tp070.html

Accretion History of Terrestrial Planets There are two main thoughts I want you to take away from this:

If our models are right, the Earth is made up of material that formed in different regions.
- The planetary embryos probably differentiated at different times.
- Details depend on the mass of the disk and the orbits of Jupiter and Saturn.
During final assembly, the Earth accreted of both differentiated and undifferentiated material.

(O'Brien, Morbidelli, & Levison)
- The mass accreted after the last impact is roughly consistent with siderophile abundance in the Earth's mantle as discussed in Drake & Righter (2002).