Mantle transition zone-derived EM1 component beneath NE China: Geochemical evidence from Cenozoic potassic basalts

- Potassic basalts in NE China sample an extreme EM1 endmember composition.
- Light Mg isotopic compositions suggest recycled crustal materials in the source.
- Long-term (∼2.2 Ga) isolation of recycled sediments generated low radiogenic Pb.
- Extracting carbonate melt elevated the residue's K/U and Ba/Th in transition zone.