[meteorite-list] Timing is Everything

[Gerald Flaherty]

Thanks Kevin, it helps clarify[slightly] an issue that's screaming for 
investigation. Jerry Flaherty
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From: <MARSROX at aol.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Wednesday, April 20, 2005 4:52 PM
Subject: [meteorite-list] Timing is Everything


> Thanks to Mike Jensen for the heads-up on the  paper newly published by 
> Dr.
> Jeff Grossman and Adrian Brearley refining the  measurement of 
> classification
> for chondrites.
>
> In the last couple of days,  including today, I've been working on a 
> feature
> for "Meteorite"  magazine that includes discussions I had with Dr. 
> Brigitte
> Zanda, the  curator of the NHM met collection in Paris about her research 
> in
> chondrule  formation. We talked about her discovery of chondrules in a 
> plastic
> state during  formation in Semarkona LL3.0, perhaps the most primitive
> chondrite.
>
> The  most obvious point here is that chondrules were observed in formation
> that are  not spheres. It's an exciting discovery in today's most 
> happenin'
> meteorite  research area - the origins of chondrules. You can read more of 
> this
> discussion  in "Meteorite" come August.
>
> One side area of interest with all this, is  that petrology is now 
> determined
> by using "thermaluminesence." This technique is  a bit more sophisticated
> than when one looks at a slice of something and  expertly guesses, "Oh, 
> that
> looks like a L5."
>
> A discussion has risen  about thermaluminesence measuring because it's
> possible that terrestrial  weathering can alter the outcome of a 
> pre-terrestrial
> event, changing what  observers think is a most primitive 3.0 to a 3.2 or 
> 3.4.
>
> On my first  quick read of this (I have a meeting in 30 minutes), Jeff and
> Adrian's paper  seems to propose extremely accurate measuring of petrology 
> in
> type 1 chondrules  by combining electron microscopy and 
> cathodoluminescence in
> their observations.  The resultant measurements would be several times 
> more
> accurate than present  thermaluminesence techniques, i.e. resulting in
> petrology's of 3.05, 3.10, etc.,  instead of just 3.0 or 3.2.
>
> However, I'm assuming that  cathodoluminescence (can't type that too many
> times without misspelling) is  different from thermaluminesence (and I'm 
> sure
> someone will soon let me know if  it isn't - smiley face here). But this 
> is great
> work and seems to me to be  exciting news.
>
> Kevin Kichinka
>
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