[meteorite-list] Question for type collectors

From: Galactic Stone & Ironworks <meteoritemike_at_meteoritecentral.com>
Date: Wed, 15 Apr 2009 11:22:04 -0500
Message-ID: <e51421550904150922n6cc651dcqb41641bd1029acbe_at_mail.gmail.com>

Hi Jeff and Michael,

Thank you for the input. I think what I will do is subdivide my type
list into two arbitrary categories - irons and everything else. So I
will treat irons seperately. I will maintain my "petrologic type"
count for stony, stony-iron, and everything else that doesn't fall
under "irons".

I asked all of this because I like to have a record of the various
aspects of my collection - just in case someone asks me questions like
- "How many lunars do you have?" or "How many types do you have?", or
"How many witnessed falls?" , etc.

Plus I am a statistics geek and I like to have everything in my
collection accounted for and broken down to the Nth degree. ;)

I have yet to break down my collection by country - that will come
tonight. I need to do it now while my collection size is still
manageable.

Best regards,

MikeG


Here are some of the revised stats now -

29 witnessed falls, 55 finds - 84 total localities

29 witnessed falls
14 hammer falls (3 hammer stones)

42 petrologic types
  5 iron types - IAB-MG, IIIAB, IVA, IAB-ung, unclassified (Las Palmas)

7 continents
18 USA falls and finds
10 US states - Alabama, Arizona, Connecticut, Georgia, Illinois, Iowa,
Kansas, Louisiana, New York, Texas
28 NWA finds

7 planetaries (3 Lunars, 4 Martians, 8 Vestans)

47 specimens <1 gram
27 specimens 1-9 grams
12 specimens 10-99 grams
2 specimens >100 grams


.................................................................

On 4/15/09, Jeff Grossman <jgrossman at usgs.gov> wrote:
> "Petrologic type" is really a term that only applies to chondrites. It
> was popularized in the classic paper:
>
> VAN SCHMUS W. R. and WOOD J. A. (1967) A chemical-petrologic
> classification for the chondritic meteorites. Geochimica et Cosmochimica
> Acta 31, 747-765
>
> The term was meant to convey a sense of the degree of equilibration of
> chondrites.
>
> In the old days, there were only 6 defined petrologic types (1-6),
> making it easy on a collector or museum wishing to establish a reference
> collection. But now, the scale is interpreted more continuously, with
> nearly 30 subdivisions appearing in the literature in one place or
> another (1, 2.0-2.9, 3.01-3.05, 3.10, 3.15, 3.2-2.9, 4, 5, 6), as well
> as transitional types like 1/2, 3.6/3.7 or 4/5, and breccia mixtures
> like 4-6..
>
> As for nonchondritic meteorites, petrologic type is undefined. For some
> of these, there are groups, like the groups of irons you mention, which
> are analogous to the groups of chondrites (H, L, LL, R, CV, etc.). Some
> of these are themselves subdivided, as is the IAB complex. For other
> achondrites, like mesosiderites, there aren't really groups defined, but
> they have been subdivided into petrographic classes and metamorphic
> grades, with designations like "B1" to show this. HEDs and ureilites
> are really messy.
>
> Textural terms, like the iron structural types you mention, or terms
> like "polymict," "brecciated," etc., are not really classification terms
> (in general). These are mostly descriptive terms. Use these to
> subdivide a collection with caution, as they may not be applied
> uniformly to all meteorites by all researchers.
>
> Jeff
>
>
>
> Galactic Stone & Ironworks wrote:
>> Hi folks!
>>
>> I am not a type collector per-se, but I like to keep track of how many
>> different petrologic types I have in my collection.
>>
>> I have a silly question about type collecting -
>>
>> Do type collectors consider each type of iron a seperate petrologic
>> type? For example, are all octahedrites considered 1 type? Or is it
>> different types for "coarsest", "coarse", "medium", "fine", etc?
>>
>> Right now I have 42 petrologic types - counting ALL irons as only one
>> type. Should I go through my collection and correct that count to
>> reflect the different types - IIAB, IAB, IVA, etc?
>>
>> Thanks in advance!
>>
>> MikeG
>>
>>
>>
>
>
> --
> Dr. Jeffrey N. Grossman phone: (703) 648-6184
> US Geological Survey fax: (703) 648-6383
> 954 National Center
> Reston, VA 20192, USA
>
>
>

-- 
.........................................................
Michael Gilmer (Louisiana, USA)
Member of the Meteoritical Society.
Member of the Bayou Region Stargazers Network.
Websites - http://www.galactic-stone.com and http://www.glassthrower.com
..........................................................

Received on Wed 15 Apr 2009 12:22:04 PM PDT