[meteorite-list] Clarification.. Was Fusion Crust on Irons

[info at niger-meteorite-recon.de]

Elton,
 Could you please name the significant source you refer to by presuming that the
term fusion crust is only valid when describing crusts made up of glass/silicate
components?
 
I'm asking because the discussion so far did not provide any intelligent reason
why this should make any sense at all. Perhaps it would be a good idea to start
from there.
 
Svend
 
 

www.meteorite-recon.com

 
MEM <mstreman53 at yahoo.com> hat am 20. November 2009 um 06:08 geschrieben:


> Again Yahoo is near comatose and I am not getting all the posts.

> 

> We are going to eventually see a predominately iron meteorite which is going

> to have a legitimate "fusion crust" (meeting the definition).

> 

> When I said "non -silicate" bearing I meant insignificant silicate content and

> was trying to establish and end point for a series, mineralogically and

> metaphorically speaking--otherwise... as has happened here time and time

> again, people start throwing in exceptions and progress stops.  (e.g. Campo

> was non-silicate bearing until someone found a silicated batch). 

> 

> Discussion is complicated by the lack of adequate definitions/ descriptions.

> They abound especially in a rare commodity. For another vexing example of

> undefined: how many atoms of copper, gold or lead need be in a "glob" in a

> meteorite to legitimately say that a meteorite has native Cu, Au, or PB? Every

> meteorite has an C,A,P atom so or per billion but where do we draw the line on

> declaring it?

> 

> 

> So you all know where I am going with this:  I would like to see a new list of

> terms used in our field which ensures we are discussing the same thing/feature

> observed on multiple meteorites.  I think many agree that as the term fusion

> crust is now defined and how it is actually used to refer to every eventual

> possible appearance-- even on rusty iron shale( yes someone has offered

> "fusion crusted" iron shale before) and fusion crusted paleo meteorites-- are

> very different things and that we need a better convention of what is and or

> is not the result of flight and how it relates to surface features in general

> on all types of meteorites.  Suprisingly, very little science has been focused

> on the formation and features of "fusion crust" especially compared to the

> internal content. Even less effort has been directed are promoting operational

> terms to describe what is observed on different surfaces.

> 

> Personal business has taken me far from the list for several weeks so if I

> haven't addressed your message please feel free to resend. I may not be active

> on the beloved list but I am getting some lab work done and hope to announce

> some really neat things next year.

> 

> Happy Thanksgiving for those that celebrate the season...  Hope to be back

> before Christmas and BTW what dates are the Las Vegas(ahem)Gem and Mineral

> Show?

> 

> Elton

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