[meteorite-list] The (Long) Weekend Warrior: ... Crater Size and Age

From: MEM <mstreman53_at_meteoritecentral.com>
Date: Tue, 19 Oct 2010 22:08:59 -0700 (PDT)
Message-ID: <958155.94580.qm_at_web55208.mail.re4.yahoo.com>

With regard to the range of asteroid sized bodies, average body size is trending
smaller owing to collisions. The solar system has been greatly depleted of
larger bodies as compared to the original populations of planetary/asteroidal
bodies. Collisions, by-in-large, produce multiple "smaller" objects which, over
time, produce even smaller objects and so on. So large impacts "statistically"
point back to a very early solar system with a greater proportion of larger
objects. The impact itself is evidence of depletion.

In general, the more impacts visible on the surface, the relatively longer
exposure that surface has had to impacts. An older surface that hasn't been
renewed by tectonic/volcanic recycling will have more craters and a higher
proportion of larger astroblemes. We date planetary surface geological
activity/age using crater count and overlap statistics with crater sizes
factored in..

Elton



----- Original Message ----
> From: Jonathan E. Dongell <jdongell at cox.net>
> To: Ron Baalke <baalke at zagami.jpl.nasa.gov>; Meteorite Mailing List
><meteorite-list at meteoritecentral.com>
> Sent: Tue, October 19, 2010 9:41:26 PM
> Subject: Re: [meteorite-list] The (Long) Weekend Warrior: Nine Moons, 62 Hours
>(Cassini)
>
> Ron,
> I can understand why more impacts could be an indication of an older
>satellite,
> but could you explain why 'larger' impacts is also an indication of older, as
>well.
> Thank you, in advance.
> Jonathan Dongell
> IMCA 3922
Received on Wed 20 Oct 2010 01:08:59 AM PDT