[meteorite-list] a question on fusion crust

[Greg Hupe]

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

>>

> === message truncated ===

>

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