Abstract The Khondalite Belt is an important orogenic belt in the Western Block of the North China Craton that was formed by the collision of the Ordos and Yinshan blocks in the Paleoproterozoic. In the background to the Mesozoic multi-plate convergence, the Western Block lithosphere was activated along with magma and tectonic activity. Being an important collision zone, the Khondalite Belt is a key area where the modification and destruction of the Western Block can be studied. In this study, 440 sets of magnetotelluric array data were used to obtain a three-dimensional resistivity model of the study area. The resulting model revealed that the crust in the study area could be divided into three layers. The first layer exhibited an overall low-resistivity anomaly with some regional high-resistivity anomalies, while the second and third layers exhibited high- and low-resistivity anomalies, respectively. Furthermore, the model elucidated obvious boundaries between the Khondalite Belt and the Yinshan Block. The area controlled by the western and eastern Helanshan faults may be the western boundary of the Khondalite Belt. However, there was no obvious boundary to the south or east, as the bounding area exhibited low resistivity, possibly caused by a severely modified lithosphere. As a result of the characteristics of the magmatic rocks’ xenoliths, magnetic anomalies, and low S-wave velocities, low-resistivity anomalies developed in the lower crust and upper mantle, which were related to the partial melting. The scale of the partial melting did not cover the entire collision zone. Rather, it only covered the structural weak zone, especially the Jining area in the eastern Khondalite Belt. Therefore, the eastern section of the lithosphere was potentially modified by the Paleo-Pacific Plate subduction.

中文翻译：

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华北克拉通西部地块孔达岩带及邻区三维电性结构及深部动力学

摘要 孔达岩带是华北克拉通西部地块重要的造山带，由古元古代鄂尔多斯地块与银山地块碰撞形成。在中生代多板块辐合的背景下，西部地块岩石圈随着岩浆和构造活动而被激活。孔达岩带作为重要的碰撞带，是研究西地块改造破坏的重点区域。本次研究利用440组大地电磁阵列数据获得研究区三维电阻率模型。由此产生的模型表明，研究区的地壳可分为三层。第一层整体呈现低阻异常，部分区域存在高阻异常，而第二层和第三层分别表现出高电阻率和低电阻率异常。此外，该模型阐明了孔达岩带和银山地块之间的明显边界。贺兰山西部和东部断裂控制的区域可能是孔达岩带的西部边界。然而，南部或东部没有明显的边界，因为边界区域呈现出低电阻率，可能是由岩石圈严重改变造成的。由于岩浆岩的包体、磁异常和低横波速度等特点，在下地壳和上地幔中发育与部分熔融有关的低电阻率异常。部分熔化的规模没有覆盖整个碰撞区。相反，它只覆盖了结构薄弱区，尤其是孔达岩带东部的济宁地区。因此，岩石圈东段可能受到古太平洋板块俯冲的影响。