Hi Mike and List,
Even the "soot" is part of the material coming into the atmosphere, altered,
combined or...
Best regards,
Greg
====================
Greg Hupe
The Hupe Collection
NaturesVault (eBay)
[EMAIL PROTECTED]
www.LunarRock.com
IMCA 3163
====================
----- Original Message -----
From: "Michael Farmer" <[EMAIL PROTECTED]>
To: "Armando Afonso" <[EMAIL PROTECTED]>;
<meteorite-list@meteoritecentral.com>
Sent: Thursday, March 22, 2007 12:48 PM
Subject: Re: [meteorite-list] a question on fusion crust
But made from the matrix component. burned material
from the parent body, regardless of how it is
chemically changed, same as the fusion crust on any
meteorite. Take a Eucrite like Stannern for example,
white interior, yet the fusion crust is glossy black.
That is not soot, it is chemically altered matrix.
Nothing more.
Michael Farmer
--- Armando Afonso <[EMAIL PROTECTED]> wrote:
Obviously, it is a diferent material...
The external fusion crust of iron meteorites is
Magnetite, the result of the
combination with the air`s oxygene.
AA
----- Original Message -----
From: "Michael Farmer" <[EMAIL PROTECTED]>
To: "Mr EMan" <[EMAIL PROTECTED]>; "Michael
Murray"
<[EMAIL PROTECTED]>;
<Meteorite-list@meteoritecentral.com>
Sent: Thursday, March 22, 2007 4:14 PM
Subject: Re: [meteorite-list] a question on fusion
crust
> This is simple.
>
> Fusion, the result of material burning at extreme
> temeratures, and crust, the layer on the surface
that
> was not there before re-entry.
> Thus, FUSION CRUST
> It is quite obvious that the surface of a freshly
> fallen iron, with the blue-black coating is a
FUSION
> CRUST.
> It generally can't be "wiped" off. I have pieces
in my
> collection, Bugoslava for example, with a .5 mm
layer
> of blue-black fusion crust, that survived cutting
and
> polishing of the meteorite, so it is not exacly
> "soot". Of course the crust is the same as the
parent
> material, even on stones. How could it be of a
> different material? How could an object, falling
> through the atmosphere, get coated with anything
but
> it's own matrix as it burns? Yes, the silicates
can be
> altered due to heating, while irons tend not to
> chemically alter.
> Elton, I think you are about the only one in the
world
> that thinks fresh fallen iron meteorites do not
have
> fusion crust.
> Michael Farmer
>
> --- Mr EMan <[EMAIL PROTECTED]> wrote:
>
>> The "soot" coating you are talking about is
mostly
>> freshly created magnetite (micro /nano crystals)
>> from
>> the oxidation of iron whilst passing through the
>> incandescent phase. It adheres by magnetism and
can
>> be wiped off with rough handling. There is
probably
>> a
>> carbon component however graphite turns to carbon
>> dioxide upon burning >
>> There are several other terms for the zone
>> associated
>> with "ablation" heating, one of which is in the
>> literature: "zone of thermal alteration". When
there
>> is an oxidation coat
> .
> native elements such as
>> found
>> on sodium or phosphorus it is sometimes called a
>> rind.
>> This is what I favor to describe the coatings on
>> irons--the one before terrestrial oxidation also
>> known
>> as rust.
>>
>> In my view there can be no crust when the
chemical
>> and
>> physical characteristics of the surface do not
>> differ
>> from the donor material. That lets the door open
>> for
>> irons having crust and at least most agree that
it
>> is
>> unlike the fusion crust of stoney meteorites.
>>
>> While at the Smithsonian inspecting the
collection
>> up
>> close and personally, I was advised to use
caution
>> in
>> examining a fresh iron as the coating would rub
off
>> easily. They didn't call it fusion crust but the
>> issue
>> never came up. The point being, not everyone is
in
>> agreement nor is there universal usage.
>>
>> Critical analysis on the assumptions about fusion
>> crust on irons would likely lead to a more
>> descriptive
>> table of composition and relate that to the
>> metallurgy
>> and chemical composition of the meteorite itself.
In
>> fact I believe research on crustal petrology
would
>> be
>> reveling for all types of meteorites. I yet
wonder
>> why
>> some lunarites have a brown bubbly crust. The
crust
>> of
>> a iron meteorite on Mars will be different from
one
>> here and I'd like to know what to expect and why.
>>
>> Intuitively, I know there would be rare minerals
>> such
>> as nickel oxides,nitrates, phosphates perhaps
even
>> a
>> sulphide and yes even O3 and O4 silicates.
However
>> current wisdom is that crust is crust ego no
>> research
>> needs to be contemplated-NOT.
>>
>> Some of the oft quoted god status experts who
write
>> of
>> fusion crust on irons monitor this list and have
>> remained curiously silent on the topic. I hope
this
>> topic is thought provoking for all parties.
>>
>> I suppose that the use of the term "fusion crust"
>> universally with respect to irons is acceptable
if
>> one
>> doesn't have a need for technical accuracy. One
>> thing
>> yet to be refuted here on the list is that the
>> "crust"
>> on irons is not composed of "glass".
>>
>> Elton
>>
>> --- Michael Murray <[EMAIL PROTECTED]> wrote:
>>
>> > Hi List,
>> > Are you ready for a dumb question! Here
goes...
>> Is
>> > there a more definitive description of the
>> blackened outer layer on the surface of iron
>> meteorites than simply referring to it as "fusion
>> crust"? From what I can gather looking at
different
>> pictures of stonys, they seem to have a glassy
or
>> melted layer of the material of the stone. I can
>> see
>> that being a 'crust'. On at least some irons,
there
>> is a coating but it doesn't appear glassy, just
>> blackened. I'm guessing that that coating is
>> partially resulting from burning of the gases in
the
>> atmosphere? If it is a 'crust', it is not much
of
>> one. It looks
>> like a very thin coating of soot that is adhered
to
>> the stone, although more durable than soot.
This
>> is
>> probably one of those dumb questions that the
>> Collection of Wisdom would answer.
>>
>> The stone in this picture has the blackened
layer
>> I'm referring to:
>>
>
<http://i127.photobucket.com/albums/p124/mmurray_02/IMG_0319.jpg>
>> Michael Murray
>> ______________________________________________
>> Meteorite-list mailing list
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