Evolution history of the northeastern North China Craton: Implications for the magma sources of Changbaishan and Longgang volcanoes

To better understand the magma sources of Changbaishan and Longgang volcanoes in northeastern China, we investigated the metasomatism and melting history of the northeastern North China Craton (NCC). Our study includes whole-rock major and trace elements, platinum group element (PGE), and ReOs isotopic analyses of peridotite xenoliths entrained in Cenozoic volcanic rocks from the Changbaishan and Longgang volcanic fields. The peridotites are predominantly lherzolites with a small proportion of harzburgite, showing variable ${\mathrm{Al}}_2{O}_3$ contents (0.41–3.77 wt%). The more depleted samples $({\mathrm{Al}}_2{O}_3$ < 2 wt% & CaO < 2 wt%) yield a Re-depleted model age (T_RD) of approximately 1.80 Ga, consistent with other parts of the NCC. The peridotites exhibit increasing PGE patterns, with pronounced enrichment of Pd. The Pd enrichment in the peridotites is linked to subduction-derived materials, indicating that Pd was likely enriched through rock-melt reactions during metasomatism. Based on the tectonic setting, we propose that following the cratonization of the northeastern NCC, the lithospheric mantle remained stable and refractory for a long period until metasomatism caused by silicate melts released during ancient subductions. Additionally, these xenoliths show significant depletion in Re, Cu, and S, suggesting that after refertilization, the lithospheric mantle underwent recent low-degree partial melting. Therefore, we suggest that the magma sources for the Changbaishan and Longgang volcanic fields comprise a mixture of EM I (derived from the mantle transition zone), DMM (asthenospheric mantle), and minor EM II (lithospheric mantle).