[meteorite-list] Iridium (+ Osmium ? + Technetium ?) measuring and testing

From: Michael Bross <element33_at_meteoritecentral.com>
Date: Sun, 15 Mar 2009 03:25:05 +0100
Message-ID: <005d01c9a515$41299430$db9d215a_at_Inspiron8200>

Hello List and Darren (re: 2 articles you posted in the past on the list)
Sorry, this will be a rather long post ! But please, I have "newby"
questions.
I hope for a discussion even if West and now the Denmark finds attract most
of the posts.

AS: I know... I haven't presented myself yet. Briefly, I was born in
Strasbourg,
France, May 1961. Engineer in Agronomy, I spent most of my life overseas.
I returned recently to France after several years in USA (NY + Long Island)
Environmental consultant for many years, mainly for soil and groundwater
pollution
data management, mapping and 3D visualization, I plan now to open a farm, in
France or elsewhere.

My interest in meteorites is very new on the serious side, and being a
Taurus ! I spent a lot of time
 the last 3 weeks researching, getting informed etc... not to be too naive
when posting.
So, I read a lot.... First is the beauty of most of the meteorite: shapes
and differentiations.
But also, what makes meteorites different from Earth rocks/materials.

I am very happy to have joined your community, having exchanged emails with
some of the members on
the list and hoping to meet most of you sooner or later like in Ensisheim
this next June,
and enjoying the West discovery and hunt etc...

Now, Iridium: (or Osmium, or any other main element for measuring and
testing meteorites)
Searching the archives of the List, I got 279 hits for Ir, BUT mainly about
Ir flares, the Iridium satellite
network and Ir occuring in craters. I went thru about 1/2 of them.
You know Taurus/Bulls: stuborn, "hard" working, difficult to stop when they
start...! :)

Darren, you had 2 posts:
1- "Possible Ohio crater" in Apr. 2005: not one response to it !
Another Mecca or alike ?
2- "The wonderful wizards of Osmium" (Apr 2008): few answers, but nothing
about the unique extraterrestrial
signature of Osmium compared to Iridium (end of the post)

What I know so far:
- Iridium content in the Earth's crust is 0.001 ppm (or 1 ppb). Much more in
the core.
- In meteorites it is 0.5 ppm or much more. The Willamette at the AMNH in
NYC has 4.7 ppm Iridium.
= 500 or thousands time more.

A- measuring on the field/ meteorite finding/ first testing:
I read often that finders/hunters use magnets. What about a metal detector
measuring Iridium ?
or is Iridium detection too close to other elements, or too small in content
to be singled out ?
and what about Osmium ? or Technetium ?

B- testing
How is Iridium (or Osmium, or Technetium) analysed and tested ?
Is there any non-invasive way to test one or more of them, to keep the
meteorite "as is" ?

It is 3 am for me, editing this post to be as concise as possible.
Hoping for some answers...

Have a great day
Michael B, France
Received on Sat 14 Mar 2009 10:25:05 PM PDT