[meteorite-list] chondrite ungrouped

[Jeff Grossman]

An ungrouped chondrite is a chondrite with properties that do not fit 
into the existing named groups. Right now, this means it is not an H, L, 
LL, R, CI, CM, CV, CO, CK, CH, CB, CR, EH, or EL chondrite.  It is 
something different. There are many ungrouped carbonaceous chondrites, 
and number of ungrouped non-carbonaceous chondrites.

When 2-3 ungrouped chondrites have similar properties, some people call 
this a "grouplet".  These may or may not have well-known names, e.g. "K 
chondrites" (of which there are 2).

When 3-5 ungrouped chondrites have similar properties, somebody usually 
tries to define a new group.  So in this sense, "ungrouped" is a 
temporary designation that will eventually get replaced when collections 
grow, either through meteorite falls or sample returns (assuming that 
the one and only asteroid of this type didn't hit the earth to produce a 
given ungrouped chondrite).

Note also that a significant fraction of ungrouped chondrites that get 
submitted to the nomenclature committee do not get accepted as ungrouped 
chondrites.  This is because "ungroupiness" is not well defined.  
Sometimes there is a fine line between something that belongs to a 
group, but has "anomalous" properties, and something that is different 
enough to get the label "ungrouped."  Even when something gets published 
as ungrouped in the Bulletin, you may later see publications that 
disagree... and vice versa.

Jeff


On 2/24/2013 9:58 PM, habibi abdelaziz wrote:
> hello ,
> i wnat to ask here;
> what is chondrite ungrouped , is that mean anew grouped chondrite,
> something not classified before is there examples
> i got a classifcation as chondrite ungrouped just today
> thanks
> aziz
>
> habibi aziz
> box 70 erfoud 52200 morroco
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