Eucrites are the E class of the HED achondrite clan (howardite-eucrite-diogenite). The HED clan of meteorites represents volcanic rocks (surface flows) and plutonic rocks (deeper crystallization) formed from basaltic magmas. Eucrites, from the Greek word eukritos, meaning "easily distinguished," are probably more similar to terrestrial rocks than any other asteroidal meteorite class. Like terrestrial basalts, eucrites formed by partial melting of parent rocks and are typically extrusive (surface flows). They are also referred to as "basaltic achondrites" because of their similarity to terrestrial basalts in texture and gross mineralogy, but differ in bulk composition and other characteristics. For example, they contain reduced, metallic nickel-iron (Ni-Fe) instead of oxidized iron minerals, e.g., magnetite (Fe3O4).
Eucrites are composed of orthopyroxene, pigeonite, Ca-rich pyroxenes and plagioclase with minor amounts of chromite, ilmenite, troilite and Ni-Fe metal. A few eucrites, e.g., Moore County are similar to terrestrial gabbros (plutonic rocks) in having cumulate textures (preferred orientation of major minerals) that indicate crystal layering by settling-out in a magma chamber, analogous to the accumulation of fallen tree leaves into layered piles.
Basaltic eucrites are typically brecciated (monomict or polymict). Either orthopyroxene or pigeonite will be present.
Minerals and compositions:
Texture: Basaltic eucrite textures are highly variable, mostly subophitic and ophitic, but may include phyric and variolitic textures, in addition to shock-formed textures, e. g., microgranular, quench, and microphenocrystic. Cumulate eucrites are commonly protogranular with equal amounts of pyroxene and plagioclase.
United Arab Emirates
Find: 2006
Achondrite (eucrite)
Physical characteristics: A dark, 54 g completely crusted stone.
Petrography: (T. Bunch and J. Wittke, NAU). Eucrite breccia with ophitic to subophitic textures. Contains pigeonite, augite, plagioclase, FeS, metal, and SiO2. Pigeonite cores are rimmed by subcalcic augite. Pigeonite basal sections show well-developed twinning and plagioclase has extensive Carlsbad-albite twinning. Mesostasis pockets consist of fine-grained intergrowths of plagioclase, SiO2, and FeS.
Mineral compositions and geochemistry: Pigeonite cores (Fa41.4Wo8.2; FeO/MnO = 30), subcalcic augite rims (Fs46Wo21.6; FeO/MnO = 29) and plagioclase (An84.2–92.2).
Classification: Achondrite (eucrite); minimal shock, minimal weathering with minor carbonate/ iron oxide veins.
Type specimen: A 10.8 g sample is on deposit at NAU. The main mass holder is anonymous.
United Arab Emirates
Find: 2005
Achondrite (eucrite, monomict breccia)
Physical characteristics: A brownish 146 g stone, with no fusion crust, partially desert-etched by sandblasting.
Petrography: (J. Wittke and T. Bunch, NAU) Porphyroclastic texture of relict cumulate basalt clasts surrounded by a fine-grained matrix of recrystallized basalt. Thin, shock-melt veins transcend the sample. Prominent iron oxide staining surrounds metal grains.
Mineral characteristics and geochemistry: Pigeonite (Fs52.5Wo8.7; FeO/MnO = 33), augite (Fs42.8Wo27.2), chromite (Cr/[Cr + Al] = 0.75), and plagioclase (An90.5).
Classification: Achondrite (eucrite, monomict breccia); moderate shock and weathering.
Type specimen: A 21 g sample is on deposit at NAU. The main mass holder is anonymous.
United Arab Emirates
Find: 2005
Achondrite (eucrite, monomict breccia)
Physical characteristics: A 67 g stone that has somewhat weathered fusion crust and desert staining.
Petrography: (J. Wittke and T. Bunch, NAU) A fine-grained, eucrite monomict breccia. Ophitic- to subophitic-textured, plagioclase contains numerous, tiny (<0.02 mm) oriented euhedral pyroxene crystals. Has a moderate degree of undulatory extinction in plagioclase and pyroxenes. Contains
orthopyroxene, pigeonite, augite, plagioclase, ilmenite, chromite, FeS, and metal.
