John: I am sure Adam will have something to add but here is a good description of Ureilites http://www.daviddarling.info/encyclopedia/U/ureilite.html
I always thought that all ureilites were "primitive". So someone please enlighten us! Matt Morgan -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, September 28, 2004 10:51 AM To: [EMAIL PROTECTED] Subject: [meteorite-list] primitive Ureilite ? Hello all, I was reading one of Adam's auctions this morning and noticed the word primitive attached to the word Ureilite and began to wonder what was the latest status on Ureilites being considered "primitive". I know the word is used with primitive materials like Acapulcoites and Lodranites because their age is suggested at the chondrite level of 4.5+ billion years. I believe this reference for Ureilites infers the involvement of pre-solar or solar parts such as the diamonds versus a formation age of 4.5 billion years. Or maybe I'm wrong about that. At one time the diamonds were thought to be shock/pressure related, but recently Ureilites with low-shock values have been found that has scientists thinking that the diamonds came from some other source. What is considered the formation age of Ureilites? And does that age in itself make them primitive, or does the parts/pieces make them considered primitive? Curious, John/JD ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
