Volcano !

Beagle · Post by **Beagle** » Fri Jul 06, 2007 8:21 pm

http://johnhawks.net/weblog/reviews/arc ... _2007.html

John Hawks weighs in on topic: At Last, The Death of the Toba Bottleneck Theory!

Post by **Minimalist** » Fri Jul 06, 2007 8:29 pm

In the meantime, we can forget about the cataclysmic effect of Toba on the poor hominids.

Beagle · Post by **Beagle** » Fri Jul 06, 2007 8:35 pm

Well guys, it seems we have a mystery without a theory then. Why the lack of genetic diversity among humans? Plenty to ponder this summer.

I'm not up for a brain cramp tonight though.

Post by **Minimalist** » Fri Jul 06, 2007 11:09 pm

If they were wrong about the eruption maybe they are wrong about the lack of diversity?

Rokcet Scientist · Post by **Rokcet Scientist** » Sat Jul 07, 2007 2:00 am

Minimalist wrote:
Everyone west of the Great Rift Valley?
Apparently, there weren't any.

Where had they gone then?

Digit · Post by **Digit** » Sat Jul 07, 2007 2:25 am

One thing I learned as a supervisor in industry was never to back yourself into a corner, always leave yourself an escape route. I have never understood why these experts are so damn rigid in their opinions. Don't they realise how stupid they look when somebody pulls the rug out from under?

War Arrow · Post by **War Arrow** » Sat Jul 07, 2007 3:59 am

It's that falsehood that maintaining an open mind indicates weakness. You think something is right and even if you're only 98% certain, admitting that 2% will reveal you as a dunderhead. This principle is observable when I say to my girlfriend 'Darling, it is 12;30 and as I have to be at work in 5 and a half hours time I rather fancy I shall retire forthwith seeing as 4 hours sleep does not seem an overly generous quota of rest,' which apparently means there's room for negotiation on whether or not I selfishly go to bed and thus deliberately dump big callous buckets of shit on the end of an otherwise romantic evening when "cuddles" are surely more important (that wasn't a euphamism, I really do mean "cuddles") than me thinking only of myself again. Mind you, thinking about it, I don't think any of the scientists I really respect adopt the THIS IS RIGHT approach, even when chances are they probably are.

Post by **Minimalist** » Sat Jul 07, 2007 9:22 am

Don't they realise how stupid they look when somebody pulls the rug out from under?

Apparently not.

Beagle · Post by **Beagle** » Tue Sep 04, 2007 4:05 pm

http://www.geotimes.org/sept07/article. ... ption.html

Seventy-four-thousand years ago, Indonesia’s Mount Toba erupted, spreading ash from the Arabian Sea to the South China Sea. Using data from ice cores, researchers have concluded this eruption — Earth’s largest in the past 2 million years — drastically altered the world’s climate and caused a six-year-long volcanic winter in some parts of the world. Correlating the date of the eruption to evidence of a genetic bottleneck in the modern human population around the same time, some researchers suggested that populations of modern humans (Homo sapiens) that had previously expanded out of Africa were unable to cope with these changes, and thus experienced huge population declines everywhere except in tropical, mainly African, refuges. Now, Michael Petraglia, an archaeologist at the University of Cambridge in the United Kingdom, says his team has found evidence to the contrary. Excavating in Jwalapuram in southeastern India, Petraglia and his crew discovered stone tools that they say show not only that modern humans were living in the area both before and shortly after the eruption, but that they left Africa via a different route than is commonly thought.

Another article about humans in India surviving Toba.

kbs2244 · Post by **kbs2244** » Tue Sep 04, 2007 4:20 pm

What are the wind currents and local geography in the area?
Could they be in a “wind shadow” that let the ash flow around them?
A “ micro climate” pocket of survivability?

Digit · Post by **Digit** » Tue Sep 04, 2007 4:26 pm

That's an intelligent question KB, kindly go to the back of the class and stick to asking questions that support the status quo!

Like I asked asked earlier about the comet that is supposed to have eliminated the mega fuana of NA, they say it could 'easily have done so', then pass on without explaining how.

Beagle · Post by **Beagle** » Tue Sep 04, 2007 4:27 pm

The article says that human tools were found below and above the layer of ash from Toba. Since there was a layer of ash, it appears that they got the full effect.

Digit · Post by **Digit** » Tue Sep 04, 2007 4:44 pm

Sombody help me on this! Toba is in Indonesia? How would the ash cloud have spread both east and west?
And if the limits are as stated that doesn't quite match the idea of world wide climate change does it?

Beagle · Post by **Beagle** » Tue Sep 04, 2007 4:47 pm

It's theorized that it put so much ash in the atmosphere that it caused a "nuclear" winter in which plants and animals died. Obviously something wrong with that theory.

Digit · Post by **Digit** » Tue Sep 04, 2007 4:50 pm

But for the ash to travel any great distance Beag it's got to reach the Jet Stream surely? And that's unlikely to spread it east and west.