[meteorite-list] Ordovician Meteorites...was New or maybe oldQUESTION???

[star-bits at tx.rr.com]

---- "Sterling K. Webb" <sterling_k_webb at sbcglobal.net> wrote:

<And all tektites have an original Rb/Sr melt date of 440-480 million years 
ago. All just a coincidence, of course... >

Where does this information come from?   It does not seem even remotely possible.   No tektites are this old.    All tektites originated as melted terrestrial material.   How do you postulate a "melt date" which precedes a later melting?   You can't even get a date by backing out the Rb/Sr from the known terrestrial impacted material because the SE Asia impact site is not known.   

Additionally this means that all tektite forming impacts were L chondrites, no irons, no H chondrites, no carbonaceous etc.   This is certainly possible but seems unlikely.   Whether a tektite is formed depends on the impacted material and not on the composition of the impactor.

 --
Eric Olson
7682 Firethorn Dr
Fayetteville, NC 28311

http://www.star-bits.com