  The history of accretion and differentiation processes in the planetesimals
is provided by various groups of meteorites. Sampling different parent body
layers, they reveal the circumstances of the metal-silicate segregation and the
internal structures of the protoplanets. The ungrouped achondrite Erg Chech 002
(EC 002) added to the suite of samples from primitive igneous crusts. Here we
present models that utilize thermo-chronological data for EC 002 and fit the
accretion time and size of its parent body to these data. The U-corrected
Pb-Pb, Al-Mg, and Ar-Ar ages used imply a best-fit planetesimal with a radius
of 20-30 km that formed at 0.1 Ma after CAIs. Its interior melted early and
differentiated by 0.5 Ma, allowing core and mantle formation with a transient
lower mantle magma ocean, and a melt fraction of <25 % at the meteorite
layering depth. EC 002 formed from this melt at a depth of 0.8 km in a
partially differentiated region covered by an undifferentiated crust. By
simulating collisions with impactors of different sizes and velocities, we
analyzed the minimum ejection conditions of EC 002 from its original parent
body and the surface composition of the impact site. The magma ocean region
distinct from the layering depth of EC 002 implyes that it was not involved in
the EC 002 genesis. Our models estimate closure temperatures for the Al-Mg ages
as 1060 K to 1200 K. A fast parent body cooling attributes the late Ar-Ar age
to a local reheating by another, late impact.
