Systematics: Achondrites, Primitive Achondrites, Irons & Stony Irons Classification

PART I: CHONDRITES, METACHONDRITES
PART III: MARTIAN METEORITES—GEOCHEMICAL CLASSIFICATION
PART IV: DIOGENITES—IUGS TAXONOMY
PART V: ENSTATITE CHONDRITES—SUBGROUP CLASSIFICATION

PRIMITIVE ACHONDRITES

INCIPIENT DIFFERENTIATIONA process by which a generally homogeneous chondritic body containing mostly metal, silicates and sulfides will melt and form distinct (differentiated) layers of different densities.   When the melting process continues for a long enough period of time, the once chondritic body will re-partition into layers of different composition including
(including restites from very low degree partial melts)

ACAPULCOITE–LODRANITERare type of primitive achondrite named after the Lodran meteorite that fell in Pakistan in 1868. Initially, lodranites were grouped with the stony-iron meteorites because they contain silicates (olivine, orthopyroxene, and minor plagioclase) and Fe-Ni metal in nearly equal proportions. However, since discovery of the closely related acapulcoite group, lodranites CLAN (5 metamorphicRocks that have recrystallized in a solid state due to changes in temperature, pressure, and chemical environment. subgroups, after Floss, 2000; Patzer et al., 2003)

1. Primitive AcapulcoitesPrimitive achondrite that belongs to a small group named after the Acapulco meteorite that was observed to fall in Mexico in 1976. Acapulcoites are made mostly of fine-grained olivine (Fo3-14), orthopyroxene(En86-97), Ca-rich pyroxene (En51Wo44), plagioclase (An12-31), Ni-Fe metal, and troilite. They are transitional between primordial chondritic matter and more differentiated [Se >12–13 ppm] (e.g. ALHA77081, GRA 98028 [‘A chondrite’, highly primitive {~6 vol% chondrules}], GRV 020043 [‘A chondrite’, highly primitive {type 4, ~62 vol% chondrulesRoughly spherical aggregate of coarse crystals formed from the rapid cooling and solidification of a melt at  ~1400 ° C. Large numbers of chondrules are found in all chondrites except for the CI group of carbonaceous chondrites. Chondrules are typically 0.5-2 mm in diameter and are usually composed of olivine; photo credit: Li et al., 2018}], Monument Draw [‘A chondrite’], Y-74063 [‘A chondrite’])

2. Typical Acapulcoites [Se ~5–12 ppm] (e.g. Acapulco, ALH 78230, ALHA81261, Dho 125 and pairings, Dho 290, Dho 312, FRO 95029, NWA 1617, NWA 2656 and pairings, NWA 2775, TIL 99002)

3. Transitional Acapulcoites [Se <5 ppm] (e.g. ALHA81187, EET 84302, FRO 93001, GRA 95209, LEW 86220, MAC 041193, NWA 2627)

4. Lodranites [K <200 ppmParts per million (106)., Grain size 500+ µm] (e.g. GRA 95209, Lodran, MAC 88177, NWA 468 [anom, metal-rich], NWA 2235, NWA 3341, NWA 4448, NWA 4478, NWA 4529, NWA 4663, NWA 4833, NWA 4875 [possibly paired with NWA 4478], Willcox Playa 010 [highly reduced])

5. Enriched Acapulcoites [addition of feldspar-rich melt] (e.g. FRO 93001, LEW 86220)

BRACHINITE CLAN (2 divisions, after Goodrich et al., 2017)

1. Brachinites (e.g. ALH 84025, Brachina [most primitive], Eagles Nest, EET 99402/7, Hughes 026 [syn: Australia 1], NWA 3151, NWA 4969 and pairings, NWA 4876, NWA 5191 [possibly paired with NWA 3151], NWA 5471, NWA 6308, Reid 013 [a portion under the synonyms NovaStar that, over a period of a few days, becomes 103 to 104 times brighter than it was previously. Novae are observed about 10-15 times per year in the Milky Way. 003 and Window Butte], Reid 027)

2. Brachinite-like (e.g. Divnoe, MIL 090206 and pairings, MIL 090340, NWA 595, NWA 1500, NWA 4042, NWA 6112, Zag (b))

WINONAITES (3 metamorphic subgroups; adapted from Floss, 2000 and Patzer et al., 2003)

