[meteorite-list] The Perils of Type Collecting - A Guide

From: Richard Kowalski <*damoclid_at_meteoritecentral.com*> Date: Wed, 3 Mar 2010 15:38:22 -0800 (PST) Message-ID: <396037.71872.qm_at_web113618.mail.gq1.yahoo.com> · damoclid_at_meteoritecentral.com

--
Richard Kowalski
Full Moon Photography
IMCA #1081
--- On Wed, 3/3/10, Galactic Stone & Ironworks <meteoritemike at gmail.com> wrote:
> From: Galactic Stone & Ironworks <meteoritemike at gmail.com>
> Subject: [meteorite-list] The Perils of Type Collecting - A Guide
> To: "Meteorite List" <meteorite-list at meteoritecentral.com>
> Date: Wednesday, March 3, 2010, 4:18 PM
> Greetings Listees and fellow
> collectors,
> 
> To the veteran collector, there will be little of interest
> in this
> post.? This post is directed at the silent newbie or
> beginner lurkers
> who are sorting through this List and trying to find their
> way around
> the world of collecting meteorites.
> 
> Many new collectors often want one of each type of
> meteorite.? Many
> veteran collectors abandon this pursuit because the task is
> quite
> daunting.???So when you hear talk about
> "type collecting", or building
> a "type collection", what exactly does that mean?? I
> hope the
> following brief article will answer those questions, or at
> least point
> the reader in the right general direction.? Note, I
> gleaned much of
> this type information from David Weir's authoritative
> website
> "Meteorite Studies" and from the Meteoritical
> Bulletin.? I do not
> claim that this list is 100% complete or without error, so
> if the
> reader spots an error or omission, please reply and correct
> it.
> 
> -----
> 
> The Perils of Type Collecting ........
> 
> I started out collecting meteorites with a small sample of
> NWA 4293 -
> an ordinary high iron chondrite of the H6 type. It was
> about the size
> of a dog-food kibble and it looked like one. But I was
> instantly
> hooked, and I wanted to have one each of the different
> types of
> meteorite. This is known as "type collecting" or building a
> "type
> collection".
> 
> The danger of type collecting (besides the damage to one's
> checking
> account) is that the various petrologic types are
> subdivided into
> various grades according to metamorphism.
> 
> For example, take the H chondrite group that my NWA 4293
> sample belonged to.
> 
> There are H3 chondrites, H4 chondrites, H5 chondrites, and
> H6
> chondrites. Did I really need one each of these subtypes?
> Well, it
> depends on how deep a collector wants to go into the rabbit
> hole.
> There are distinct differences between the various H types.
> The number
> attached to each is more than just a simple weathering
> grade or shock
> grade. It represents a progession in the H-chondrite family
> from least
> altered to most altered. H3 chondrites are loaded with
> chondrules, H4
> have some chondrules, H5 has few chondrules, and H6 has
> virtually no
> visible chondrules. A new grade of H7 has been added as
> well. So, a
> collector could simply have a single Hx chondrite and say
> that the
> H-chondrites are represented. Or, the collector could have
> one each of
> the different subtypes from 3 to 7.
> 
> Another peril is the changing of nomenclature. For example,
> the
> K-subgroup of carbonaceous chondrites was only recognized
> and
> designated in 1990. Up until then, Karoonda was considered
> a CV4
> meteorite of the Vigarano family. Now Karoonda is
> recognized as
> distinctly different type of carbonaceous chondrite, so it
> was made
> into it's own group. Now we have CK4, CK5, and CK6
> meteorites - all
> represent a progression in metamorphism and have visible
> (and
> chemical) differences from other grades. There are standout
> members of
> each subgroup, so where does one draw the line? Should the
> collector
> acquire a sample of Karoonda and be done with it? Or should
> the
> collector go out and track down CK4, CK5 and CK6
> meteorites? Again, it
> depends on how extensive and exhaustive a collector wants
> to be with
> their type collection. Budget will also play a role as
> well, because
> an exhaustive type collection is a daunting project.
> 
> Lastly, one must consider the ungrouped meteorites. These
> are oddball
> meteorites that do not neatly fit into the pre-existing
> meteorite
> types. There are ungrouped chondrites, ungrouped
> achondrites, and
> ungrouped irons. No type collection can overlook these
> meteorites
> because some of them are types unto themselves with unique
> qualities.
> 
> For those who want to build a definitive and complete type
> collection,
> here is a list of every known type and subtype of
> meteorite. This list
> was culled from other sources, including David Weir's
> authoritative
> "Meteorite Studies" website linked at the end of this
> post.
