Gary also sent this link at www.dailymail.co.uk/sciencetech/article-5144169/Earth-bombarded-small-pl… … (see also https://phys.org/print431591593.html ). Collisions 'after' the formation of the Moon 'remodelled' early Earth – all by using modeling processes (see Naturegeoscience at www nature.com/articles/doi.10.1038/s41561-017-0022-3 ). Basically, they have used computer simulation fo show the Earth could have been transformed by small planet sized asteroids after the collision that created the Moon. It would seem the theory the Moon was created following a giant collision with a planet sized object has been found wanting. Something does not fit the narrative. Either that or they are determined to get onboard the idea collisions with the Earth were the catalyst for the production of gold, silver, and platinum – and a big collision does not fit the bill'
However, the model assumes that all the sideraphile elements delivered by the asteroids were retained in the Mantle. Is this a flaw?
Interestingly, an article in the Science magazine (24th November 2017) describes a project, conceived in the 1990s but coming to fruition following the recent furore over gravitational waves emitted by a neutron star. The big news event was that such explosions created gold – which got the BBC drooling. The Science story also features gold, or rather the outside chance that gold may once day be created in laboratories.