Some subducted material appears to reach the lower mantle, while in other regions, this material is impeded from sinking further, possibly due to a phase transition from spinel to silicate perovskite and magnesiowustite, an endothermic reaction.
The movement of subducted material is influenced by a phase transition from spinel to silicate perovskite and magnesiowustite in some regions, potentially hindering its descent in other areas.