Liu Qian, Lü Ziqiang, Lei Jianshe
College of Mining, Liaoning Technical University, Fuxin, China.
Key Laboratory of Crustal Dynamics, National Institute of Natural Hazards, Ministry of Emergency Management of China, Beijing, China.
Sci Rep. 2024 Sep 27;14(1):22388. doi: 10.1038/s41598-024-73008-4.
The central and southern segments of the Tanlu fault zone, located in the collision boundary between the Yangtze Plate and the North China Craton, underwent complex tectonic deformation associated with the Pacific Plate subduction. The crustal thickness and Vp/Vs ratio are important parameters for comprehending tectonic evolution and geodynamic processes. By integrating a newly dense seismic array, our results based on P-wave receiver function analyses reveal the crust thickness varies significantly across the Tanlu fault zone. The Yangtze Plate is characterized by a thinner crust, contrasting a thicker crust imaged in the North China Craton, indicating the Tanlu fault zone is a prominent structural block boundary. The Vp/Vs ratio within the Tanlu fault zone is visibly higher than its surroundings, probably correlating with abundant fluids activity along the fault zone, as a result of the subduction of the Pacific Plate. Additionally, we observe a gradually deepening Moho discontinuity beneath the Sulu orogenic belt with a low-angle dip, presenting direct seismic evidence for supporting the ancient Yangtze Plate underthrusting beneath the Sulu orogenic belt.
郯庐断裂带的中南部位于扬子板块与华北克拉通的碰撞边界，经历了与太平洋板块俯冲相关的复杂构造变形。地壳厚度和Vp/Vs比值是理解构造演化和地球动力学过程的重要参数。通过整合一个新的密集地震台阵，我们基于P波接收函数分析的结果表明，郯庐断裂带地壳厚度变化显著。扬子板块地壳较薄，与华北克拉通成像的较厚地壳形成对比，表明郯庐断裂带是一个显著的构造块体边界。郯庐断裂带内的Vp/Vs比值明显高于其周边地区，这可能与太平洋板块俯冲导致沿断裂带丰富的流体活动有关。此外，我们观察到苏鲁造山带下莫霍面不连续面以低角度倾斜逐渐加深，为支持古代扬子板块俯冲到苏鲁造山带下提供了直接的地震证据。
