Accretion of Saturn's mid-sized moons during the viscous spreading of young massive rings: Solving the paradox of silicate-poor rings versus silicate-rich moons

► We model the accretion of moons from the spreading of massive rings (4× Rhea' mass). ► All Saturn's moons up to (and including) Rhea can be formed by this single process. ► Moons will end on their today's orbit if Saturn's dissipation is intense (Qsat < 2000). ► Silicate are expelled from the rings to the moons via migration (types 1 and 2). ► Heterogeneous accretion forms naturally differentiated satellites at the ring's edge.