[meteorite-list] Lawrencite-like oozing from an H6 Impact Melt Breccia

From: Mal Bishop <magbish3_at_meteoritecentral.com>
Date: Thu Apr 22 10:04:50 2004
Message-ID: <5.1.0.14.2.20020521172139.00b68fe8_at_mail.lig.bellsouth.net>

Hi List,

First of all, "Hi", to everyone on the list new and old, and I don't mean
age wise! :-)

I'll get to my question in a minute, but I wanted to make an observation first.

I've been on and off of the list for 3 or 4 years, but lately (last year or
so) mostly
a lurker. Back in the earlier days there were some on this list more
interested
in stirring up the "mix" so-to-speak than carry on any meaningful dialogue,
transfer of knowledge, or just plain enrich the passion of others on the
list that really
wanted to "talk" meteorites! After a few unpleasant run-ins and realizing
that it
appeared the list was really nothing much more than an on-line market for
dealers
and collectors wishing to trade/sell meteorites, and most of the remaining
threads
involved the aforementioned malarkey, I just kind of slipped into the
background and hung
around waiting for that relatively rare and interesting tidbit of info
actually concerning
meteorites! There were a handful of regular contributors, and experts that
came
through back then just as they still do today, and I think most of you know
the individuals
I'm referring to!

The reason for the above statement is to my great pleasure and enjoyment,
this list has changed for the better and is getting better all of the time.
I think there were many members, in fact I know there were some members for
they emailed me privately with the same concerns, whom would not join in
out of
fear of being ridiculed and harassed. Well, it seems as if it is all water
under the bridge now!

Now to my question... I recently purchased a beautifully prepared part
slice of Dhofar 010
which is an H6 impact melt breccia. It shows a very dark black melt (the
matrix material)
surrounding the lighter brown unmelted clasts sparkling with tiny bits of
metal. I've had it now for almost a month.
The past week, week and a half, I noticed that it has dark, brown, greenish
looking droplets of moisture
oozing out on the back unpolished side and a couple of droplets on the
front highly polished side. Right away I thought Lawrencite
and Nantans not to mention a couple of other irons and Pallasites, but this
is an ordinary chondrite (H6)
and I just haven't heard of this problem with chondrites. If they
[chondrites] can have the "disease" as well
as irons then I'm just ignorant of it! Even under just a 10x magnifier, it
looks like the "cancer" of irons as,
I think, Richard Norton put it. I have or had many different types of
chondrites, and many of course, are or were
ordinary ones from LL's to H's an 3's to 6's, but I never saw this before
-- I haven't read or heard anyone else speak of this either!
When I wipe the moisture off, it will have returned again within the next
day or two.

Another interesting fact is that the oozing appears to be coming from the
melt (matrix) surrounding the
clasts (breccia) on the back side and not from any of the clasts themselves
that I can tell. Of course, I could
be very wrong for I'm by no means an expert -- just learning all the time.
The polished front side seems to really have only one area and it is a tiny
clast, but this clast has a couple
of small holes or pores -- therefore, I suspect it's just bleed through
from the back side where the melt happens
to line up from behind that particular clast!

Believe it or not, in the past with a couple of Nantans that after cutting
started oozing very badly, I'd soak
them for days, weeks, and even months in anhydrous isopropanol (isopropyl
alcohol). When the solution
began looking brown or somewhat less than perfectly clear (to my subjective
eye) I would exchange it
for pure alcohol again. I would do this probably 2,3, or 4 times depending
on the tenacity of the iron involved --
maybe more. This stuff I use is 99.995% water free and it WILL dry out
whatever you have in mind -- including your fingers! ;-)
But the point is, after whatever period of time it took and the particular
Nantan piece involved, I eventually
got the blasted thing to stop oozing. One I'm soaking right now has been
in solution for nearly one year.
I take it out occasionally and just let it sit for several days to see if
it begins oozing again, so far, so good!
My next step will be to let it sit in the display case for several weeks
and keep an eye on it. If all goes well
I may or may not clearcoat it.

I said all of that just to point out nothing, I guess really, with my
question at hand other than if nothing else the alcohol
bath should do the same trick if it is Lawrencite or something
related. Like I said though, I'm far from any expert with
preparing, conditioning, and maintaining irons or any meteorite (or rock)
for that matter, but I try a little, learn a little,
read a little, and learn a little more!

SORRY for the lengthy email, but I'm just curious, concerned, and ready to
learn more from this distinguished
and informed list of members!

Anybody have any answers, similar occurrences, or whatever?

Regards,
Mal
Received on Tue 21 May 2002 08:10:08 PM PDT