[meteorite-list] Any Meteorites of Earth Origin?

From: meteorites_at_space.com <meteorites_at_meteoritecentral.com>
Date: Thu Apr 22 09:47:10 2004
Message-ID: <20011112154642.12303.cpmta_at_c000.snv.cp.net>

On Sun, 11 November 2001, Jeff Grossman wrote:

>
> At 04:34 PM 11/11/2001, meteorites_at_space.com wrote:
> >On Sun, 11 November 2001, Jeff Grossman wrote:
> >
> > >
> > > Alan Rubin and I wrote a definition of "meteorite" for Meteorite! a while
> > > back that allowed for terrestrial meteorites. Our current thinking is
> > that
> > > the object would have to have left Earth by natural processes
> > > (impact-launching seems the only option, although this is highly
> > > improbable), either by achieving escape velocity, or by insertion into
> > > Earth orbit via some secondary change to its trajectory (we want to
> > > eliminate material on ballistic paths that take it immediately back to
> > > Earth, e.g., tektites). If such material later reaccretes to Earth or
> > > accretes to another body (like the Moon or an asteroid), we would define
> > > this as a terrestrial meteorite.
> > >
> > > Of course, we already have terrestrial meteorites in our collections if
> > the
> > > well-accepted theory of lunar formation is correct. But that's just
> > > semantics. There is no evidence for more recent events on Earth producing
> > > terrestrial meteorites.
> > >
> > > jeff
> >
> >
> >Tektites, the Australites in particular are "terrestrial meteorites."
> >
> >Steve Schoner.
> >AMS
>
> What makes you say that?
>
> Jeff
>
> Dr. Jeffrey N. Grossman phone: (703) 648-6184
> US Geological Survey fax: (703) 648-6383
> 954 National Center
> Reston, VA 20192, USA
>


The morphological structure of the Australites (Flanged buttons, flanged dumbells, propeller types) all indicate hypersonic entry into the atmosphere. They were produced in SE Asia, ejected to high altitude, perhpas thousands of miles, traveled in ballistic trajectories to fall in Australia where they are found today.

The closest thing to "terrestrial meteorites" if you ask me.

As for the others, the ones that did not achieve hypersonic velocities enough to escape the thicker portions of the Earth's atmosphere-- I don't think that these can be by the definition that you stated considered "terrestrial meteorites"

Steve Schoner, AMS

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Received on Mon 12 Nov 2001 10:46:42 AM PST