1. Primitive Winonaites (e.g. Dhofar 1222 [‘W chondrite’ {~4 vol% chondrules}], Mount Morris [‘W chondrite’], NWA 516, NWA 8614, Pontlyfni [‘W chondrite’])

2. Typical Winonaites (e.g. Fortuna, HaH 193, NWA 1457, Winona)

3. Evolved Winonaites (e.g. NWA 2993, Tierra Blanca)

UREILITES (2 divisions)

1. Monomict/Unbrecciated (4 mineralogical types)

A. Olivine-Pigeonite, mantleMain silicate-rich zone within a planet between the crust and metallic core. The mantle accounts for 82% of Earth's volume and is composed of silicate minerals rich in Mg. The temperature of the mantle can be as high as 3,700 °C. Heat generated in the core causes convection currents in residue (e.g. DaG 084, DaG 868, Dhofar 979, Haverö, Kenna, Novo Urei, NWA 2624, NWA 7630 [dunitic]; intermediate: e.g. Hajmah (a))

B. Olivine–OrthopyroxeneOrthorhombic, low-Ca pyroxene common in chondrites. Its compositional range runs from all Mg-rich enstatite, MgSiO3 to Fe-rich ferrosilite, FeSiO3. These end-members form an almost complete solid solution where Mg2+ substitutes for Fe2+ up to about 90 mol. % and Ca substitutes no more than ~5 mol. % (higher Ca2+ contents occur, mantle residue (e.g. EET 87511 and pairings, EET 87517, LEW 85440 and pairings, MET 01085, NWA 11511 [anom, opx-rich, sodic plag.-bearing], Y-74659, Y-791538)

C. Olivine–AugiteHigh-Ca clinopyroxene, (Ca,Mg,Fe)SiO3, that occurs in many igneous rocks, particularly those of basaltic composition. In order to be considered augite, the clinopyroxene must contain 20 to 45 mol % of calcium (Wo20 - 45). An important and unique Martian meteorite is NWA 8159, that has been classified as an augite basalt., mantle cumulateIgneous rock composed of crystals that have grown and accumulated (often by gravitational settling) in a cooling magma chamber. or paracumulate (2 categories)

i. Plagioclase-free (e.g. Almahata Sitta #15, ALH 82106 and pairings, Calama 001, EET 96293 and pairings, FRO 90054 and pairings, HaH 064, Hughes 009, LEW 88774, META78008, NWA 3222, Ramlat as Sahmah 530 [photo courtesy of Marcin Cimala], Y-74130)

ii. Plagioclase-bearing (e.g. AhS MS-MU-012)

D. Trachyandesite (e.g. AhS MS-MU-011, AhS MS-MU-035)

2. Polymict (2 mineralogical types)

A. Shallow regolithMixture of unconsolidated rocky fragments, soil, dust and other fine granular particles blanketing the surface of a body lacking an atmosphere. Regolith is the product of "gardening" by repeated meteorite impacts, and thermal processes (such as repeated heating and cooling cycles).   fragmental brecciaWork in Progress ... A rock that is a mechanical mixture of different minerals and/or rock fragments (clasts). A breccia may also be distinguished by the origin of its clasts: (monomict breccia: monogenetic or monolithologic, and polymict breccia: polygenetic or polylithologic). The proportions of these fragments within the unbrecciated material (e.g. Almahata Sitta)

B. Deep regolith fragmental breccia (e.g. DaG 319 and pairings, EET 83309, Nilpena, North Haig, Reid 016)

ENSTATITES (Pilski et al., 2011) (e.g. Zakłodzie [or MR/IMB])

SILICATEThe most abundant group of minerals in Earth's crust, the structure of silicates are dominated by the silica tetrahedron, SiO44-, with metal ions occurring between tetrahedra). The mesodesmic bonds of the silicon tetrahedron allow extensive polymerization and silicates are classified according to the amount of linking that occurs between the INCLUSIONS IN IRONS (Includes silicates from the IAB complex (e.g. Caddo County, Four Corners, Landes), and from groups IIE (e.g. Netshaëvo, Techado, Watson) and IVA (e.g. São João Nepumuceno, Steinbach)

