[meteorite-list] NEW LUNAR monzogabbro meteorite looks like aShergottite

From: Thaddeus Besedin <endophasy_at_meteoritecentral.com>
Date: Thu, 1 Mar 2007 01:36:33 -0800 (PST)
Message-ID: <83196.32030.qm_at_web62508.mail.re1.yahoo.com>

Weathering processes on the moon are primarily related to solar and impact processes, so mantle material, as well as intrusive monzogabbroic material equivalent to mugearitic rock in extrusive terrestrial contexts will have been present on the lunar surface in variable concentrations in respect to magnitude of impact, although relationships of impact intensity to depth of specific geologic materials is not determinate, since plutonic bodies of mafic composition are not restricted to any depth on earth at all times, and basaltic extrusive expressions of chemical compositions rich in ferromagnessian minerals (noritic and gabbroic rock) are exceedingly common here. This new lunar material seems to be hypabyssal macroscopically, which may account for the reported subjective responses of certain members of the meteoritical community of similarity to shergottites, which are related to extrusive and hypabyssal intrusive activity on mars.

Martin Altmann <altmann at meteorite-martin.de> wrote: Hi Rob,

".. Meteorites have, at least the potential to come from
deeper than the long weathered surface materials
brought back by the Apollo crews. This all makes sense
to me, if it is a confirmed discovery."


You're right Rob,

For example the pairing group around Dho 310-breccias has some spinel,
indicating that those parts of the breccia stem from the deeper lunar crust
(>20km), see here:
http://www.meteorites.ru/menu/publication-e/demidova-ms2003-e.pdf

Or take the fresher granulite NWA 3163/4483, which is suggested to be a
crustal rock, practically not sampled by the Apollo missions:
http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1365.pdf

Best
Martin


-----Urspr?ngliche Nachricht-----
Von: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] Im Auftrag von Rob
McCafferty
Gesendet: Mittwoch, 28. Februar 2007 23:10
An: gipometeorites; meteorite-list at meteoritecentral.com
Betreff: Re: [meteorite-list] NEW LUNAR monzogabbro meteorite looks like
aShergottite

I am not going to claim any authority in the area of
geology but I will claim a good experience of
Anorthosite, a principle constituent of the lunar
surface. The Isle of Harris, the next island down from
me [is actually connected to my island, Lewis, by a
land bridge] has an entire mountain made from the
stuff, despite it's rare nature and I've collected
plenty of it to decorate my garden.
It weathers by ice and abrasion to the same gorgeous
white colour of the genesis rock brought back by the
Apollo 15 crew. This is not surprising since their
rock was weathered on the outside too, but that stone
was impact weathered only.

Inside the rocks from harris they are remarkably
crystaline, quite grey in appearance and U took the
liberty of borrowing a lathe[?] to polish a small
section of a chunk i rather brutally chipped off with
a chisel. Apart from the colour, it looks very like a
piece of SAU008/005, a shergottite.

In all honesty and with hindsight, it does not
surprise me that a lunar meteorite may well look like
a martian one.

Anorthosite I believe, is a plutonic rock and since
most of the white part of the moon is made from it,
the only surpise to me, after thinking about it, is
that one that looks like a shergottite has not been
discovered before.

I suggest that aeons of impacts on the moon do not
leave big enough chunks near the surface to preserve
the structure of the rock and that is why we haven't
seen one before. Having said that, we've only really
been looking for a few years.
Meteorites have, at least the potential to come from
deeper than the long weathered surface materials
brought back by the Apollo crews. This all makes sense
to me, if it is a confirmed discovery.

In a differentiated body the size of the moon and
mars, I think, in retrospect, we should not be
surprised at all.

Obviously, if this turns out to be a hoax, I absolve
myself of all I have said here on the grounds that I
have never heard of monzogabbro before. Gabbro is just
a feldspar with less than 60% or is it 40%[?]
anorthosite. What the frip does monzo mean? I thought
he was a character in the muppet show.

Rob McC
{the man with a million tons of fake moon rock}


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Received on Thu 01 Mar 2007 04:36:33 AM PST