Mantle plumes are readily identified beneath oceanic plates but are more difficult to recognize beneath continents. Whether this apparent scarcity reflects a true difference in plume distribution or observational limitations remains debated. Here we convert geomagnetic depth sounding data in the North China Craton to an electrical conductivity model that reveals a vertically continuous, high-conductivity anomaly through the mantle transition zone beneath the Ordos block. The inferred conductivity structure is consistent with an ∼400 K temperature excess. Combination with global seismic tomography indicates that the anomaly is potentially consistent with a lower-mantle upwelling that may align with deeper low-velocity structures that extend toward the margins of large low-shear-velocity provinces. Although our data do not uniquely require a classical whole-mantle plume, the vertically continuous geometry, inferred thermal structure, and regional geological context are collectively consistent with a plume-like upwelling beneath the North China Craton, which we tentatively term the Ordos mantle plume. The results suggest that continentally confined mantle upwellings may be more common than currently recognized and highlight the utility of electrical conductivity imaging for detecting deep thermal anomalies beneath stable cratonic lithosphere.
Guo et al. (Mon,) studied this question.