This brings us to Mercury and the Pre-cambrian Earth and the full sequence of an Earth’s life-cycle as outlined in ‘The Visible Earths’. See 'Mercury' and 'Full Sequence'.

By the time the ecosphere is sufficiently clear so that the development of Earths is not threatened, the disk of gas and dust swirling around the star has been reduced to an outer-lying belt of more rubble-like debris. I believe this belt can be seen in this solar system in the form of the asteroid belt that lies mostly between Mars and Jupiter.

For the rest of this sequence see the ‘Asteroids’ section in ‘The Visible Earths’. ( this is where accretion is applied in this model, as the main process in the transformation from rock planet to gas giant, rather than as the primary source of generating the core and rock sphere in the beginning )