Provenance and metamorphic records of forearc sediments from the Heilongjiang Complex, NE China: Implications for subduction erosion associated with the Mudanjiang Ocean

Subduction erosion is widely thought to play a significant role in crustal recycling at modern convergent plate margins. However, identifying subduction fossil accretionary margins difficult due multiple episodes of tectonic superimposition and an absence direct geophysical evidence. By assessing provenance metamorphic records this study, we are the first document record Late Triassic Middle Jurassic meta-sedimentary rocks from Luobei Heilongjiang Complex, NE China. Most detrital zircons four samples have typical core-rim textures. Approximately 90% zircon cores yielded Phanerozoic ages with εHf(t) values +12.8 −17.6. Geochronological isotopic comparisons indicate that eastern Songnen Block were deposited forearc basin. The youngest span 229 176 Ma, while obtained rims range 209 185 Ma. Combined 186−165 Ma phengite 40Ar-39Ar rocks, suggests their protoliths during Triassic−Middle Jurassic. Mineral inclusions define peak blueschist-facies metamorphism pressure-temperature conditions 0.9−1.0 GPa 359−365 °C; indicates sediment overriding was abraded into channel underwent high-pressure metamorphism. Metamorphic (209−165 Ma) suggest period occurred slab subduction. These results reveal rapid progression early sedimentation (229−165 westward Mudanjiang Ocean.