The Origin of the Low-Velocity Anomalies Beneath the Rootless Atlas Mountains: Insights Gained From Modeling of Anisotropy Developed by the Travel of Canary Plume

As the mantle plume rises from the deep mantle and reaches the base of a tectonic plate, it changes its traveling direction from vertical to horizontal. The horizontal spread of plume material is often radially asymmetric. An example is a plume found below the Canary Hotspot. Previous studies have suggested that the channeling of the Canary Plume toward the westernmost Mediterranean (Alboran Sea) and consequent lithospheric delamination may have contributed to the low-velocity anomalies found beneath the Moroccan Atlas Mountains. Regional upwelling and edge-driven convection have been proposed as other candidates to explain the origin of the low-velocity anomalies. In this study, we incorporated anisotropy as an a priori constraint in teleseismic P-wave travel-time tomography as mantle flow can develop seismic anisotropy. We inverted a new set of travel-time delays by removing the hypothetical anisotropy-imposed travel-time delays from the observations. Our improved results are more consistent with the hypothesis that the low-velocity anomalies come from the mantle material of the Canary Plume.