Foreland fold-and-thrust belts (FTBs) are shaped by the coupled influence of surface processes (e.g., erosion, sedimentation) and deep geological processes (e.g., plate rheology, flexure and kinematics) across various timescales. These processes record multiple phases of orogenic evolution and are crucial for understanding the interplay between mountain building and the sedimentary basin filling. In this paper, we conducted an integrated study including magnetostratigraphy of exposed strata, detailed field investigations and interpretations of subsurface seismic profiles in the northern Kuqa Depression. This study aims to elucidate the tectonic uplift of the Tian Shan by examining salt-related structures. The present findings reveal that diapirism in the study area commenced in the early Eocene and continued at least into the late Miocene. Notably, the Tuzimaza diapir has been significantly squeezed due to regional contraction since ∼5.3 Ma. The exposed growth strata were primarily compressional, rather than halokinetic, suggesting the lateral expansion of the Tuzimaza anticline since the latest Miocene (∼5.3 Ma). This expansion was a response to the far-field effects of the Indian-Eurasian collision. We propose that the local activation of the Tian Shan likely initiated in the early Oligocene (∼34 Ma), with three subsequent episodes of deformation occurring ∼24 Ma, ∼10 Ma and ∼ 5.3 Ma. The earlier episodes can be attributed to basement uplift in the northern Kuqa Depression, whereas the later episode starting at ∼5.3 Ma reflects more intensive deformation across the entire foreland, indicative of the steady outward growth of the Tian Shan. Collectively, all these tectonic events have contributed to the formation of the modern Tian Shan.

中文翻译：

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西北库车坳陷北部年代学、构造与盐构造：对天山新生代隆升和前陆变形的影响


前陆褶皱和逆冲带 （FTB） 是由不同时间尺度上的表面过程（如侵蚀、沉积）和深部地质过程（如板流变学、弯曲和运动学）的耦合影响形成的。这些过程记录了造山运动的多个阶段，对于理解造山和沉积盆地填充之间的相互作用至关重要。在本文中，我们进行了一项综合研究，包括裸露地层的磁地层学、详细的实地调查和对库车洼地北部地下地震剖面的解释。本研究旨在通过研究与盐相关的结构来阐明天山的构造隆起。目前的研究结果表明，研究区域的底辟作用始于始新世早期，并至少持续到中新世晚期。值得注意的是，自∼5.3 马以来，由于区域收缩，Tuzimaza diapir 受到显着挤压。暴露的生长层主要是压缩的，而不是盐动力学的，这表明自最近的中新世（∼5.3 马）以来，Tuzimaza 背斜发生了横向扩展。这种扩张是对印度-欧亚碰撞的远场效应的回应。我们认为天山的局部激活可能始于渐新世早期（∼34 马），随后的三次变形发生在∼24 马、∼10 马和∼ 5.3 马。早期的事件可归因于北部库车坳陷的基底隆起，而较晚的事件从 ∼5.3 马 开始，反映了整个前陆更强烈的变形，表明天山稳定地向外增长。总的来说，所有这些构造事件都促成了现代天山的形成。