I'm thinking, did it get cold enough there. People were living there,
Topper Site. The Gulf Stream would have had to stop flowing for it to get that cold, no? Last I read about the Topper Site, they were talking in the 14k-16k year range.
The thing is that here in Fairbanks we live on permafrost. It doesn't have to get much below freezing for permafrost to start forming, it happens in New England and NY and PA every winter. The trick is that it has to be a short summer to turn into permanently frozen ground. That's not going to make it super cold necessarily. I haven't paid much attention to the Gulf Stream theorists since that would be local rather than global, it's just North Atlantic.