[meteorite-list] Classification tidbits & consequences

From: Herbert Raab <herbert.raab_at_meteoritecentral.com>
Date: Tue Jan 4 11:53:45 2005
Message-ID: <24574.81.223.145.66.1104857623.bloek_at_pwebmail.utanet.at>

Zelimir Gabelica wrote:

> Actually, according to the official nomenclature, LL6 is not
> included in the LL3-7 mention.

The Introduction to the last (and previous) MetBull states:

> Hyphens in petrologic type assignments for chondrites (e.g.,
> "H5-6") indicate the range of types observed in breccias

So a classification of LL3-7 would mean that the the range of
types between LL3 and LL7 wss observerd. But as fas as I under-
stand, the range need not to be observed completely, so LL3-7
could also mean that LL3, LL5, LL6 and LL7 have been observed,
but not LL4, for example.

> One should then rather write "LL3/7", this meaning that all
> types from LL3 to LL7 are present.

Accoridng to the MetBull, "slashes (e.g., "H5/6") indicate
transitional assignments", and I doubt that there would be a
transitional type between LL3 and LL7. :-)

> not clear though whether this implies that LL6 is the impacted
> body or the impactor.

I think this implies that LL6 is the dominant lithology. I think
the question what was the impactor and what was the target is not
easy to answer, and it it would even ask for a definition of
"impactor" and "target". If a small meteoride collides with a large
planet (like the Earth) this is obvious, but when small meteorides
collide (which are possible of similar size) it's not that easy...

Best greetings,

  Herbert Raab
Received on Tue 04 Jan 2005 11:53:43 AM PST