UNGROUPEDModifying term used to describe meteorites that are mineralogically and/or chemically unique and defy classification into the group or sub-group they most closely resemble. Some examples include Ungrouped Achondrite (achondrite-ung), Ungrouped Chondrite (chondrite-ung), Ungrouped Iron (iron-ung), and Ungrouped Carbonaceous (C-ung). PACS (e.g. Dhofar 500, NWA 7312 [CR-like; abstract], NWA 11042 [L-like; abstract 1, 2; cut face photo courtesy of Abdelhadi Aithiba], QUE 94204, Sah 03500, Tafassasset [CR-like])

ACHONDRITES

VESTAN SUITE

HOWARDITES (2 subdivisions)

1. Fragmental Breccia (e.g. Luotolax, Old Homestead 001, NWA 1182, NWA 1282~NWA 1664~NWA 1769)

2. Regolith Breccia (e.g. Bholghati, Bununu, EET 87513, GRO 95535, GRO 95602, Jodzie, Kapoeta, LEW 85313, Lohawat, Malvern, MET 00423)

EUCRITESMost common type of achondrite meteorite and a member of the HED group. Eucrites are basalts composed primarily of pigeonite and anorthite (An60-98). Eucrites have been placed into three subgroups based on mineralogical and chemical differences. • Non-cumulate eucrites represent the upper crust that solidified on a magma ocean after (2 subdivisions)

1. Monomict or genomict breccia (2 categories)

A. Gabbroic, Cumulate (e.g. Binda [unbr], Moore Co., NWA 1836, NWA 1925, NWA 11729 [anom, highly ferroan; abstract], SaU 493 [anom, hematite-bearing], Serra de Magé, Talampaya, Vissannapeta)

B. Basaltic, Non-cumulate (3 series; Yamaguchi et al., 2009)

i. Main Group–Nuevo Laredo Trend (e.g. Camel Donga, Igdi, Lakangaon, Nuevo Laredo, NWA 999, NWA 3152, Sah 02501, Sioux County)

ii. Stannern Trend (e.g. Stannern, Bouvante, LEW 88010, NWA 4523, PCA 82501)

iii. Residual (e.g. A-87272, Agoult, DaG 945, NWA 2362)

2. Polymict, <10% magnesian orthopyroxeniteA rock composed primarily of orthopyroxene. Non-terrestrial orthopyoxenites include diogenites and a single martian meteorite, ALH 84001, that was found in the Allan Hills region of Antarctica in 1984. ALH 84001 is a cumulate rock consisting of 97% coarse-grained, Mg-rich orthopyroxene, with small amounts of plagioclase, chromite, and carbonate. It (e.g. Dho 007, Millbillillie [unbr], NWA 10674 [anom], Smara, Padvarninkai, PCA 91006)

DIOGENITESDiogenites belong to the evolved achondrite HED group that also includes howardites and eucrites. They are named after the Greek philosopher Diogenes of Apollonia, of the 5th century BCE, who was the first to suggest that meteorites come from outer space (a realization forgotten for over 2,000 years). They are ultramaficTerm used for silicate minerals with cations predominantly Mg and/or Fe. Mafic minerals are dominated by plagioclase and pyroxene, and also contain smaller amounts of olivine. composition—olivine+orthopyroxene ≥90 vol% (7 mineralogical types [IUGS])

1. Orthopyroxenitic (≥90 vol% opx) (e.g. Bilanga, Dhofar 778 [anom], Johnstown, LAP 02216, LEW 88679, MET 00424, NWA 1821, NWA 3106, NWA 3329, QUE 99050, Tatahouine)

2. Olivine–Orthopyroxenitic (opx + 10–40 vol% olv) (e.g. ALHA77256, GRA 98108, LEW 88679, NWA 5312, NWA 5405)

3. Harzburgitic (>40 vol% olv) (e.g. ALHA77256, EETA79002, GRA 98108, LAP 03979, NWA 1459, 1877 and pairings, NWA 4223, NWA 5480, NWA 6157, NWA 7370)

4. Dunitic (≥90 vol% olv) (e.g. MIL 03443, NWA 2968)

5. Noritic (opx + <5 vol% olv + >10 vol% plg) (e.g. NWA 5315, NWA 6928)

6. Polymict (dun ± harz ± opx ± euc (<10 vol%) (e.g. ALH 85015, LEW 88008, NWA 1239, NWA 1648, NWA 4473, NWA 6945 [w/ noritic clasts])

