The Taiyuan Formation, located on the northern margin of the Ordos Basin, has an important role in reconstructing tectonic paleogeography and evolutionary process due to its preservation of information about the tectonic evolution of the basin throughout the Late Paleozoic. The provenance, paleogeography, and tectonic activity traits of the Taiyuan Formation were examined using the sedimentary petrology and zircon chronology methods. The Alxa block is consistent with the dating results of the Taiyuan Formation in Shabatai, and the Daqing Shan is consistent with the results of the Taiyuan Formation in Xiachengwan and Adaohai. It is inferred that the provenance of the Taiyuan Formation in the western part of the northern margin of the basin is from the Alxa block, and the provenance in the eastern part is from the Daqing Shan when combined with the study of sandstone detrital components, and paleocurrent. In the late Paleozoic, the Siberian plate collided with the North China Craton, and the Taiyuan Formation was deposited in the northern margin of the Ordos Basin. However, on account of the different ages and types of basement rocks and the central paleo-uplift which has not completely disappeared, the Taiyuan Formation has obvious east-west zonation.

Abundant Early Cretaceous magmatism is conserved in the central and southern Great Xing’an Range (GXR) and has significant geodynamic implications for the study of the Late Mesozoic tectonic framework of northeast China. In this study, we provide new high-precision U–Pb zircon geochronology, whole-rock geochemistry, and zircon Hf isotopic data for representative intrusive rocks from the northern part of the Ulanhot area to illustrate the petrogenesis types and magma source of these rocks and evaluate the tectonic setting of the central-southern GXR. Laser ablation inductively coupled plasma–mass spectrometry (LA-ICP-MS) zircon U–Pb dating showed that magmatism in the Ulanhot area (monzonite porphyry: 128.07 ± 0.62 Ma, quartz monzonite porphyry: 127.47 ± 0.36, quartz porphyry: 124.85 ± 0.34, and granite porphyry: 124.15 ± 0.31 Ma) occurred during the Early Cretaceous. Geochemically, monzonite porphyry belongs to the metaluminous and alkaline series rocks and is characterized by high Al₂O₃ (average 17.74 wt.%) and TiO₂ (average 0.88 wt.%) and low Ni (average 4.63 ppm), Cr (average 6.69 ppm), Mg^# (average 31.11), Y (average 15.16 ppm), and Yb (average 1.62 ppm) content with enrichment in Ba, K, Pb, Sr, Zr, and Hf and depletion in Ti, Nb, and Ta. The granitic rocks (e.g., quartz monzonite porphyry, quartz porphyry, and granite porphyry) pertain to the category of high-K calc-alkaline rocks and are characterized by high SiO₂ content (>66 wt.%) and low MgO (average 0.69 wt.%), Mg^# (average 31.49 ppm), Ni (average 2.78 ppm), and Cr (average 8.10 ppm) content, showing an affinity to I-type granite accompanied by Nb, Ta, P, and Ti depletion and negative Eu anomalies (δEu = 0.57–0.96; average 0.82). The Hf isotopic data suggest that these rocks were the product of the partial melting of juvenile crustal rocks. Notably, fractionation crystallization plays a crucial role in the process of magma emplacement. Combining our study with published ones, we proposed that the Early Cretaceous intrusive rocks in the Ulanhot area were formed in an extensional tectonic background and compactly related to the subduction of the Paleo-Pacific Ocean plate.