Intraplate Basalts in Eastern Continental China Record the Subduction History of the Pacific Plate

To assess whether intraplate magmatism in eastern continental China records the subduction history of the Pacific plate, we plotted elemental compositions of the volcanic rocks in this region since the Early Cretaceous as a function of age. These rocks show distinct compositional transitions at ∼110 and ∼50 Ma, coinciding with the cessation of paleo-Pacific plate subduction and initiation of present-day western Pacific plate subduction, respectively. The dehydration of subducted oceanic slab in the mantle transition zone (MTZ) (410–660 km) governs key parameters such as overlying lithospheric thickness, melt extraction depth, partial melting extent, and asthenospheric mantle enrichment, ultimately controlling the compositions of mantle-derived melts. Therefore, continental intraplate volcanism in regions with (present or past) subducted oceanic plates stagnant in the MTZ records the subduction history of adjacent oceanic plates.