7. Genomict (all clasts fractionally related) (e.g. EETA79002)

TRANSITIONAL diogenites/magnesian cumulate eucrites (e.g. MIL 07003, QUE 93009, Yamato Type B diogenites)

MARTIAN SUITE Petrological and Mineralogical Classification (7 subdivisions)

1.Basaltic (6 categories)

A. Pyroxene-phyric basaltBasalt is the most common extrusive igneous rock on the terrestrial planets. For example, more than 90% of all volcanic rock on Earth is basalt. The term basalt is applied to most low viscosity dark silicate lavas, regardless of composition. Basalt is a mafic, extrusive and fine grained igneous rock (e.g. Dho 378, EETA79001B, Los Angeles, NWA 480/1460 [diabase], NWA 1669, NWA 3171, QUE 94201, Shergotty, Zagami)

B. Olivine-phyric basalt (e.g. Dho 019, EETA79001A, NWA 1068 and pairings, Y-980459 [ol-websterite], NWA 4468, NWA 5789, NWA 6234, NWA 10170, SaU 005 and pairings, Tissint)

C. Olivine–orthopyroxene-phyric basalt (e.g. DaG 476 and pairings, NWA 1195, NWA 2046, NWA 2626)

D. Olivine–plagioclase-phyric basalt (e.g. NWA 7635 [photo; poss. launch paired with NWA 8159])

E. Pigeonite-phyric basalt (e.g. NWA 10414)

F. Augite-rich basalt (e.g. NWA 8159 [poss. launch paired with NWA 7635])

2. Gabbroic/Microgabbroic (e.g. NWA 7320, NWA 8637, NWA 10567, NWA 10761, NWA 11300, NWA 11509)

3. Poikilitic (formerly lherzolitic, bimodal gabbroic intrusiveRefers to igneous rocks that crystallized underground.; 2 categories)

A. Pyroxene-oikocrystic (e.g. ALHA77005, LEW 88516, NWA 1950, NWA 4797, NWA 7397, NWA 10961 [photo courtesy of Ben Hoefnagels], RBT 04261/2, Y-793605, Y-984028 [reg. brec.])

B. Plagioclase–olivine–clinopyroxenite (e.g. NWA 2646)

∗See alternative Geochemical Classification Schemes for the martian basaltic, gabbroic, and poikilitic meteorites based on elemental, isotopic, and other trends.

4. Orthopyroxenite (e.g. ALH 84001)

5. Olivine–clinopyroxenite (e.g. Caleta el Cobre 022, Governador Valadares, Lafayette, MIL 03346 and pairings, Nakhla, NWA 817, NWA 998, NWA 5790/6148, NWA 10153 and pairings, Y-000593/749/802)

6. Polymict Regolith Breccia (e.g. NWA 7034/7533 and pairings [alkali-rich])

7. Dunite (e.g. Chassigny, NWA 2737, NWA 8694)

LUNAR SUITE after List of Lunar Meteorites
Randy L. Korotev—Washington University in St. Louis

Sampling the Feldspathic Highlands Terrane, Procellarum KREEPLunar igneous rock rich in potassium (K), rare-earth elements (REE), phosphorus (P), thorium, and other incompatible elements. These elements are not incorporated into common rock-forming minerals during magma crystallization, and become enriched in the residual magma and the rocks that ultimately crystallize from it. Terrane, South Pole-Aitken Terrane, and associated mariaBroad low plains surrounded by basin-forming mountains, originally thought to be a sea (pl. maria). This term is applied to the basalt-filled impact basins common on the face of the Moon visible from Earth.

1. FELDSPATHIC BRECCIAS (4 [or more] lithological types)

a. Regolith breccia (e.g. DaG 262)

b. Fragmental breccia (e.g. Dho 081)

c. Impact-melt breccia (e.g. Dho 302 and pairings, NWA 482)

d. Granulitic brecia (e.g. Dhofar 026, Dhofar 733, NWA 4483 and pairings, NWA 5744)

2. MAFICOne of the two broad categories of silicate minerals, the other being felsic, based on its magnesium (Mg) and/or iron (Fe) content. Mafic indicates silicate minerals that are predominantly comprised of Mg and/or Fe.The term is derived from those major constituents: Magnesium + Ferrum (Latin for iron) + ic (having, Th-RICH, IMPACT-MELT BRECCIAS (e.g. NWA 4472/4485 [KREEP-rich; 6.9 ppm Th], Dhofar 925/960/961/SaU 449 [KREEP components; ~2 ppm Th], SaU 169 [KREEP-rich w/ 13 vol% 2a component; 32.7 ppm Th])

