Killer Comet

This is another book in the ones about something that happens around 12,000 to 13,000 years ago that results in massive changes to human civilization as it was then. The book discusses megafauna (very large animals), the Clovis people and just what caused the Younger Dryas which resulted in lower temperatures, the extinction of virtually all mega fauna in North America and it's severe impact on the humans living here at that time.

The book takes the approach that whatever impact Earth at that time, which was probably a comet and its pieces, hit the thick glaciers of the time and sent numerous shards out which did further damage go the ground and sent up water which became ice crystals and in the end lowered the temperature which was what killed off the megafauna and damaged the Clovis population.

Some of the material in the book is rather complicated but it's message is clear. Human civilization was making progress when things went very, very wrong very quickly.