Highly siderophile elements in Earth’s mantle as a clock for the Moon-forming impact
Jacobson SA, Morbidelli A, Raymond SN, O’Brien DP, Walsh KJ and Rubie DC (2014)
(03 April 2014)
Using HSE abundance measurements13, 14, we determine a Moon-formation age of 95 ± 32 Myr after condensation. The possibility exists that some late projectiles were differentiated and left an incomplete HSE record in Earth’s mantle. Even in this case, various isotopic constraints strongly suggest that the late-accreted mass did not exceed 1 per cent of Earth’s mass, and so the HSE clock still robustly limits the timing of the Moon-forming event to significantly later than 40 Myr after condensation.