A Tilted Broad Plume Underneath the Greenland Cratonic Keels

Abstract To advance our comprehension of the complex geological history and mantle dynamics in the North Atlantic region, we employ all available broadband seismic data recorded in Greenland to reveal an abnormal mantle transition zone (MTZ) structure. Central and eastern Greenland exhibits depressed 410 and 660 km discontinuities (d410 and d660, respectively) bordering the MTZ, indicative of a substantial thermal anomaly associated with an underlying plume, surpassing the 1,800°C threshold for post‐garnet phase transitions at the d660. Variations in MTZ thickness across Greenland stem from differing temperature anomalies at the d410 and d660, possibly linked to a tilted plume within the MTZ. These findings corroborate geodynamic models, elucidating the interaction between post‐garnet phase transitions and upwelling plumes. The results shed light on the origin of the enigmatic Icelandic hotspot track and its influence on the thermal and lithospheric structures beneath Greenland.