Edge grinding at 35KY BP in Australia

[kbs2244]

From today’s news page.

http://www.theage.com.au/national/35000 ... rom=age_sb

35,000-year-old axe head places Aboriginal ancestors at the cutting edge of technology

What makes this one different, besides its age, is that the edge was done by grinding, not flaking.

I have never heard of that with stone tools.
It is, of course, the way to sharpen a metal edge.

[Digit]

Frankly I'm rather surprised that grinding is supposed to be that late.

Roy.

[Minimalist]

''We've got two dates from charcoal taken from above where the axe was found and two from below and they match exactly,'' Dr David said.

I'm always a tad skeptical about dates from the "associated organic material" camp.

[kbs2244]

I agree Min.
Real old dates make me nervous.

But the grinding vs. flaking it important to me.
It is the only way to sharpen a metal edge.
But metal technology was a long time coming.

When, where, and how, did the connection take place?

[Rokcet Scientist]

the basalt axe piece measuring 4 centimetres in length has been radio-carbon dated at 35,000 years old.

How do you radio-carbon date a non-organic material that was formed hundreds of millions of years ago in tectonic/volcanic processes?

[Minimalist]

By dating the charcoal found above and below it and assuming that everything is as it has always been.

You know what they say about "assume."

[Rokcet Scientist]

By dating the charcoal found above and below it and assuming that everything is as it has always been.

You know what they say about "assume."

Then it was stratum dating, not radio-carbon dating.
So I wonder what else in that article was bent...

[Minimalist]

It's both. They carbon date the charcoal because they know as well as you that they can't date rocks. It's the assumption that the ground has not been disturbed that always bothers me.

[Digit]

Although it's obviously not conclusive Min, but if the ground above post dates the ground below, then there is every chance that the two dates do follow each other. The only alternative that I can see would be that the ground above had been disturbed right down to the earlier date with the disturbance stopping just there, not impossible, but most unlikely I would suggest.

Roy.