It is unlikely that the Earth's mantle — the layer beneath the crust and above the core — was completely homogeneous when it initially formed. Over time, cooling-induced convection as well as ...

Overall, Professors Sun and Tkalčić determine that mantle convection is the primary cause of Mars's unusual dichotomy, not giant impacts as the alternative hypothesis suggests. But their ...

evidence suggests it is the plates that drive the convection. Slab pull occurs where older, denser tectonic plates sink into the mantle at subduction zones. As these older sections of plates sink ...