Pleistocene Books

“As the discoverer and principal excavator of Murray Springs, [...] Haynes deserves credit for drawing attention to a very curious aspect of the site--a distinct dark layer of soil draped 'like a shrink-wrap,' as Allen West puts it, over the top of the Clovis remains and of the extinct megafauna--including Eloise.
Haynes has identified this 'black mat' (his term) not only at Murray Springs but at dozens of other sites across North America, and was the first to acknowledge its clear and obvious association with the Late Pleistocene Extinction Event. he speaks of the 'remarkable circumstances' surrounding the event, the abrupt die-off on a continental scale of all large mammals 'immediately before deposition of the ... black mat,' and the total absence thereafter of 'mammoth, mastodon, horse, camel, dire wold, American lion, tapir and other [megafauna], as well as Clovis people.'
Haynes notes also that 'The basal black mat contact marks a major climate change from the warm dry climate of the terminal Allerod to the glacially cold Younger Dryas.'
From roughly 18,000 years ago, and for several thousand years thereafter, global temperatures had been slowly but steadily rising and the ice sheets melting. Our ancestors would have had reason to hope that earth's long winter was at last coming to an end and that a new era of congenial climate beckoned. This process of warming became particularly pronounced after about 14,500 years ago. Then suddenly, around 12,800 years ago, the direction of climate change reversed and the world turned dramatically, instantly cold--as cold as it had been at the peak of the Ice Age many thousands of years earlier. This deep freeze--the mysterious epoch now known as the Younger Dryas--lasted for approximately 1,200 years until 11,600 years ago, at which point the climate flipped again, global temperatures shot up rapidly, the remnant ice sheets melted and collapsed into the oceans, and the world became as warm as it is today.”
― Graham Hancock, America Before: The Key to Earth's Lost Civilization