[meteorite-list] Analysis of meteorites with an SEM

From: ensoramanda <ensoramanda_at_meteoritecentral.com>
Date: Sun, 24 Feb 2008 02:26:49 +0000
Message-ID: <47C0D5E9.5020009_at_ntlworld.com>

Hi,

Just tested out the download method that was suggested to me....it does
seem to work from the link...but I apologise for the method and all the
ads you are subjected to...I was unaware they might be that bad when
someone showed me the site.

Regards

Graham

ensoramanda wrote:

> Hi all,
>
> Over the years I have always enjoyed all the images people have posted
> showing meteorites in many ways, beautiful photographs, thin sections
> etc etc. I wish to share some images and data of another kind showing
> meteorites in another light.
>
> Yesterday I helped my local University with their open day by setting
> up a display of some of my meteorite collection and talking to
> students and on local radio. In the afternoon I was let loose in their
> labs where we cut a couple of meteorites, a NWA 4576 mesosiderite and
> an unclassified piece (ordinary chondrite). A great feeling being the
> first to see the inside of a meteorite since it was formed.
>
> Then I was shown how to use their SEM (scanning electron microscope)
> and left to collect data from my samples....a fantastic priviledge to
> be allowed to scan around my own pieces like that. I ended up with
> nearly 40 images and related graphs showing the elemental compositions
> of various parts.
>
> For those not familiar with an SEM, the samples are loaded into a
> vaccum chamber and you then drive the samples around on the computer
> screen looking for unusual areas to point the cursor at. Once the
> areas or points are chosen the SEM can then almost instantly give you
> a graph showing the elements and their percentages...from which a
> trained eye can work out the minerals present.
>
> Not being trained in any way to do this then this where I lack the
> knowledge to interperate the data...although I can take a good guess
> at which is likely to show olivine, troilite. The lighter areas of the
> images are the nickel iron.
>
> If anyone on the list has had experince interpereting this sort of
> data I would be interested in your comments on what some of the data
> shows. For others on the list it might just be an opportunity to look
> at some images of meteorites in another way.
> So feel free to download the word document (nearly 7 meg) and have a
> look if you wish.
>
> http://www.gigasize.com/get.php?d=pz9y3b013tb
>
> (I hope this link works)
>
> The first 7 pages are sample 1, the chondrite, and the rest are NWA
> 4576...which seems to be the most interesting.
> The 2 pages of percentages show 2 areas of Nickel Iron which I guess
> may be Taenite and Kamacite due to the different nickel to iron ratios.
>
> I am intrigued by the areas showing carbon dots and the areas with
> chlorine and iron and oxygen which I presume are due to weathering?
>
> I will take some photographs of the samples as cut if anyone would
> like to see the slices and end cuts.
>
> Graham Ensor, Nr Barwell, UK
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Received on Sat 23 Feb 2008 09:26:49 PM PST