Try a little experiment for us. Take a block of ice and a quarter. Now heat the quarter. Once it is cherry red, go ahead and put it on top of the ice block. Once it cools off, being caferul not to spill any of the melted ice, refreeze the block.
An "ice core" sample taken from outside the melt zone would show the original age of the ice. Only the melted portion burying the object would have a different "age". Mostly entrained gas composition and dust/pollen counts are used to deliniated random climatological changes from seaonal/annual ones.
Also, a dark object set on ice will heat at a different rate than the surrounding highly reflective ice. Anyone who has left an fish house on a frozen lake can attest to this phenomena.
But that's OK. Go shake your spear at the new moom to make it come back.