[JohnBovenmyer]

Dating is important as one major known catastrophic event happened at roughly that time. The most recent eruption of a super volcano, Toba in Indonesia happened about 75k years ago and blew a hole 60 by 18 miles wide and up to a mile deep there. Toba is by far the largest geologic event of the last 100k years. Shooting all that material into the atmosphere certainly messed up the world climate for several years. If this African drought happened right after Toba blew than look no further for its explanation. Also look no further than Toba for the reduced human population of that time that genetic research implies. It had to have a major effect on mankind at the time, but I don't think we have any human records, not even the legends of the Australian aborigines, that go back quite that far.

[blam]

"Also look no further than Toba for the reduced human population of that time that genetic research implies. It had to have a major effect on mankind at the time, but I don't think we have any human records, not even the legends of the Australian aborigines, that go back quite that far."

I agree. Probably Toba. I've seen estimates as low as 2,000 for the worldwide human population after Toba. Most are closer to 5,000 with some ranging up to 10,000. Even so, not many people for the whole world.

The Last Glacial Maximum(LGM) 18-23,000 years ago thinned out the human population dramatically too.

[expatpat]

The PBS program I referred to was talking about a drought and drop in sea-level that resulted from an Ice Age, when glaciers bound up a great deal of the water in the atmosphere and the oceans, forcing those in interior Africa like the clicking bushmen we are descended from to move.

[gleeaikin]

"The last glacial maximum 18,000 to 23,000 years ago."

There were a number of major volcanic events from 28 kya to 22 kya, that appeared to cause a stepwise decrease in temperatures. The one for 22,000 years ago was Mt. Sakura-jima in Japan. It left a crater 15 miles in diameter, which is now a great bay with a much smaller volcano of the same name on one side. I would love to get time and size data on a few other possible major volcanic events for that period.