Abstract The Ordos Basin is the largest cratonic basin in the North China Craton (NCC) with minimal intra-basin deformation in the Phanerozoic, making itself a good proxy to study the Precambrian evolution of the NCC. The distribution of the Precambrian strata and associated structural deformation in the Ordos Basin, however, remain an enigma due to the thick covering of the Phanerozoic strata. Herein, we depicted the residual thicknesses of the oldest sedimentary strata above the basement in the Ordos Basin, the late Paleoproterozoic to Mesoproterozoic Changcheng and Jixian systems, by combined forward and inverse modeling of the Bouguer Gravity Anomaly (BGA) data. The distribution of associated basement-involved faults was extracted by applying the signal-processing methods (e.g., the small sub-domain filtering and the total horizontal derivative) to the BGA data. The results were further calibrated by available geological constraints from limited borehole loggings, outcrops and seismic reflection data. They reveal an E- to NE-striking rift system with the development of plenty of syn-depositional normal faults and several uplifts and sags in the late Paleoproterozoic to Mesoproterozoic period in the Ordos Basin. The rift deposits reach ~8000 m in thickness in the southwestern Ordos Basin but thin toward north-northeast. The preexisting basement tectonics played an important role in the development of this rift system. Combined with regional tectonics, our findings imply that the late Paleoproterozoic to Mesoproterozoic extension in the Ordos Basin may not be related to the mantle plume centered in the Xiong’er Rift to the southeast, but instead likely results from the oceanic subduction beneath the southern margin of the NCC. This supports that the southern margin of the NCC may not connect with any other continental blocks in the reconstruction of the Paleoproterozoic Columbia Supercontinent.

中文翻译：

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鄂尔多斯盆地晚古元古代至中元古代裂谷系统及其构造意义：对布格重力异常的分析

摘要 鄂尔多斯盆地是华北克拉通（NCC）中最大的克拉通盆地，显生宙盆地内变形最小，是研究华北克拉通前寒武纪演化的良好代表。然而，由于显生宙地层的厚覆盖，鄂尔多斯盆地前寒武纪地层的分布和相关的构造变形仍然是一个谜。在此，我们通过布格重力异常（BGA）数据的正反演结合建模，描绘了鄂尔多斯盆地基底上方最古老沉积地层、晚古元古代至中元古代长城系和蓟县系的残余厚度。通过应用信号处理方法（例如，小子域过滤和总水平导数）到 BGA 数据。结果通过有限钻孔测井、露头和地震反射数据的可用地质约束进一步校准。它们揭示了鄂尔多斯盆地晚古元古代至中元古代大量发育同沉积正断层和多处隆起凹陷的东—北东向裂谷系。鄂尔多斯盆地西南部裂谷沉积厚度达 8 000 m，但向东北偏北方向变薄。先前存在的基底构造在该裂谷系统的发展中发挥了重要作用。结合区域构造，我们的研究结果表明，鄂尔多斯盆地晚古元古代至中元古代的伸展可能与以熊耳裂谷为中心的东南部地幔柱有关，而可能是华北克拉通南缘下方的大洋俯冲作用所致。这支持了在古元古代哥伦比亚超大陆的重建中，华北克拉通南缘可能不与任何其他大陆块相连。