  Collision and disruption processes of proto-planetary bodies in the early
solar system are key to understanding the genesis of diverse types of main-belt
asteroids. Mesosiderites are stony-iron meteorites that formed by mixing of
howardite-eucrite-diogenite-like crust and molten core materials and provide
unique insights into the catastrophic break-up of differentiated asteroids.
However, the enigmatic formation process and the poorly constrained timing of
metal-silicate mixing complicate the assignment to potential parent bodies.
Here we report high-precision uranium-lead dating of mesosiderite zircons by
isotope dilution thermal ionization mass spectrometry, revealing initial crust
formation 4,558.5 +/- 2.1 million years ago and metal-silicate mixing at
4,525.39 +/- 0.85 million years. The two distinct ages coincide with the timing
of crust formation and a large-scale reheating event on the eucrite parent
body, likely the asteroid Vesta. This chronological coincidence corroborates
that Vesta is the parent body of mesosiderite silicates. Mesosiderite formation
on Vesta can be explained by a hit-and-run collision 4,525.4 million years ago
that caused the thick crust observed by NASA's Dawn mission and explains the
missing olivine in mesosiderites, howardite-eucrite-diogenite meteorites, and
vestoids.
