There has been little to say from Earth and Planetary Science Letters…until now. Volume 648 (15 December 2024) includes:
Nimmo, F. Kleine, T. Morbidelli, A. et al. Mechanisms and timing of carbonaceous chondrite delivery to the Earth Article 119112 .2024.119112
The issue of Earth’s composition and accretion continues, and not just because we can’t directly sample the core (or even the lower mantle). Of all the meteorites, the enstatites most closely resemble the Earth’s isotopes, so Earth had to form from some amount of these meteorites… but not all, because the composition match is still imperfect. (Also, it’s pretty baffling to imagine the other kinds of meteorites had no contribution. None at all. What, was there some force field around early Earth or something?) The question remains: what else accreted to form the Earth?
Most hypotheses involve some ‘late veneer’- a top layer of Earth contaminated with lesser meteorites besides enstatites. A prime suspect is carbonaceous chondrite meteorites, since these are water-rich. Infall of C-chondrites (even just a percent or two of Earth’s mass) could explain our water, yet the bulk planet would still be enstatite-like. Nimmo et al. continue this subfield. Their results are broadly in line with previous authors: a minority of carbonaceous chondrites, falling onto a young but mostly-formed Earth, explains a lot.