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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