[meteorite-list] Analysis of meteorites with an SEM

[ensoramanda]

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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