& nbsp; & nbsp; & nbsp; The chemical composition of the deep Earth is the core research content of mantle geochemistry. Previous studies have identified EM1 enriched mantle endmembers through the study of oceanic island basalt (such as Pitcairn Island, Tristan Gough Islands, etc.), which are characterized by extremely low 206Pb/204Pb and 143Nd/144Nd ratios. However, due to the high overall melting degree of mantle plumes and the thin thickness of the oceanic lithosphere, the EM1 component characteristics of oceanic island basalt are easily diluted during magma formation, and traditional geochemical methods are difficult to identify, and their genesis has always been controversial. The Cenozoic potassium basalts in the northwest side of the Songliao Basin in northeastern China have extreme radiogenic isotope composition characteristics (Figure 1) and are considered as continental equivalent components of EM1 type oceanic island basalts. Moreover, the thickness of the continental lithosphere is large, and the mantle melting degree of continental basalt is relatively low, which is more conducive to preserving the information of EM1 enriched end components. Barium (Ba) is a large ion lithophilic element that is highly incompatible during partial melting in the mantle. Previous studies have shown that Ba isotopes undergo significant fractionation in low-temperature environments and fluid interactions, while their fractionation is limited in high-temperature processes, making them a new tool for tracing the subduction and recycling of crustal materials< img src=" https://geology.nwu.edu.cn/uploads/20250221/c369bb48abf6b24d6ccc15b712dc7373.jpg " alt="" />

Paper information: Cheng, Y.S., Liu, J.Q.*, Chen, L.H., Chen, K.Y., Zhao, J., Wang, X.J., Krmicek, L., Zeng, G., Zhang, H.F. 2025. Barium isotope fingerprint for recycled ancient sediment in the source of EM1-type continental basalts. Geophysical Research Letters. 52, e2024GL111960. https://doi.org/10.1029/2024GL111960 

Article link: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024GL111960