3. MINGLED BRECCIAS (2 categories)

a. Predominantly feldspathic (e.g. Calcalong Creek [25% KREEP-norite; 4.3 ppm Th], Dho 1180 [KREEP clastA mineral or rock fragment embedded in another rock.; 0.9 ppm Th], NWA 2995, SaU 169, Y-983885 [KREEP clasts; 2 ppm Th])

b. Predominantly basaltic (e.g. Apollo 15 & 17 regolith samples, Kalahari 008/009, NWA 773 clan [w/ 1a, 1b, 4, and KREEP-rich components], NWA 3136, QUE 94281)

4. MAREBroad low plains surrounded by basin-forming mountains, originally thought to be a sea (pl. maria). This term is applied to the basalt-filled impact basins common on the face of the Moon visible from Earth.   BASALTS (unbrecciated) (e.g. Dho 287 [w/ 5 vol% 1a component], LAP 02205 and pairings, NEA 003, NWA 032/479, NWA 4734, NWA 4898, NWA 12008)

OTHERS

ANGRITES (3 subgroups, possibly representing two daughter asteroidal bodies)

1. Basaltic/Quenched; daughter 1 (e.g. Asuka 881371/12209 [picritic], D’Orbigny, LEW 87051 [picritic], NWA 1296, NWA 1670 [picritic], NWA 7203 [photo courtesy of Labenne Meteorites], NWA 7812 [picritic], NWA 12320, Sah 99555, Y-1154)

2. Subvolcanic/Hypabyssal; daughter 2 (e.g. LEW 86010, NWA 4590, NWA 10463, NWA 12004)

3. PlutonicGeology: Igneous intrusive body that forms when magma is injected into host rocks and solidifies. Plutons occur in the crust of asteroids undergoing differentiation or planets. Named after Pluto, the Roman god of the underworld. Plutonic rocks are the rocks found within a pluton. Astronomy: Category of planet including all/Metamorphic; daughter 2 (e.g. Angra dos Reis [pyroxenitic], NWA 2999 and pairings [peridotitic], NWA 4801, NWA 8535 [dunitic; photo courtesy of Habib Naji])

AUBRITESAubrites are named for the Aubres meteorite that fell in 1836 near Nyons, France. They are an evolved achondrite that is Ca-poor and composed mainly of enstatite (En100) and diopside (En50Wo50) with minor amounts of olivine (Fa0) and traces of plagioclase (An2-8).  They contain large white crystals of enstatite as (2 groups/parent bodies)

1. Main-group, light-REE-depleted (e.g. Aubres, Cumberland Falls, Mayo Belwa [IMB], NWA 1235 [An], NWA 4537, NWA 4799, NWA 4832, NWA 4871 [possibly paired with NWA 4799], NWA 6350 [paired with NWA 5217], NWA 6675, Peña Blanca Spring)

2. Metal-rich, light-REE-enriched (e.g. Larned [anom], Mount Egerton [anom], NWA 2526 [Enst achon])

UNGROUPED ACHONDRITES (e.g. Bunburra Rockhole [eucrite-like, possibly related to A-881394; photo courtesy of Imperial College London], Dhofar 732 [olv–opx], Ibitira [eucrite-like], AhS MS-MU-036 [enst achon], NWA 011 and pairings, NWA 1240, NWA 1840 [enst achon], NWA 2824 [eucriteMost common type of achondrite meteorite and a member of the HED group. Eucrites are basalts composed primarily of pigeonite and anorthite (An60-98). Eucrites have been placed into three subgroups based on mineralogical and chemical differences. • Non-cumulate eucrites represent the upper crust that solidified on a magma ocean after/Ibitira-like], NWA 4284 [L-like; abstract], NWA 4741, NWA 5400 and pairings, NWA 5517 [possibly related to NWA 7325; abstract], NWA 5721, NWA 5958, NWA 6698 [LL-like diorite; abstract], NWA 6704 and pairings [CC-related], NWA 6962, NWA 7325, NWA 7822 [CV-related], NWA 7835 [photo courtesy of Stefan Ralew], NWA 8054 [abstract; prob lod-anom]; NWA 8671 [eucrite-like; abstract], NWA 8777 [abstract], NWA 11119 [possibly related to NWA 7325; photo courtesy of Carl Agee; NWA 11187 [ureilite-like; abstract], NWA 11575 [LL-like trachyandesite; abstract 1, 2], NWA 12217 [dunite breccia; abstract], NWA 12338 [eucrite-like; abstract], Pasamonte [eucrite-like], PCA 82502/91007 [eucrite-like], Shallowater [enst achon])

