Re: Stone tools

Phillip Bigelow (
Wed, 22 Jan 1997 21:34:03 -0800 wrote:
> In reguards to the stone tools which were recently found
> and supposidly date back millions of years,how do you date
> these items? Can I not make a tool today out of a rock that is
> millions of years old? How do you differentiate the rock from
> the tool? I would really like to know just how they can come to
> such a conclusion!

The rocks in the region were dated using radioisotope/daughter ratios
(or possibly fission-track; I don't know the exact radiometric
technique because I haven't yet read the paper).

Radiometric dating techniques can be relatively accurate, and
frequently have an error of only +/- 10-20 kys on an age
of 2 mya.

The tools (apparently, hundreds of specimens or ?thousands?)
were collected in NE Ethiopia from sediments dated somewhere
around 2.5 mya (roughly). This find pushes back the hominid
(?Homo) use of tools by a couple hundred thousand years.

Read all about it in this week's issue of the journal _Nature_.