[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Vredefort



> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Richard W Travsky
>
> On Wed, 24 Nov 1999, Ilja Nieuwland wrote:
> > I am certainly no expert at this, but doesn't all this rather beg the
> question how much impact the earth can bear before its structural
> integrity
> is compromised? If a 'mere' one-mile diameter projectile can
> produce all this
> maehem (one million Krakatoa explosions is quite expressive),
> then where would
> a five of more-diameter comet leave us?
>
> Well, from the standpoint of a biologic, yes, it's bad, but look at the
> moon. It took some pretty big hits and it's a lot smaller than the Earth.

Actually, you can look at the moon to see the effects of sizable impacts on
Earth!

The generally accepted hypothesis for the formation of the Earth was an
impact on the proto-Earth by a MARS-sized body: the resultant material
splashed out of Earth & the Mars-sized body recoalesced as the Moon.

This would have necessarily happened prior to 4.0 Ga (Gigaannum: aka billion
years ago): this kind of impact would have obliterated the entire crust of
the Earth.

Even the impact of a Texas-sized body (ala the movie Armageddon) would rip
through (and possibly overturn large portions of) the lithosphere, and be a
Biota-terminating event.


                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-314-7843