ABSTRACT The Proterozoic Longshan Formation in the Yanliao Aulacogen (North China Craton, NCC) represents a coastal siliciclastic succession. Its geologic age is debated (early Neoproterozoic vs. late Mesoproterozoic), which impacts the understanding of NCC basin evolution within the context of supercontinent cyclicity (Columbia to Rodinia). This study focuses on the Longshan Formation in the Xingcheng area of western Liaoning, incorporating regional stratigraphic correlation and paleogeographic analysis across the entire basin. Integration of sedimentology, stratigraphy, detrital zircon U–Pb geochronology, Hf isotopes and geochemistry clarifies the contact relationships, provenance and chronostratigraphic implications of this formation. Results show: (1) at the Shangchangmao section in Xingcheng, the Longshan Formation lies parallel unconformably on a chert breccia layer, indicating a regional hiatus; (2) detrital zircon spectra show prominent ~2.5 and ~1.85 Ga peaks. Hf isotopes reveal contrasting crustal growth mechanisms: juvenile mantle‐dominated at ~2.5 Ga and ancient crustal reworking at ~1.85 Ga; (3) Geochemical data indicate provenance primarily from the Archean Shanhaiguan Paleo‐land and late Paleoproterozoic felsic rocks; (4) regional correlation and paleogeographic reconstruction reveal a provenance paradox: the absence of ~1.38 Ga zircons in the Longshan Formation, despite their occurrence as volcanic tuffs in the underlying Xiamaling Formation. We resolve this by proposing a novel ‘burial‐dominated’ model, in which the Xiamaling Formation and its coeval tuffs remained buried in subsiding depocenters and were thus unavailable as sedimentary sources during the deposition of the Longshan Formation. Combined with the newly reported 1.32 Ga diabase sill ages that intrude the Longshan and Jing'eryu formations (providing an upper depositional limit), this model helps constrain the chronostratigraphic framework. Synthesizing sedimentological, provenance and regional stratigraphic data with this direct dating evidence, we accept the viewpoint that the Longshan Formation was deposited during the late Mesoproterozoic (post‐ ~1.38 Ga and pre‐ ~1.32 Ga). These conclusions provide new constraints on late Mesoproterozoic basin evolution and necessitate a re‐evaluation of the North China Craton's paleogeographic position within supercontinent cycles.
Yao et al. (Mon,) studied this question.