“What is exciting in our paper is that we have for the first time narrowed down the region where a Younger Dryas impact did take place, even though we have not yet found its crater,” Prof Sharma said.

There is a known impact crater in Quebec – the 4-km-wide Corossal crater. However, based on mineralogical and geochemical studies, it is not the impact source for the material found in Pennsylvania and New Jersey.