Details

Autor(en) / Beteiligte

• Genda, H.
• Brasser, R.
• Mojzsis, S.J.

Titel

The terrestrial late veneer from core disruption of a lunar-sized impactor

Ist Teil von

• Earth and planetary science letters, 2017-12, Vol.480, p.25-32

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2017

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• Overabundances in highly siderophile elements (HSEs) of Earth's mantle can be explained by conveyance from a singular, immense (D∼3000 km) “Late Veneer” impactor of chondritic composition, subsequent to lunar formation and terrestrial core-closure. Such rocky objects of approximately lunar mass (∼0.01 M⊕) ought to be differentiated, such that nearly all of their HSE payload is sequestered into iron cores. Here, we analyze the mechanical and chemical fate of the core of such a Late Veneer impactor, and trace how its HSEs are suspended – and thus pollute – the mantle. For the statistically most-likely oblique collision (∼45°), the impactor's core elongates and thereafter disintegrates into a metallic hail of small particles (∼10 m). Some strike the orbiting Moon as sesquinary impactors, but most re-accrete to Earth as secondaries with further fragmentation. We show that a single oblique impactor provides an adequate amount of HSEs to the primordial terrestrial silicate reservoirs via oxidation of (<m-sized) metal particles with a hydrous, pre-impact, early Hadean Earth. •Earth's late veneer is explicable via a single lunar-mass impactor after core formation.•Elongation, disruption and disintegration of cores occur in oblique collisions.•Oxidation of shattered cores suspends highly siderophile elements in the mantle.