  Hypervelocity impacts cause significant heating of planetary bodies. Such
events are recorded by a reset of 40Ar-36Ar ages and/or impact melts. Here, we
investigate the influence of friction and plastic deformation in
shock-generated comminuted rocks on the degree of impact heating using the
iSALE shock-physics code. We demonstrate that conversion from kinetic to
internal energy in the targets with strength occurs during pressure release,
and additional heating becomes significant for low-velocity impacts (<10 km/s).
This additional heat reduces the impact-velocity thresholds required to heat
the targets with the 0.1 projectile mass to temperatures for the onset of Ar
loss and melting from 8 and 10 km/s, respectively, for strengthless rocks to 2
and 6 km/s for typical rocks. Our results suggest that the impact conditions
required to produce the unique features caused by impact heating span a much
wider range than previously thought.
