Hi Mark, John, and List, Since Eric already addressed an error in the first answer regarding the absolute ages of Martian, and lunar meteorites, let me address an error in the second answer:
> Q: How long have these planetary meteorites been on earth? > A: Probably all less than 25,000 years. So we know the rate of finds > from material found that probably fell in recent times. 1 to 1 Humm, this isn't true, at least not for several lunar meteorites in our collections. More recent studies show that some lunaites exhibit remarkably long terrestrial residence ages. For example, the terrestrial age for the lunar breccia Dhofar 025 (and pairings, e.g., Dho 301, 304, and 308) is estimated at 500ka (yes, that's 500,000 or half-a-million years!). Some Antarctic finds are also much, much older than 25ka, such as MAC 88104/88105 that shows a terrestrial age of about 200ka. In fact, most lunaites have terrestrial ages of 10ka (10,000 years) or more, and only a few are thought to have fallen in more or less recent times. I'm not sure regarding the Martian meteorites of which at least four represent witnessed falls - a fact that raises even more questions... All the best, Norbert ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
