[cs02rm0]

If an arrow shaft was found from about 1500 years ago, does that imply there probably wasn't ice there at the time? Or were people hunting on the ice then?

[mkl]

The latter. Anything under the glacier would be pulverised into dust (the glaciers even carve out their own valleys). These artefacts must have started up above the ice (on top or down a crack), so the people would have been hunting on the ice or maybe travelling across it.

[nudq]

I don't think we can simply assume that starting position matters to "pulverization" after 1500 years.

Mobility is more likely; the mobile object moves along with the ice, the stationary one gets pulverized.

[mkl]

I think even moving things that started on the ground would probably be crushed by the weight, since they would be at the bottom.

[ryanmercer]

Almost certainly icy areas, simply for the fact that the weight of the ice could easily crush and mangle any artefacts if the ice formed over them while they'd have much better survival chances the higher up in the ice layer they spent the bulk of their time in. Ötzi for example was travelling through a cold and icy region, it is what preserved him (although he's 3x as old).

Ice weighs 0.919 grams per cubic centimeter or 919 kilograms per cubic meter, for those of us more familiar with inches/feet that means a cubic foot of ice 57.4 pounds. That weight adds up quickly.