[meteorite-list] Mercury Meteorites - the short list

From: Michael Fowler <mqfowler_at_meteoritecentral.com>
Date: Sat, 06 Aug 2011 10:02:00 -0500
Message-ID: <09965B8B-DC88-43A4-95AD-0B82721F8809_at_mac.com>

Of the candidates below, I like the bencubbinites best, as at least some such as Gujba & HAH 237 are speculated to be the condensation products of a plume of vapor from a high speed impact, and they are high metal.

That said, the key feature I would look for in a class of Mercurian meteorite is a variety of formation ages stretching over at least one or two billion years. Using the same logic that McSween used in 1979 when he proposed that SNC meteorites were from Mars, Large bodies solidify slowly and their magma production spans a long time period. In the case of Earth, up to the present day. Small bodies, like asteroids pretty much lost their magma producing heat within the first 10 to 40 million years max. The moon and mercury being intermediate in size could continue to generate magma for several billion years.

Therefore, any class of meteorites whose ages are all clustered very tightly at 4.564 billion years, the age of the solar system, are almost certainly not from Mercury. Remember that the surface of Mercury is largely regolith generated by impacts over the age of the solar system. Therefore the chances that a meteorite from mercury would sample rock undisturbed since the formation of the solar system seems remote, while one with younger formation ages which is not from the Moon, or Mars would be a prime candidate.

Mike Fowler
Chicago



> Hello again Mercury Nornoids,
>
> Physics, opinions and biases aside ... can we build a concise list of
> Mercury meteorite candidates already in our collections (at least
> wistfully) and play a game to see if we can speculate on them one by
> one - before the scientific press - with information from MESSENGER -
> as candidate meteorites from Mercury? Or, better yet, not eliminate
> one or more ... ;-) ?
>
> 1. Bencubbinites
> 2. Angrites
> 3. GRA 06128 & 06129
> 4. NWA 011 and pairings
> 5. Mercury Meteor (parent body Mercury or Ford?)
>
> Sunnyside up,
> Doug
Received on Sat 06 Aug 2011 11:02:00 AM PDT