This 4,000 years ago event occurs at the same time as the beginning of the Monsoon Winds into India ~ which allowed the vast central massif forests to dry out and allow human settlement.
It is also coincident with a little known event ~ Lake Erie shrank to its present size. Before this time it extended nearly all the way to the Western boundary of present day Indiana. Something happened and the water level dropped, the lake shrank, and bingo it took on its current appearance.
It's probably safe to say that there was a lengthy period of droughts around the world. Most likely seasons got shorter and the world cooled.
The genetic transformations were what they always are during those events ~ the guys from the North moved South!
Many geologists believe the monsoon first became strong around 8 million years ago based on records from the Arabian Sea and the record of wind-blown dust in the Loess Plateau of China.
More recently, plant fossils in China and new long-duration sediment records from the South China Sea led to a timing of the monsoon starting 1520 million years ago and linked to early Tibetan uplift.[9] "
muawiyah: "...also coincident with a little known event ~ Lake Erie shrank to its present size.
Before this time it extended nearly all the way to the Western boundary of present day Indiana.
Something happened and the water level dropped, the lake shrank, and bingo it took on its current appearance. "
"As many as three glaciers advanced and retreated over the land causing temporary lakes to form in the time periods in between each of them.
Because each lake had a different volume of water their shorelines rested at differing elevations.
The last of these lakes to form, Lake Warren, existed between about 13,000 and 12,000 years ago.
It was deeper than the current Lake Erie, so its shoreline existed about eight miles (13 km) inland from the modern one."
Current Niagara Falls formed around 10,000 years ago.
muawiyah: "It's probably safe to say that there was a lengthy period of droughts around the world.
Most likely seasons got shorter and the world cooled."
But so long as we've properly identified your words as mythology and not science, then I'm perfectly happy with what you've said here.
A thousand years from now the inhabitants of Europostan aren’t going to be wondering why it happened in this era.