title: Three-dimensional instabilities of mantle convection with multiple phase transitions.
abstract: The effects of multiple phase transitions on mantle convection are investigated by numerical simulations that are based on three-dimensional models. These simulations show that cold sheets of mantle material collide at junctions, merge, and form a strong downflow that is stopped temporarily by the transition zone. The accumulated cold material gives rise to a strong gravitational instability that causes the cold mass to sink rapidly into the lower mantle. This process promotes a massive exchange between the lower and upper mantles and triggers a global instability in the adjacent plume system. This mechanism may be cyclic in nature and may be linked to the generation of superplumes.
authors.forename: S
authors.initials: S
authors.lastname: Honda
authors.forename: D A
authors.initials: DA
authors.lastname: Yuen
authors.forename: S
authors.initials: S
authors.lastname: Balachandar
authors.forename: D
authors.initials: D
authors.lastname: Reuteler