Continental Hotspots Tracks From an Analysis of GOCE Gravity Gradients Data.

This study aims to detect residual thermal anomalies along the path of a hotspot beneath the continental lithosphere using gradiometry data. We calculate perturbations in gravity vectors and gradients by employing a simple thermal anomaly model. The results highlight that the horizontal components of Bouguer gravity gradients, sensitive to source structure and elongation, exhibit substantial magnitudes, exceeding current detection levels. To improve signals from sources of different sizes and orientations, we apply a filtering approach involving wavelet transforms and rotated local frames. We also assess the impact of lateral crustal variations on the gravity field by introducing random density anomalies and a seismic crustal model, testing the method's ability to distinguish between these anomalies and thermal sources. Using Gravity field and steady‐state Ocean Circulation Explorer satellite data, we generated scale‐orientation diagrams aiming to identify signals aligned with the direction of plate movement and with a spatial scale of a few hundred kilometers (scale of the plumes). Maps of filtered Bouguer gravity gradients aligned with hotspot trajectories are generated for all continental hot plumes, with the position and the age of the intraplate volcanism to support the interpretation. While we do not show a clear signal in regions that are too tectonically complex or with lateral variations in the crust or at the lithospheric boundary correlated with the hotspot trace, we found observed signals with expected sign and amplitude over Hoggar, Tibesti, Darfour and Cameroon tracks in Africa and over Iceland and Jan Mayen in Greenland. However, determining corresponding mass source depths remains a complex task. Plain Language Summary: This study aims to detect residual heat patterns from hotspots beneath the continental lithosphere by analyzing gravity changes using gradiometry data. The results reveal significant gravity variations, particularly horizontally, suggesting the presence of heat sources beyond current detection capabilities. To improve signal detection for varied heat source sizes, we employ a filtering approach with wavelet transforms and rotated frames. The impact of crustal gravity variations is also considered, testing the ability to distinguish between different anomalies. Utilizing Gravity field and steady‐state Ocean Circulation Explorer satellite data, we create diagrams identifying signals linked to plate movement and heat source size, and we generate maps displaying filtered gravity gradients changes along hotspot paths on continents. While complex tectonic regions show no clear signal, expected signals are observed over specific tracks in Africa and Greenland. Determining the depth of corresponding mass sources remains a challenging aspect of the study. Key Points: We reconstruct hotspots trajectories on the continental lithosphere and we superimpose the position of the age of intraplate volcanismWe build maps of Bouguer gravity gradients filtered at the spatial scale of a few hundred kilometers and oriented along the trajectoriesWe show that gradiometry data have the potential to track hotspots in the continental lithosphere for tens of millions years [ABSTRACT FROM AUTHOR]