[meteorite-list] Impact Structures - Simple vs Complex?

From: Larry Lebofsky <lebofsky_at_meteoritecentral.com>
Date: Fri Mar 17 13:26:23 2006
Message-ID: <1142573893.441a4b457be57_at_hindmost.LPL.Arizona.EDU>

Hi all:

I know that I am responding to my own message, but now have hard numbers
(spoke to someone who actually knows what is happening).

1. The size of the transition from simple to complex craters goes as 1/g
(gravity), with a little having to do with the material.

Therefore:

2. The transitions:

Earth: 3 km
Mars: 7 km
Mercury: 10 km
Moon: 17 km

Larry

Quoting Larry Lebofsky <lebofsky_at_lpl.arizona.edu>:

> Hi Jeff:
>
> It has been some time since I studied this (will ask around here at the Lunar
>
> and Planetary Science Conference), but I think that it is basically: size
> matters!
>
> How big of a hole can you maintain in a bowl shape before gravity and the
> strength of the material take over?
>
> Larry
>
> Quoting Jeff Kuyken <info_at_meteorites.com.au>:
>
> > Here's a question for those of you more familiar with impact structures on
> > Earth. I believe I saw somewhere that craters fall into 2 main categories?
> > simple and Complex with the later having a central uplift, concentric
> rings,
> > etc among other things.
> >
> > My question is: How small can a complex crater be? Is there a definitive
> > size restraint or does it completely depend on a multitude of variables
> such
> > as the make-up of the impacting body, velocity, impact angle, target rock,
> > etc?
> >
> > Any help is appreciated,
> >
> > Jeff Kuyken
> > Meteorites Australia
> > www.meteorites.com.au
> >
> >
> >
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> >
>
>
> --
> Dr. Larry A. Lebofsky
> Senior Research Scientist
> Co-editor, Meteorite
>
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Received on Fri 17 Mar 2006 12:38:13 AM PST