[meteorite-list] Lunar question

From: Randy Korotev <korotev_at_meteoritecentral.com>
Date: Tue, 08 Sep 2009 15:39:31 -0500
Message-ID: <200909082039.n88KdGW27036_at_levee.wustl.edu>

>
>Randy, far be it from me to put words in your fingers, but I recall in an
>earlier (a year or two ago) post from you on lunar regolith breccias, you
>mentioned that in a lunar breccia, the clasts are more or less randomly sized,
>while in most terrestrial breccias, the clasts are mostly of similar sizes
>because of wind, water, or gravity sorting them. (Correct me if I'm
>wrong with
>this addition to your list.)

Darren:

Yes, I should have mentioned that. Most terrestrial sedimentary
rocks are what sedimentologists call "sorted." All grains in a
certain size range are deposited at the same distance from the
shoreline. But, with no wind and water and little gravity, the
fragmental material on the surface of an asteroid or the Moon is not
sorted. There's a continuum from small to big. I think of a lunar
regolith of fragmental breccia as being fractal - it doesn't make any
difference what scale you're look at. It always looks the same.

Unfortunately, terrestrial volcaniclastic rocks are also not well sorted.

Randy Korotev
Received on Tue 08 Sep 2009 04:39:31 PM PDT