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A series of tectonic activities induced by the subduction of the Palaeo‐Asian Ocean (PAO) in the Palaeozoic have been recorded in the North China Craton (NCC). Sedimentary strata provide some precious records to reconstruct the basin evolution in the NCC. In this study, we carried out detrital zircon LA‐ICP‐MS U–Pb dating, sandstone modal analysis, bulk‐rock major, and trace elemental measurements for the Sunjiagou and Liujiagou formations in the eastern Ordos Basin to trace the material source. The results show that the sedimentary rocks were mostly sourced from active continental margins. The detrital zircon ages of the Sunjiagou and Liujiagou formations spread from >3,000 to 250 Ma with peaks of main age populations at 2,508, 1,890, 430, and 270 Ma. Based on the age comparison and the southward palaeocurrents, we consider that the source material of these sedimentary rocks comes from the northern margin of the NCC. This in turn indicates that the amalgamation of the PAO and the NCC should have finished at least by the end of the Late Permian. [ABSTRACT FROM AUTHOR]

Typical ophiolitic rock assemblages such as siliciclastic rocks, basalts and gabbros, together with the subduction-related intermediate-acidic intrusive rocks, are newly discovered in the Tongjiang-Fuyuan area of the Heilongjiang Provence, NE China. To determine the formation age and genesis of the mafic rocks (basalts and gabbros) and intermediate-acidic intrusive rocks (granodiorites) in the area, as well as their geodynamic settings, the whole-rock geochemical analysis and zircon LA-ICP-MS U-Pb dating were carried out. Zircon U-Pb results suggest that the granodiorites are 93–95 Ma and gabbro is 95 Ma, respectively. Geochemical results show that the gabbros and basalts exhibit characteristics of ocean island basalt (OIB) affinity and are typically related to having originated from mantle plumes. While the granodiorites show the nature of the island-arc magmatic rocks and may originate from the lower crust. Based on the coeval igneous rock associations and regional tectonic evolution, we conclude that the late Cretaceous magmatic rocks in the Tongjiang-Fuyuan area are the product of continuous subduction of the Palaeo-Pacific plate and reflect the subduction rollback process of the Palaeo-Pacific plate. [ABSTRACT FROM AUTHOR]