Dynamical influences from thermal‐chemical instabilities at the core‐mantle boundary

Two‐dimensional, time‐dependent calculations show that the thermal and flow structures can be influenced by the lower‐mantle thermal‐chemical instabilities. The style of the core‐mantle boundary (CMB) deformation in thermal‐chemical convection is different from that obtained in thermal convection. The amplitude of CMB hills is reduced greatly from the depth‐dependence of thermal expansivity, found in recent high‐pressure experiments.