Mineral compositions and geochemistry: Orthopyroxene host (Fs56.6Wo2.2; FeO/MnO = 29), augite exsolution lamellae (Fs28.8Wo43.6), pigeonite (Fs52Wo8.7; FeO/MnO = 33), and chromite (Cr[Cr + Al] = 0.84).
Classification: Achondrite (eucrite, monomict breccia); minimal shock and weathering.
Type specimen: A 13.5 g sample is on deposit at NAU. The main mass holder is anonymous.
Oman
Find: March 2006
Achondrite (eucrite, monomict breccia)
History and physical description: An 89 g stone that is covered with very fresh fusion crust, was found in the Dhofar region of Oman by R. Ward 0n March 5, 2006.
Petrography (T. Bunch and J. Wittke, NAU): partially recrystallized monomict breccia. Relict textures include fine-grained subophitic transitional to variolitic. The matrix is a mixture of finely comminuted to recrystallized zones. Narrow shock veins transect the specimen and plagioclase, in relict basalt clasts, is partially converted to maskelynite.
Mineral compositions and geochemistry: Relict basalt clasts: orthopyroxene (Fs60.3Wo2.2, FeO/MnO = 32), pigeonite (Fs51.2Wo12.3, FeO/MnO = 30), augite (Fs25Wo45.3), chromite (Cr/[Cr+Al] = 0.81) and metal (Ni = 0.27 wt%).
Classification: achondrite (eucrite, monomict breccia). Weathering grade is extremely low and the shock level has a range of medium to high.
Type specimen: A sample of 18.8 g is on deposit at NAU. R. Ward holds the main mass.
Morocco
Found 2001
Achondrite (polymict eucrite)
A 3279 g, crusted stone was purchased in Rissani, in 2001. Classification and mineralogy (T. Bunch and J. Wittke, NAU): modal analyses (area of 34 cm2), eucritic basalts 94 vol%; shock melt clasts, 4 vol%, diogenites 2 vol%. At least 34 different eucrite clasts were observed that range from micro-ophitic/subophitic (<0.1 mm) to cumulate to very-coarse grained gabbroic (3-7 mm). Gabbro pyroxenes are predominantly 2-5 mm in size subcalcic ferroaugites (TiO2 = 0.9 to 2.1 wt%) with 3-6 mm plagioclase, An92; ilmenite, chromite (Al2O3 = 9.2 wt%), and acicular crystals of tridymite up to 7 mm in length. Shock stage, S2; weathering grade, variable, W1 to W2. Specimens: type specimen, 18.4 g and three thin sections, NAU; main mass is with the purchaser.
Morocco
Found 2002
Achondrite (cumulate eucrite, polymict)
A 28.84 g stone was purchased in Rissani, Morocco in 2003. Classification and mineralogy (T. Bunch and J. Wittke, NAU): polymict cumulate eucrite that contains a variety of shocked clasts (shock level, S3-S5). Low-Ca pyroxenes range from Fs42Wo3.4 to Fs52.4Wo12.2; plagioclase, An92.1-94.4; minor ilmenite, chromite, sulfides, and silica. Several cumulate pigeonites contain melt inclusions (0.024 to 0.065 mm diameter) of micron to submicron pyroxenes, plagioclase, and glass. Defocused microbeam analyses indicate bulk compositions similar to those suggested by Treiman (1997) to represent eucrite parent magmas. Very fresh crust and interior. Specimens: 5.7 g, NAU; main mass, Oakes.
Morocco
Found 2002
Achondrite (cumulate eucrite, monomict)
A 1102 g partially crusted, single stone was purchased in Rissani, Morocco in 2003. Classification and mineralogy (T. Bunch and J. Wittke, NAU): highly contorted mass of eucrite clasts with cataclastic mantles that are in turn covered by partially melted to recrystallized masses. Cumulate texture with subophitic enclaves. Clast orthopyroxene, Fs56.4-59Wo2.5-4; exsolution lamellae, Fs43.4-46.3Wo23-25.6; recrystallized zone, Fs54.5-57.5Wo8.4-13.5. Chromite, Cr/(Cr + Al) = 0.85, TiO2 = 14.6 wt% with exsolution lamellae of ilmenite; plagioclase, An91-93.6. Shock level, S1 to S5. Very fresh. Specimens, 25.5 g, NAU; main mass, Oakes.
