They also found evidence of the supernova explosion’s initial shockwave: 34,000-year-old mammoth tusks that are peppered with tiny impact craters apparently produced by iron-rich grains traveling at an estimated 10,000 kilometers per second. These grains may have been emitted from a supernova that exploded roughly 7,000 years earlier and about 250 light years from Earth.
https://www2.lbl.gov/Science-Articles/Archive/NSD-mammoth-extinction.html
Mammoths lived on Wrangell Island in the Arctic Ocean up until 4000 years ago.
How do micro grains of iron traveling a bazillion miles per hour survive re-entry into the Earth’s atmosphere?
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