Re: Bones, Rocks and UV

Bart Torbert wrote:
> Hello,
>
> I need help in dealing with an attempt to apply a dating technique
> standard in forensics to rock art.  Yes, this is going to be a bit
> bizzare, but this is something quite serious.
>
> Of late I have been working with two European university professors. 
> One is Peter Pieper (don't laugh, that is his real name) of Dusseldorf
> Univeristy, Germany and Ian Kirby of Laussanne Univeristy,
> Switzerland.  Pieper teaches archaological and criminal forensics. 
> Kirby teaches various topics dealing with the development of the
> English language.  Both are also quite expert at Old Norse and love
> runestones.
>
> Within the forensics community there is a test that is applied to
> bones to determine if they are old or young.  The test is conducted by
> shining a UV light on the bones.  If the bones are less than a hundred
> years old, any breaks that occured in them (like when the person was
> killed) will fluoresce.  Sort of weird sounding, but quite real.  Here
> is a link to a forensics page that mentions this.
> http://www.dundee.ac.uk/forensicmedicine/llb/ident.htm


Don't they know why?


> My first question is why would this work?  Bone is essentially calcium
> carbonate.  Some of the nicest fluorescent samples are of calcite. 
> But is calcite inately fluorescent or only so if there are the right
> sort of impurities in it?  If calcite is not inately fluoresent, then
> bone, regular limestone, etc. should not be fluorescent.  So why would
> broken bone flouresce and do so for so long a period of time?


I wonder why it would LOSE its fluoresence.(assuming no isotopic 
material is involved).

> Kirby and Pieper are now trying to extend this technique to rock art. 
> They claim they have tested this approach on various types of rocks
> and under conditions where the age of a carving (like on gravestones)
> was known.

This seems like a good first step.

  They are quite satisfied that they have something that
> works.  I am trying to figure out if there is a theoretical  basis for
> it to work.

I have heard of 'shocked quartz' helping to determine meteoric impact 
sites, but that is a physivcal change and other information is used to 
determine time frames.


> I was with them in Oklahoma a couple of weeks ago.  We examined a
> piece of rock art that is documented to have been seen as early as the
> 1830's.  On the stone was also some more modern looking "graffitti". 
> Also there was a spot on the rock where a sample of the stone was
> removed two months ago for geological analyis. The graffitti and the
> sample locale fluoresced, the older artwork did not.  The stone
> involved here was a sandstone that had gone through some low grade
> metamorphism and was quite sturdy.

Is that the Heavener Runestone? I always wanted to visit it.


> So does quartz act like calcite where it is not inately fluorescent,
> but if it is damaged, will it glow for some period of time?  What
> mechanism would allow damaged crystals to fluoresce?  Would this work
> for all minerals or just a select few.

Should be easy enough to test. The question ,again, is what would cause 
this phenomena to be temporary(100years is very quick in geologigic terms)


> If this technique works it would be a big gain to the study of rock
> art.  It would be nice if the technique weren't so crude in the date
> cutoff.  You would only know if the art was older or younger than a
> century.  But for many of the more controversial sites, the person
> promoting the "find" is often accused of creating the rock art
> themselves as some sort of attention getting scheme.  If Kirby and
> Pieper's technique works, then there would at least be no question
> whether something is an authentic ancient artifact or a modern hoax.
>
> I can provide more details as needed about all of this.  I just wanted
> to present the basic problem to mineralogists for their input.
>
> Thanks ahead of time 

I think there is probably a lot of good techniques used by 
archaeologists studying spearpoints and other stone weapons/tools. There 
are of course a lot of folks trying desperately to pass off new points 
as old (sorta the seedy underbelly of the flintknapping hobby) and I 
think there are some effective copies. You should contact some of those 
guys. They prbably know the most about how worked stone changes with time.


Carl
1 Lucky Texan




> Bart Torbert
> [EMAIL PROTECTED]


--
to reply, change  ( .not)  to  ( .net)