Morocco
Found 2001
Achondrite (eucrite, cumulate)
A 980 g, complete and very fresh stone was purchased in Rissani, January 2002. Classification and mineralogy (T. Bunch and J. Wittke, NAU): monomict, orthocumulate eucrite breccia. Contains cumulate, unzoned plagioclase An89-90 (N=24); orthopyroxene with tight compositional cluster at Fs65Wo2 (N=36) and exsolution lamellae of augite, Fs28Wo44; minor TiO2-rich (18.2 wt%) to TiO2-poor (<3 wt%) chromite is present as inclusions in pyroxene. Microbreccia shear zones and plastic deformation of adjoining minerals with melt pockets are common within clasts. Non-sheared clasts are S1. Specimens: type specimen, 20.6 g, NAU; main mass, Farmer.
Morocco
Found 2001
Achondrite (eucrite, monomict)
A 1.2 kg, complete and very fresh stone was purchased in Rissani, January 2002. Classification and mineralogy (T. Bunch and J. Wittke, NAU): monomict breccia with subophitic to microgabbroic clasts of zoned plagioclase (cores: An91; rims: An80Or1), zoned pigeonite (cores: Fs37Wo7; rims: Fs53Wo11) and zoned subcalcic ferroaugite (cores: Fs47Wo20; Rims: Fs49Wo24). Minor phases include ilmenite, chromite, silica, and pyrrhotite. Inclusions of granular Fe-rich olivine (Fo81) and metal (0.31 wt% Ni; 1.4 wt% Co) are present in pigeonite. Specimens: type specimen, 20.9 g, NAU; main mass, Farmer.
Morocco
Found 2001
Achondrite (eucrite)
A single, 86 g, complete stone was purchased in Tagounite in 2002 April. Classification and mineralogy (T. Bunch and J. Wittke, NAU): gabbroic, cumulate eucrite; tabular crystals of plagioclase (<4 mm in longest dimension) poikilitically enclosed by large pyroxenes (up to 8 mm). Plagioclase is An91 with melt inclusions of a silica polymorph, Mg-augite, and ilmenite. Complex pyroxenes consist of inverted pigeonite (Fs52.5Wo4.2) with broad (5-8 µm) augite exsolution lamellae (Fs25Wo41) parallel to (100) of host orthopyroxene and blebs of augite that exsolved prior to or during pigeonite inversion. In addition, relic patches of pigeonite contain fine augite lamellae parallel to (001). Chromite, Cr/[Cr+Al] = 63-73, pyrrhotite, and tiny inclusions of orthopyroxene in Ni-poor metal (Ni = 0.48 wt%; Co = 2.28 wt%) are also present. No ilmenite or silica was found outside of melt inclusions. Shock level, S2/3; weathering grade, W1. Specimens: type specimen, 17.2 g, NAU; main mass, Farmer.
Morocco
Found 2002
Achondrite (eucrite)
A 546 g fully crusted stone was purchased in Erfoud in 2002. Classification and mineralogy (T. Bunch & J. Wittke, NAU): monomict, cumulate eucrite breccia; clast size, millimeters to 6 cm; cataclastic, microgranular veining with minor recrystallization. Inverted pigeonite (Fs48Wo2.5); augite lamellae (Fs15Wo46); plagioclase (An93); sulfide, ilmenite, chromite (Cr/[Cr+Al] = 65), and metal (Ni = 7.1 wt%). Shock level, S3/4; reduced birefringence, mosaicness, and deformation lamellae in pyroxenes; minor development of maskelynite. Very fresh, shiny black fusion crust and un-oxidized metal; minor terrestrial carbonate alteration veins. Specimens: 23 g, NAU; main mass, Boswell.
