The heterogeneity of continental mantle: A perspective from the Hannuoba basalts and mantle xenoliths

Understanding the heterogeneity of continental mantle is crucial for studying geological processes such as crustal component recycling and crust-mantle interaction. This study reviews the research of mantle-derived rocks (basalts, peridotites, pyroxenites) from different mantle depths beneath the Hannuoba region of the northern margin of the North China Craton, to investigate the continental mantle heterogeneity in the vertical direction. The study of Hannuoba basalts revealed the presence of recycled carbonated eclogites at the top of asthenosphere mantle and enriched ancient oceanic crust and sedimentary components at the bottom of lithosphere mantle beneath the Hannuoba region. Additionally, the peridotite and pyroxenite xenoliths carried by host basalts record multi-stage melt/fluid activities of different sources (altered oceanic crust, sedimentary carbonates, clastic sediments, delaminated lower continental crust, asthenosphere) and different compositions (silicate and carbonate). The addition of melt/fluid from enriched crustal materials significantly affected the homogeneity of sub-continental mantle beneath the Hannuoba region, and then sub-continental mantle displays chemical heterogeneity at the scale from micrometre to kilometre. The understanding of sub-continental mantle heterogeneity beneath the Hannuoba region provides an excellent window for studying crustal materials recycling