Bits from the solar system

[John]

I thought I’d share some piccies and a little info about some of the latest additions to my small collection of meteorite specimens. These are all Achondrite specimens and are igneous in origin. From the Moon we have Dar al Gani 400. Meteorite DAG 400 (as it’s known) was found in Libya in 1998 and comprised a single crusted stone which weighed around 1.4 kg. I believe that it was only the 2^nd meteorite that was positively identified as having come from the Moon which gives it some historical interest. A number of others have since also been categorised as lunar as well of course. Radiometric dating has put the formation age of DAG 400 at around 3 billion years ago – about 1.5 billion years younger than most meteorites which ties in with the Moon being geologically active for longer after it’s formation than smaller bodies. My little slice is wafer thin and only a few mm across but it does show the characteristics of this material quite nicely. It is technically known as Anorthositic Regolith Breccia and is thought to originate from the lunar highlands.

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From Mars we have North West Africa 1068. Meteorite NWA 1068 was found in Morocco in 2001 and only around 580 grams of this stuff exists. It is Martian Shergottite Basalt and is thought to have formed beneath the surface as molten rock cooled around 185 million years ago – very young for a meteorite which is one bit of evidence that made scientists realise that some meteorites had come from Mars – a world tectonically active until comparatively recently unlike the moon and asteroids. It was blasted off the surface of Mars by a significant meteorite impact around 2.2 million years ago and has made it’s way to Earth. My little fragment is around 10mm by 8mm and weighs just 140 milligrams !.

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From the asteriod Vesta we have Tatahouine. The Tatahouine meteorite was seen to fall to Earth near the town of Foam Tatahoune in Tunisia on 27 June 1931. About 13 kg has been recovered, mostly in the form of small fragments like my 3.75 gram specimen. It’s known as the “green meteorite” for reasons you can see from the picture and is technically known as a Diogenite type. For Star Wars fans, yes, George Lucas did name Luke Skywalkers home town after the town in Tunisia and some of the filming for the movies took place not too far from there. Spectrographic analysis has suggested strong links between the Tatahouine meteorite (and other Diogenite meteorites as well) and the asteroid Vesta and the asteroid does show evidence of a major impact crater in the best images we have. The meteorites formation age is 4.55 billion years ago – it’s very old stuff !!.

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Sorry for the lengthy post - I hope it's of some interest - I could ramble on about these for hours as you can probably tell . John

[legion48]

Nice post John, very interesting.

[John]

Nice post John, very interesting.

Thanks. I've just noticed that I've referred to Luke Skywalkers home town wheras it was actually his home planet that was Tatahouine .... oops :oops:

John

[steviejasp]

Thanks for posting that. Very interesting