Tectonic Evolution of the Northeastern Margin of North China Craton During Late Palaeozoic

The tectonic mélange belts along the northeastern margin of the North China Craton (NCC) provide critical insights into the closure of the Paleo‐Asian Ocean (PAO) and the formation and evolution of the Central Asian Orogenic Belt (CAOB). Due to the lack of early Late Palaeozoic geological records in this region, understanding the initiation and polarity of PAO subduction remained unclear. Recently identified Middle Devonian and Lower Carboniferous meta‐clastic rocks and Upper Devonian meta‐volcanic rocks from the “Xia'ertai” tectonic complex in the northeastern margin of the NCC have provided new evidence. Comprehensive geological surveys, mineralogical and petrographic studies, geochemistry, and zircon U–Pb isotopic dating were conducted. The Middle Devonian meta‐clastic rocks (muscovite two‐feldspar gneiss) exhibit high SiO 2 and Al 2 O 3 contents, notable REEs fractionation, and negative Eu anomalies. Zircon U–Pb dating reveals ages between 384 and 443 Ma. These rocks, with sandstone as the protolith and granitic rocks as their provenance, formed in a basin along the continental margin during the extensional stage after arc–continent collision. The Upper Devonian meta‐volcanic rocks (biotite plagioclase gneiss) belong to the high‐K calc‐alkaline series, are metaluminous to weakly peraluminous, and show a pronounced REEs fractionation and negative Eu anomalies. Zircon U–Pb dating gives a weighted average age of 381 Ma. These rocks are classified as highly differentiated I‐type magmatic rocks, originated from partial melting of the lower crust, and formed in an active continental margin environment. The Lower Carboniferous meta‐clastic rocks (two‐mica quartz schist) have high SiO 2 and Al 2 O 3 contents, distinct REE patterns, and negative Eu anomalies. Zircon U–Pb ages range from 324 to 370 Ma. These rocks, with sandstone as the protolith and felsic volcanic rocks as their sole provenance, formed in an active continental island arc environment. Integrating these findings with previous research, we propose a four‐stage tectonic evolution model for the northeastern margin of the NCC from the Early–Middle Devonian to Late Carboniferous: (1) Extensional phase following an arc–continent collision (Early‐Middle Devonian); (2) Formation of an active continental margin arc due to the intensified southward subduction (modern coordinate system) of the PAO plate (Late Devonian); (3) Continued southward subduction of the oceanic lithosphere (Early Carboniferous); (4) Development of fore‐arc and back‐arc basins (Late Carboniferous).