Abstract In this study, we analyse and interpret a new seismic reflection profile across the Xuefengshan Belt (XFSB), South China, to determine the deep structure of this belt and provide insights into collisional orogenic architecture. We identify a deep regional fault located beneath the XFSB, which cuts through the reflection Moho below the belt and is interpreted as representing the collisional boundary between the Yangtze and Cathaysia blocks along the southeastern margin of the belt. We identify structural evidence for collision between the two blocks, including two groups of layered narrow slip belts (∼30 km) in the middle crust, one distributed in the Yangtze Block and the other in the Cathaysia Block. A narrow velocity-gradient belt in the upper mantle at a depth of ∼90 km is revealed by numerous strong seismic reflectors, some of which are layered. The study provides important new information on the lithospheric structure of the South China Block at the interface between the Yangtze and Cathaysia blocks.

中文翻译：

---

华南雪峰山带岩石圈结构：来自地震反射剖面的证据

摘要 在这项研究中，我们分析和解释了华南雪峰山带 (XFSB) 的新地震反射剖面，以确定该带的深层结构并提供对碰撞造山构造的见解。我们确定了位于 XFSB 下方的深部区域断层，它穿过带下方的反射莫霍面，被解释为代表沿带东南边缘的扬子和华夏地块之间的碰撞边界。我们确定了两个地块碰撞的构造证据，包括中地壳的两组层状狭窄滑移带（~30 公里），一组分布在扬子地块，另一组分布在华夏地块。许多强地震反射层揭示了上地幔中约 90 公里深度的狭窄速度梯度带，其中一些是分层的。该研究为华南地块在扬子地块和华夏地块交界处的岩石圈结构提供了重要的新信息。