[meteorite-list] meaning of breccia

[Dave Gheesling]

Thanks for this post, Dr. Rubin.  Sent my earlier comments too quickly, and
was more focused on the fact that list members like you should be commenting
on these sorts of things anyway -- and that private collectors shouldn't be
quoted (misquoted, in this event, or actually quoted when no prior quote
existed at all) as if their supposed opinion matters much anyway. 
All the best,
Dave
www.fallingrocks.com

-----Original Message-----
From: aerubin at ucla.edu [mailto:aerubin at ucla.edu] 
Sent: Tuesday, May 10, 2011 12:23 AM
To: dave at fallingrocks.com
Cc: cdtucson at cox.net; 'meteoritelist'; 'Greg'
Subject: Re: [meteorite-list] meaning of breccia

Just a clarification of the word breccia.  A breccia is a rock that contains
distinct chunks or clasts.  If the clasts are all of the same lithology and
the host is the same lithology as the clasts, the rock is a monomict
breccia.  If the clasts or hosts are from different meteorite groups, the
rock is a polymict breccia.  Wasson coined the term "genomict breccia" for
chondrites that have clasts from the same group but of different petrologic
types (e.g., L5 and L6 clasts in an L-chondrite host). A regolith breccia is
a rock from the surface of its parent body.  A prime example is the
H-chondrite Dimmitt.  In addition to H4 and H5 clasts,the Dimmitt host
contains some H3 material.  There are also some carbonaceous chondrite
clasts (CM and unspecified C3) and an LL5 clast. Regolith breccias are also
typically rich in solar-wind-implanted rare gases and may contain mineral
grains with solar-flare particle tracks.