Syn‐Collisional Origin of Yidun Arc‐Like Magmas and Northern Provenance of Songpan‐Ganzi Turbidites (Eastern Tibet)

ABSTRACT The accurate identification of ancient magmatic arcs through igneous characteristics is crucial for reliable paleogeodynamic reconstructions. This study evaluates the widely accepted Yidun arc hypothesis in the eastern Tibetan Plateau. Upper Triassic (235–200 Ma) high‐K metaluminous, arc‐type rocks in the Zhongza terrane show crustal reworking based on Hf isotopes. Lower–Middle Triassic turbidites intruded by these igneous rocks share detrital modes and detrital‐zircon U–Pb ages with Songpan‐Ganzi turbidites, supported by southward paleocurrents, indicating a shared northern Kunlun‐Qinling source. Field evidence confirms that turbidites in both the Zhongza and Songpan‐Ganzi terranes predate the widespread Upper Triassic arc‐like igneous rocks in Zhongza. These rocks formed via syn‐collisional, not oceanic subduction, magmatism, challenging the arc model. This highlights the importance of detailed geological analysis before interpreting arc‐like magmatism and inferring subduction polarity in ancient orogens.