> 
> Carbonaceous Chondrites :
> 
> CI (Ivuna)
> CM1 (Murchison)
> CM2 (subdivided into CM2.0 to CM2.6)
> CM3
> CO3 (Ornans) (subdivided into CO3.03 to CO3.7)
> CV (Vigarano) (also CV2 and CV3)
> CK (Karoonda) (CK4, CK5, CK6)
> CR (Renazzo) (CR1, CR2, CR3)
> CB (Bencubbin)
> CH
> CR ungrouped
> C4 ungrouped
> C ungrouped (Tagish Lake, others)
> 
> 
> Ordinary Chondrites :
> 
> Rumuruti R3 (subdivided into R3.5-6 to R3.9)
> R4
> R5
> R6
> 
> LL (subdivided into LL3.0 to LL3.9)
> LL4
> LL5
> LL5/6
> LL6
> LL6/7
> LL7
> LL impact melt
> 
> LL transitional (L/LL3 to L/LL6)
> L (subdivided into L3.0 to L3.9)
> L4
> L5
> L6
> L6/7
> L7
> L impact melt
> 
> H/L transitional (H/L3 to H/L6 IMB, H/L3.6 to H/L3-4)
> H (subdivided into H3.0 to H3.9)
> H4
> H5
> H6
> H7
> H impact melt
> ungrouped ordinary chondrites
> 
> 
> Enstatite Chondrites :
> 
> EL (EL3 to EL7)
> EL impact melt
> EH/L
> EH (EH3 to EH7)
> EH impact melt
> ungrouped enstatite chondrites
> 
> K (Kakangari)
> 
> Meta-chondrites (M-CV, M-CR, M-H, M-LL)
> 
> 
> Primitive Chondrites :
> 
> Acapulcoite
> Lodranite
> Winonaites
> ungrouped primitive chondrites
> 
> 
> Achondrites :
> 
> Howardite (subdivided into fragmental breccia and regolith
> breccia)
> Eucrite (monomict and polymict with each having
> subclasses)
> Diogenite (monomict and polymict)
> Olivine Diogenite
> Dunite
> Ureilite (monomict and polymict)
> 
> 
> Martian achondrites :
> 
> Shergottite
> Pyroxene-phyric basaltic shergottite
> Olivine-phyric basaltic shergottite
> Olivine-orthopyroxene-phyric basaltic shergottite
> Pyroxene-peridotitic (Wehrlitic) shergottite
> Lherzolitic shergottite
> Diabasic shergottite
> 
> Nakhlite
> Chassignite
> Orthopyroxenite (ALH 84001)
> 
> 
> Lunar Achondrites :
> 
> Feldspathic breccias
> Regolith breccia
> Fragmental breccia
> Impact melt breccia
> Granulitic breccia
> Mafic-rich
> Thorium-rich
> KREEP-rich
> 
> Mingled Breccia
> Mare Basalt
> 
> 
> Other Achondrites :
> 
> Angrites (Plutonic and Basaltic)
> Brachinite
> Aubrite
> ungrouped achondrites (Ibitira, Pasamonte, etc)
> 
> 
> Stony-Irons :
> 
> Mesosiderites (1A,1B,2A,2B,2C,3A,3B,4A,4B)
> ungrouped mesosiderites
> 
> Pallasites (Main Group, Eagle Station group, Pyroxene
> group)
> Pallasite-am (anomalous, PMG-am, PMG-as)
> ungrouped pallasites
> 
> 
> Iron meteorites :
> 
> Note, iron meteorites are a can of worms. I will only focus
> on the
> main chemical groups, and not the various grouplets and
> sub-types of
> each main chemical group.? Also note that many of
> these types include
> silicated varities.? Listing all of the known
> sub-types of irons would
> require a LONG list resembling a flow-chart.
> 
> IAB
> IC
> IIAB
> IIC
> IID
> IIE
> IIF
> IIG
> IIIAB
> IIIE
> IIIF
> IVA
> IVB
> ungrouped irons
> 
> I think that is all of them - as currently recognized by
> the
> Meteoritical Society Nomenclature Committee. If anyone can
> think of
> some I missed, please add them to this list.
> 
> David Weir's Meteorite Studies website - http://www.meteoritestudies.com/
> 
> Best regards and happy collecting!
> 
> MikeG
> 
> 
> -- 
> ------------------------------------------------------------
> Mike Gilmer - Galactic Stone & Ironworks Meteorites
> http://www.galactic-stone.com
> http://www.facebook.com/galacticstone
> ------------------------------------------------------------
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