Morroco
Found 2002
Achondrite (polymict eucrite)
A 197 g complete and crusted stone was purchased in Erfoud, Morocco in 2003. Classification and mineralogy (T. Bunch and J. Wittke, NAU): unique, highly shocked (S5) polymict breccia. Flow orientation of partially granulated clasts; elongated melt pockets with fine-grain crystallites of plagioclase, pyroxenes, and silica, and minor remnant glass. Pyroxenes: extensive development of planar deformation features and fractures, reduced birefringence, and minor recrystallization; presence of maskelynite. Eucrite clasts: 82 vol% are cumulate, 18 % are basaltic. Cumulate pyroxenes: orthopyroxene mean = Fs49Wo13, FeO/MnO = 27.4; exsolved augite, Fs15Wo44; pigeonite mean = Fs42 Wo13, FeO/MnO = 29.3; anorthite range, An70.3-92.8. Minor ilmenite, sulfides, phosphate, and silica polymorph. Very fresh, no apparent iron staining. Specimens: 21.3 g, NAU; main mass, Boswell.
Morocco
Found 2003
Achondrite (eucrite, cumulate)
A 69.15 g, nearly complete stone, was purchased in Rissani, Morocco, September 2003. Classification and mineralogy (J. Wittke and T. Bunch, NAU): remarkably fresh cumulate eucrite with minor recrystallization. Textural characteristics similar to Moore County, grains size < 3 mm with cumulate plagioclase. Pigeonite = Fs56.5Wo8.5; ferroaugite = Fs31Wo40. Plagioclase is An88 and chromite Cr/[Cr+Al] = 0.85. Minor ilmenite and troilite. No evident shock characteristics. Specimens: 15.1, NAU; main mass, Farmer.
Morocco
Found 2003
Achondrite (eucrite, basaltic)
A 33 g complete stone was purchased in Rissani, Morocco, September 2003. Classification and mineralogy (J. Wittke and T. Bunch, NAU): unbrecciated subophitic eucrite; fine grain size (<one mm). Shock decorated plagioclase and pyroxene; shock veins transcend the entire sample; shock level, S3. Pigeonite, Fs54Wo8; augite, Fs31Wo42.6; plagioclase. An91.3. Rare metal, Ni = 0.23; Co = 0.21; minor ilmenite, troilite, and silica. Light oxidation and staining. Specimens: 6.5 g, NAU; main mass, Farmer.
Morocco
Found 2003
Achondrite (eucrite, polymict)
A 125.2 g complete stone was purchased in Rissanni, September 2003. Classification and mineralogy (T. Bunch and J. Wittke, NAU): Polymict eucrite; modes in vol%: cumulate eucrite, 74, basaltic eucrite, 17, diogenite 6, shock clasts, 3. Cumulate eucrite orthopyroxene, Fs46.7-54.7Wo2-3.1; augite, Fs38.4-44Wo20-24.4; plagioclase, An89.4. Minor metal (Ni = 0.57 wt%; Co = 0.42), ilmenite, chromite, troilite and silica. Shock level, S2; minor weathering. Specimens: 20.7 g, NAU; main mass, Farmer.
Morocco
Found 2003
Achondrite (eucrite, polymict cumulate)
A 45.8 g complete stone was purchased in Rissani, Morocco, September 2003. Classification and mineralogy (T. Bunch and J. Wittke, NAU): hand specimen is medium to very dark gray; highly shocked (to S6), polymict cumulate eucrite; maskelynite, recrystallized plagioclase and pyroxenes, crystallized melt pockets. Orthopyroxene (avg.), Fs50.7Wo3; pigeonite, Fs47.5Wo10.2; plagioclase and maskelynite, An88.8-90.3. Minor ilmenite, sulfides, and chromite, Specimens: 5.35 g, NAU; main mass, Farmer.
