An Article In Meteorite-Times Magazine
by Tom Phillips

NWA 4901 Ungrouped Achondrite

NWA 4901 is paired to the famous NWA 011. NWA 011 has generated a lot of interest and articles. It is thought to be a likely Mercurian candidate.

Here is a link to an article written by Dr David Whitehouse, BBC News Online science editor

http://news.bbc.co.uk/1/hi/sci/tech/1991394.stm

There are several pairings to NWA 4901. Greg Hupe has worked with most of them! He had a great write up on NWA 4587 that he shared with me. This is his description.

"NWA 4587, an Ungrouped Achondrite purchased in Morocco in June 2006. This unusual meteorite is paired to NWA 011, which was first thought to be an unusual eucrite or even from the planet Mercury! Scientific analysis performed since then (including multiple measurements of oxygen isotopes) suggests that NWA 011 and its pairings probably are rare samples from a different and somewhat large parent body other than 4 Vesta, which also may be the source of CR chondrites. The officially classified pairings include; NWA 011(40g), NWA 2400(137g) and NWA 2976(219g). NWA 4587 is the largest of all the pairings at 530 grams, making the total combined weight 926 grams."

Image of Complete 530-gram NWA 4587 Individual:
http://www.lunarrock.com/nwa4587/nwa4587.jpg

Image of 18.8-gram Complete Slice:
http://www.lunarrock.com/nwa4587/nwa4587slice.jpg

3-D Video of uncut 530-gram NWA 4587:
http://www.lunarrock.com/nwa4587/nwa4587video.avi

I have received emails suggesting that, if I used lower magnifications and worked in standard polarized light, my micrographs would be more useful in standard petrographic analysis. I agree! However, I am looking for the beautiful features hidden in the smaller detail. I like to think of it as art.

I have produced some micrographs (as a special request) to be used in teaching or presentations that are taken in "standard methods". When I have those images available, I will try to fit them in.

This set is taken with a field of view of 4.40 mm. The shots break down like this:

1: plane polarized light
2: partially cross polarized light (-90 degrees)
3: fully cross polarized light
4: fully cross polarized light with a 1/4 wave retardation plate + 45 degrees
5: fully cross polarized light with a 1/4 wave retardation plate - 45 degrees


1: plane polarized light



2: partially cross polarized light (-90 degrees)


3: fully cross polarized light


4: fully cross polarized light with a 1/4 wave retardation plate + 45 degrees


5: fully cross polarized light with a 1/4 wave retardation plate - 45 degrees


OK, all of these next images are taken in full cross polarized transmitted light WITH a retardation plate rotated to what ever looks good!

Field of view of 0.40mm (approximately 160X magnification)









 

Field of view 0.25 mm (approximately 400X magnification)










Tom Phillips can be reached by email at:/font>
STARSANDSCOPES@aol.com

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