[PIF]

One gets the same effect with an oblique meteoric impacter made of iron hitting at high rate of speed. The impacter essentially drags a vacuum behind it at the same temperature as space causing the flash frozen effect, while the impact itself sends out high speed particles which gouge the tusks.

Just an alternate explanation not a challenge

[amorphous]

IIRC, one of the theories is that larger impacters did create bubble vacuums which allowed lighter particles of cosmic origin to reach the surface.

The book listed above goes into great detail about what may have occurred.