Black lines show the temperature versus depth (taken at 4.5 Ga after CAIs) for varying accretion durations. Blue lines indicate the dehydration temperature of hydrated species. The steps in the temperature profiles result from the variation of the porosity and, thus, of the thermal conductivity with depth (see Fig. 5). While the internal temperature does not allow for magmatic activity of dry silicates today, existence of liquid water in the deep layers is still possible. For CIa the melting point of water is crossed at the depths of 80 km for t_ac = 2 Ma, 25 km for t_ac = 3 Ma, and 18 km for longer accretion durations. For CIb the respective depth varies between 32 km for t_ac = 2 Ma and 5 km for all t_ac ≥ 3 Ma. The higher temperatures in the shallower depths for a later accretion are due to the insulating properties of the porous layer.