On the Relation Between Basal Erosion of the Lithosphere and Surface Heat Flux for Continental Plume Tracks.

While hotspot tracks beneath thin oceanic lithosphere are visible as volcanic island chains, the plume‐lithosphere interaction for thick continental or cratonic lithosphere often remains hidden due to the lack of volcanism. To identify plume tracks with missing volcanism, we characterize the amplitude and timing of surface heat flux anomalies following a plume‐lithosphere interaction using mantle convection models. Our numerical results confirm an analytical relationship in which surface heat flux increases with the extent of lithosphere thinning, which is primarily controlled by the viscosity structure of the lower lithosphere and the asthenosphere. We find that lithosphere thinning is greatest when the plate is above the plume conduit, while the maximum heat flux anomaly occurs about 40–140 Myr later. Therefore, younger continental and cratonic plume tracks can be identified by observed lithosphere thinning, and older tracks by an increased surface heat flux, even if they lack extrusive magmatism. Plain Language Summary: Extra heat is transmitted through Earth's tectonic plates above hot upwellings called plumes, and contributes to the heat budget of glaciated regions such as Greenland. A thin oceanic plate moving over such an upwelling typically yields a chain of age‐progressing volcanic islands such as Hawaii. However, such volcanism is often missing in continental regions such as Africa or Greenland, which have thicker plates. Nonetheless, the passage of the plate over the upwelling leaves a trace in the form of a reduced plate thickness and an increased amount of emitted heat even millions of years after the plume passage. In this study, we use numerical models of mantle convection to show that these two observations are directly linked to each other, with a larger heat flux anomaly observed for areas that have been thinned more extensively. Furthermore, we demonstrate that there is a significant time delay between the thinning, which happens during the passage of the upwelling, and the heat flux that is observed many millions of years later. As a consequence, past interactions of plates with plumes can influence today's heat output in continental regions. Key Points: We used numerical and analytical approaches to characterize heat flux anomalies following plume impingement on the lithosphereSurface heat flux anomalies follow an analytical relationship that predicts increasing heat flux with increasing basal lithospheric erosionLithosphere thinning is mostly controlled by viscosity structure, with a maximum surface heat flux anomaly following 40–140 Myr later [ABSTRACT FROM AUTHOR]