STONY-IRONS

MESOSIDERITES subgroupings after Hewins (1984)
based on metamorphic grade (0–4) and orthopyroxene content (A–C)

0B (e.g. NWA 1878)

1A (e.g. Vaca Muerta, Crab Orchard, Patwar, Mount Padbury, Barea)

1B (e.g. Chinguetti, ALHA77219 and pairings)

2A (e.g. Clover Springs, Veramin, NWA 1242)

2B (reclassified as 4B under Hewins) (e.g. NWA 1817, NWA 6436)

2C (e.g. NWA 1827, JaH 203 and pairings)

3A (e.g. Emery, Lowicz, Morristown, NWA 1961)

3B (reclassified as 4B)

4A (e.g. Estherville [3/4A])

4B (e.g. Bondoc, Mincy)

PALLASITES 3 groups along with ungrouped members
(Mittlefehldt, 1999; Wasson et al., 2002; Wasson and Choi, 2003; Hsu, 2003; Gregory et al., 2016)

1. Main-group (2 subgroups [after Ali et al., 2018] and subgroup not yet determined)

A. high-Δ17O-bearing (ave. –0.166 [±0.014] ‰) (e.g. Acomita, Ahumada, La’gad 002 [anom metalElement that readily forms cations and has metallic bonds; sometimes said to be similar to a cation in a cloud of electrons. The metals are one of the three groups of elements as distinguished by their ionization and bonding properties, along with the metalloids and nonmetals. A diagonal line drawn; plessite], Brenham [anom metal; Ge, Ga], Finmarken, Hambleton, Huckitta [anom metal; Ge, Ga, Pt, W, Ir], Imilac, Jay Bird Springs, Marjahlati, Otinapa, Pallasovka, Somervell County, South Bend, Springwater [anom silicates; Fa, P-ol], Sterley, Thumrayt 001)

B. low-Δ17O-bearing (ave. –0.220 [±0.009] ‰) (e.g. Brahin [anom silicates; P-ol], Esquel, Fukang, Giroux, Hambleton, Krasnojarsk [anom metal; Co, As, Sb, Ni, Cu], Mount Dyrring, Newport, Seymchan [anom metal; Ir])

*subgroup not yet determined (e.g. Albin, Argonia [anom metal; Ir], Cumulus Ridge 04071 and pairings [anom metal; AuThe astronomical unit for length is described as the "mean" distance (average of aphelion and perihelion distances) between the Earth and the Sun. Though most references state the value for 1 AU to be approximately 150 million kilometers, the currently accepted precise value for the AU is 149,597,870.66 km. The, Ge], Conception Junction [anom metal; Ni, Cu, Co, Ga, As, Ir], Glorieta Mountain [anom metal; Ge, Ga], Jepara, Mineo, Mount Vernon, Omolon [anom metal; kamacite], Pavlodar [anom metal; Au], Phillips County [anom silicates; Fa, FeS, Ni], Rawlinna 001 [anom silicates; Fa, Ni, Co, Cu, P-ol], Sericho, Theil Mountains, Zaisho [anom silicates; Fa, P-ol])

2. Eagle Station group (possibly CK- or CO-related) (e.g. Cold Bay, Eagle Station, Itzawisis, Karavannoe, Oued Bourdim 001)

3. PyroxeneA class of silicate (SiO3) minerals that form a solid solution between iron and magnesium and can contain up to 50% calcium. Pyroxenes are important rock forming minerals and critical to understanding igneous processes. For more detailed information, please read the Pyroxene Group article found in the Meteoritics & Classification category. group (e.g. LoV 263, NWA 1911/Zinder duo, NWA 10019, ‘Vermillion Pallasites’ [Choteau, Vermillion, Y-8451])

Ungrouped (e.g. Milton [‘CX’ trend])

