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Re: Earth meteorites?

	Earth meteorites would very difficult to recognize indeed. It 
seems that with out seeing it fall, they would virtualy 
unrecognizable,due to the fact that they would resemble tektites. Perhaps 
the following story might help. 
	I used to work at the Field Museum in Chicago as volunteer for 
the Geology department. I did mostly paleontological work, as I was an 
undergraduate in paleontology, however meteorites always facinated me. 
	One day I was walking through the back area looking for a fossil to 
be put on display in a new exhibit being built, when I encountered a 
gentleman by the name of Ignacio Cassanova, the geology department's 
meteoriticist. 
	I had a question about tektites, and thought I would ask it, because  
I had the opportunity. I figured I would meet with some offence to my 
question, as Dr. Cassanova may have had other things on his agenda. 
Instead he stoped, and answered my question, quite fully. 
	I asked:" Are tektites from outer space, or did they originate on 
Earth?" Dr. Casanova looked at me, and just began to speak without an 
inflection of disdain, and began to talk to me as a teacher to a student.
	Here is what he said(paraphrased, as I don't remember all): 
"Tektites are both impact ejecta, and meteorites. For example, the 
Martian meteorites are meteorites to us because they landed on Earth, but 
if a Martian were to have one fall back on his/her/it's planet, it would 
be a tektite. It is all in the frame of reference. If, for example an 
Austrailite landed on Mars, then they would have an Earth meteorite."
	I just wanted to use the above as a philosophical foundation for 
the answer to the question posed by Mr. Baalke. Earth meteorites are a 
distinct possibility. I would argue in favor of such phenomenom, due to 
the fact that impacts can throw large portions of crust into the the 
atmosphere, and into outer space. 
	Now, I would also argue that what is being ejected is in a molten 
state, as an impact would have to be large enough to have enough power to 
overcome the Earths gravitational escape velocity. This would mean that 
silicate minerals would have to melt, due to the pressure and the heat 
involved by such an impact.
	Finally I would argue that a Earth meteorite would necesarily be 
of a glassy state, and not resemble Earth rocks, except obsidian. In my 
arguement, I would point out that it is possible a lot of material from 
past impacts may now be in an orbit between the Moon and Earth, and even 
possible for some to be in orbit around the Sun. 
	I have used the phrase"I would argue..." because this is 
something I forsee as a major debate, if anybody were to look at it 
closely. To summarize what I have stated: Yes we can have Earth meteorites, 
but the would most likely resemble tektites, due to the ejection, and the 
force need to escape Earths gravitation. I hope that this was helpful in 
providing you with an answer.

Frank Stroik
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