Abstract

At a late stage of its accretion, the Earth experienced high-energy planetary impacts. Following each collision, the metal core of the impactor sank as millimetric drops into a molten silicate magma ocean. The efficiency of chemical equilibration between these silicates and the metal core controlled the composition of the Earth controlled the initial temperature and composition of rocky planets, and hence the emergence of plate tectonics, the time when a solid inner core started to grow, or the driving of an early dynamo in the Earth’s core by exsolution of light elements.

In this talk I will present different experiments focusing on the interaction of settling particle clouds with their surrounding through entrainment, mixing and chemical reactions. I will first present experiments on inert clouds settling in a quiescent fluid. Then, I will discuss the implications of planetary rotation on the efficiency of chemical transfers inside particle clouds, largely disregarded despite the strong rotation rate of the proto-Earth that has been suggested by impact simulations.