[meteorite-list] a question on fusion crust

From: Greg Hupe <gmhupe_at_meteoritecentral.com>
Date: Thu, 22 Mar 2007 12:56:09 -0400
Message-ID: <068a01c76ca2$fdefee50$c0125c18_at_Gregor>

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)
gmhupe at tampabay.rr.com
www.LunarRock.com
IMCA 3163
====================


----- Original Message -----
From: "Michael Farmer" <meteoriteguy at yahoo.com>
To: "Armando Afonso" <armandoafonso at oniduo.pt>;
<meteorite-list at 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 <armandoafonso at oniduo.pt> 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" <meteoriteguy at yahoo.com>
>> To: "Mr EMan" <mstreman53 at yahoo.com>; "Michael
>> Murray"
>> <mmurray at montrose.net>;
>> <Meteorite-list at 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 <mstreman53 at yahoo.com> 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 <mmurray at montrose.net> 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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Received on Thu 22 Mar 2007 12:56:09 PM PDT