[meteorite-list] meaning of breccia

From: aerubin at ucla.edu <aerubin_at_meteoritecentral.com>
Date: Mon, 09 May 2011 21:22:49 -0700
Message-ID: <20110509212249.24082ftvoncd3v6g_at_mail.ucla.edu>

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.
Received on Tue 10 May 2011 12:22:49 AM PDT