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

H. Genda, R. Brasser, S. J. Mojzsis
(Submitted on 22 Sep 2017)

Overabundances in highly siderophile elements (HSEs) of Earth’s mantle can be explained by conveyance from a singular, immense (3000 km in a diameter) “Late Veneer” impactor of chondritic composition, subsequent to lunar formation and terrestrial core-closure. Such rocky objects of approximately lunar mass (about 0.01 M_E) 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 (about 45degree), the impactor’s core elongates and thereafter disintegrates into a metallic hail of small particles (about 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 (

Comments:    Accepted for publication in Earth and Planetary Science Letters, 17 pages, 4 figures
Subjects:    Earth and Planetary Astrophysics (astro-ph.EP)
Cite as:    arXiv:1709.07554 [astro-ph.EP]  (or arXiv:1709.07554v1 [astro-ph.EP] for this version)
Submission history
From: Hidenori Genda
[v1] Fri, 22 Sep 2017 00:49:32 GMT (6031kb)
https://arxiv.org/abs/1709.07554