们对位于伊朗高原西北边缘的 West Saveh 断层系统进行了详细的结构分析，以揭示这种运动学变化的区域分布。West Saveh 断层系统由 WNW-ESE 走向的 Kushk-e Nosrat、Khalkhab、Saveh 和 Nashveh 断层组成。我们确定了几组不同的走滑相关结构，根据它们的横切关系和运动学指标的叠加将其分为三类。我们记录了自西萨维断层系统中新世以来的右旋、右旋压榨和左旋运动学及其相对时间。我们的结构分析表明最近从右旋挤压到左旋走滑的滑移感反转，这可能发生在上新世之后。这种运动学变化是区域性的，可以通过南里海地块的顺时针旋转来解释，类似于 Alborz 山脉中记录的运动学变化。