Hi Randy,
Fascinating information...thanks. So can this data can help to narrow
down whereabouts on the moon that the various lunar meteorites may have
oiginated...or at least where they didnt come from?
Regards
Graham Ensor
Randy Korotev wrote:
Dear Mr. Ensor:
One of the reasons that Oceanus Procellarum was chosen as the 2nd
Apollo lunar landing site, Apollo 12, was to help answer the red-blue
question. Astronomers had noted that some of the maria of the eastern
part of the Moon were bluish and while those on the west were
reddish. (I use east and west in the terrestrial sense, not the
astronomical sense - east is right, west is left.)
One of the surprises of Apollo 11 (Mare Tranquillitatis) was that the
basalts had very high concentrations of titanium-bearing minerals -
ilmenite (FeO TiO2), ülvospinel (2FeO TiO2), and armalcolite ([Fe,Mg]O
2TiO2), a new mineral that was named after the Apollo 11 astronauts.
Ever since, the Apollo 11 basalts have been called "high-titanium
basalts" (as have the basalts of Apollo 17, which were collected on
the edge of Mare Serenitatis, another blue area, as you note.) The
Apollo 12 basalts had much lower concentrations of Ti. In mare
Tranquillitatis, the Ti minerals dominate the color, making the
basalts blue. At Apollo 12, pyroxene (a Fe,Mg,Ca silicate) dominates
the color, making the basalts red. The color, thus, is dictated by
silicates and oxides of metals (mainly Fe and Ti), not be free metal
from meteorites.
Earth-based spectroscopy of the near side as well as whole-moon
spectroscopy by the Clementine mission show that high-Ti basalts are
really not so common on the Moon. None of the basaltic lunar
meteorites are composed of the high-Ti basalts. They're all "low-Ti
basalts" or "very-low-Ti (VLT) basalts."
Sincerely,
Randy Korotev
At 10:21 05-05-07 Saturday, you wrote:
Hi all,
Not far back there was a discussion on the list about iron contentent
in lunar samples/meteorites and I thought this seemed related.
I have just been sent this email by a friend from my local astronomy
society who is into astrophotography and wondered if any knowledgable
people on the list would like to comment. I have never heard of of
or seen this before and thought it sounded dubious. If anyone is
interested in the photograph I could email it to you.
email below...
Last night (29-04-07) I managed to image the moon and process it in
such a way that it brought out the lunar colours signifying different
types of rock on the surface. There are two images attached to this
email, one is an unprocessed one (almost "black and white" but it is
in fact a colour image!) and the second has had the colour process
done on it.
The images are a stack of 31 frames taken with a C8-NGT/Moonlite CR-1
and a Canon EOS300D/MPCC combination. Each single image was at 100ASA
and exp was 1/200th second. To achieve the colour processed the image
was neutral colour balanced so that when the saturation was adjusted
it didn't favour any one colour. Once done, the saturation was
increased in three stages of +30 and then in a couple stages of +10.
Once the final colour balance was achieved, the image was unsharp
masked and contrast adjusted to achieve the final result.
Checking information on the internet, the colours signify areas of
differing amounts of metal in the basalts on the Mare regions, the
bluer the area the more metal, the oranger the area the less metal.
Mare Tranquilitatis is very blue in comparison to neighbouring Mare
Serenitatis although round the edge of Serenitatis, the metal
composite is higher around the edge of the "shoreline" in comparison
to the centre of the "sea." Mare Humorum (to the lower left) displays
the opposite colourations to Mare Serenitatis. Sinus Iridum, on the
other hand, is very clearly low on metals and has a distinct border
with Oceanus Procellarum plateau and from the processed image Mare
Frigoris, on the northern edge of the lunar face, is low on metal.
Graham Ensor, nr Barwell UK
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Randy L. Korotev phone: (314) 935-5637
Research Associate Professor fax: (314) 935-7361
Washington University in Saint Louis [EMAIL PROTECTED]
Department of Earth & Planetary Sciences http://epsc.wustl.edu/
Everything you need to know about lunar meteorites:
http://meteorites.wustl.edu/lunar/moon_meteorites.htm
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