IRONS

CHEMICAL GROUPS

IAB complex (Wasson and Kallemeyn, 2002)

1. main group (e.g. Campo del Cielo, Canyon Diablo, DaG 962, Landes, Odessa)

2. subgroup sLL (e.g. Toluca, Deport, NWA 2311, NWA 8346, Zagora)

3. subgroup sLM [formerly IIIC](e.g. Carlton, Lamesa, Maltahöhe, NWA 2680)

4. subgroup sLH [formerly IIID](e.g. Dayton, Freda, NWA 3206, Tazewell)

5. subgroup sHL (e.g. Chebankol, Hassi-Jekna, Lonaconing, NWA 2151, NWA 3200/4706/4710, NWA 8348, NWA 11577, Quarat al Hanish)

6. subgroup sHH (e.g. ALHA80104, Garden Head, Gay Gulch, Kofa, Mount Magnet, NWA 4701)

7. Udei Station grouplet (e.g. Caddo County, Four Corners, Udei Station, Zagora)

8. Pitts grouplet (e.g. Pitts, Woodbine)

9. Algarrabo duo (Algarrabo, Livingston)

10. Mundrabilla duo (Mundrabilla, Waterville)

11. Britstown duo (Britstown, EET 87506)

12. NWA 468 duo (NWA 468, GRV 98003) note: NWA 468 has been reclassified as anomalous lodranite; Sanborn et al., 2014)

13. Twin City duo (Twin City, Santa Catharina)

14. IAB-related irons (e.g. Georgetown, NWA 4861 [sHL-related], NWA 5804 [ungr], Oktibbeha County)

IC (e.g. Arispe)

IIAB (e.g. Auburn, Carver, Coahuila, Guadalupe y Calvo, Sikhote Alin)

IIC (e.g. Ballinoo, Cratheús [1950], Darinskoe, Kumerina, Perryville, Salt River, Unter Mässing, Wiley)

IID (e.g. Carbo, Needles)

IIE (2 categories [after McCoy, 1995; Van Roosbroek et al., 2015])

1. With silicate inclusions (2 metamorphic subtypes)

A. chondritic/unfractionated (e.g. Garhi Yasin, Mont Dieu, Netshaëvo, RBT 04186, Techado, Watson 001 [evolved, impact melt], Y-791093 [transitional])

B. differentiated/fractionated (e.g. Elga, Colomera, Kodaikanal, Miles, NWA 5608, Tarahumara, TYR 05181, Weekeroo Station)

2. Without silicate inclusions (e.g. Arlington, Barranca Blanca, EET 83390, Leshan, NWA 6716, Sah 03505, Tobychan, Verkhne Dnieprovsk)

IIF (e.g. Corowa, Del Rio, Monahans [1938], Repeev Khutor)

IIG (e.g. Bellsbank, Guanaco, La Primitiva, Tombigbee River, Twannberg)

see THE BELLSBANK QUINTET: The Consummation of a New Iron Group—IIG

IIIAB (e.g. IIIA: Cape York, Wabar, Tambo Quemado; IIIAB: Whitecourt)

IIIE (e.g. Aletai [anom], Coopertown, Willow Creek)

IIIF (e.g. Klamath Falls, Nelson Co., St. Genevieve Co.)

IVA (e.g. Bishop Canyon, Descoberto [anom], Gibeon, NWA 5289, Page City, Säo Joäo Nepomuceno [anom], Steinbach [anom])

IVB (e.g. Hoba, Santa Clara)

IVC (after Litasov et al., 2017) (e.g. ALH 77255, Alikatnima, Babb’s Mill [Blake’s], Chinga, Deep Springs, Onello, Shingle Springs)

SULFIDE-IRONS (e.g. HOW 88403, MET 00428 [H chon], Sacramento Wash 005 [H chon])

UNGROUPED IRONS (e.g. NWA 176, Sombrerete, Taza, Willamette)

PART I: CHONDRITES, METACHONDRITES
PART III: MARTIAN METEORITES—GEOCHEMICAL CLASSIFICATION
PART IV: DIOGENITES—IUGS TAXONOMY
PART V: ENSTATITE CHONDRITES—SUBGROUP CLASSIFICATION

You must collect things for reasons you don’t yet understand.
Daniel J. Boorstin – Librarian of Congress

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© 1997–2019 by David Weir