Morocco
Found 2003
Achondrite (eucrite)
A 135 g very fresh and fully crusted complete stone was purchased in Erfoud, July 2003. Classification and mineralogy (T. Bunch and J. Wittke, NAU): unbrecciated, porphyritic basalt with long (up to 9 mm) phenocrysts of low-Ca pyroxenes set in a matrix of smaller pyroxenes and blocky to acicular plagioclase. Clots (3 to 8 mm in diameter) of low-Ca pyroxene phenocrysts set in radiating bundles of plagioclase (variolitic texture) are distributed throughout the specimen. Main mass, low-Ca pyroxene phenocrysts are zoned from cores of Fs29.8Wo4.9 to pigeonite rims of Fs49Wo12; Fe/Mn = 29.8 and 37.2, respectively. Small inclusions of metal (Ni = 0.05 to 0.25 wt%) are sparsely distributed. Blocky to acicular plagioclase is An83.7Or2 with a small compositional range. All plagioclase, regardless of size and morphology, contains up to 0.97 wt% FeO. Clot pyroxene cores are Fs42.9Wo28 (Fe/Mn = 35.6) and rims are Fs49.2Wo25.1 (Fe/Mn = 36.1). Very fresh with no apparent weathering; shock level, S2. Specimens: type sample, 21.7 g, NAU; main mass, Boswell.
Morocco
Found 2003
Achondrite (eucrite)
A 50.3 g partial stone with 20 % crust was purchased in Erfoud, July 2003. Classification and mineralogy (J. Wittke and T. Bunch, NAU): fine-grained subophitic to intergranular basalt with recrystallized, cataclastic enclaves and thin, shock-melt veins. A swirling flow pattern of solidifying magma is evident. Orthopyroxene compositions are tightly clustered around Fs63.1Wo2.1 (Fe/Mn = 32.7); Ca-rich pyroxene centered about Fs25.2Wo48.1. Plagioclase, An91.3. Minor phases include silica, ilmenite, chromite, low Ni-metal, and phosphate. Weathering grade, W1: exterior iron oxides and caliché; slight interior staining. Shock level is variable from S2-S4. Specimens: 13.8 g, NAU; main mass, Boswell.
Morocco
Found 2003
Achondrite (eucrite, monomict)
A 95.8 g partial stone with 50 % crust was purchased in Erfoud, July 2003. Classification and mineralogy (J. Wittke and T. Bunch, NAU): Coarse grained variolitic to subophitic with sparse, large (2-4 mm) orthopyroxene phenocrysts; small (< 1-3 mm) enclaves of fine-grained variolitic texture without phenocrysts; lightly brecciated with minor recrystallization. Opx phenocrysts, Fs58.5Wo2 (Fe/Mn = 29.6-32.8); matrix augite, Fs24.8Wo3.6; plagioclase, An81.7Or5. Minor chromite, ilmenite and silica. Incipient maskelynite, planar fractures, mosaicness, and reduced birefringence in pyroxenes; shock level, S3/4. Interior very fresh, Specimens, type sample, 20.8 g NAU; main mass, Boswell.
Morocco
Found 2003
Achondrite (eucrite, cumulate)
A 94.4 g complete and fully crusted stone was purchased in Erfoud, July 2003. Classification and mineralogy (T. Bunch and J. Wittke, NAU): coarse-grained (< 3.2 mm) cumulate basalt; cumulate plagioclase with intercumulate pyroxene and minor ilmenite. Plagioclase, An91.8Or1; orthopyroxene, Fs49.5Wo1.8 with exsolution lamellae of Fs41.5Wo12.8; augite, Fs9.1Wo44. Subrounded, cm-size clasts set in finely crushed, unrecrystallized matrix; shock level, S1. Very fresh with no apparent weathering; shiny fusion crust. Specimens: 21.1 g, NAU; main mass, Boswell.
Morocco
Found 2003
Achondrite (eucrite)
A 58 g partial stone with 40 % crust was purchased in Erfoud, July 2003. Classification and mineralogy (T. Bunch and J. Wittke, NAU): monomict breccia of highly variable textures: fine-grained (< 1 mm) cumulate to subophitic with a partial overlay of metamorphic-granular (prominent 120° triple junctions). Cumulate areas; orthopyroxene host Fs58.2Wo2.1, exsolution lamellae, Fs25Wo45; plagioclase, An90.1, Cr/[Cr+Al] = 0.877; subophitic Ca-poor pyroxene, Fs62.3Wo5 with exsolved Fs27Wo43.9. This specimen probably sustained high shock levels, but shock indicators were mostly annealed-out during post-impact metamorphism. Very fresh, little apparent weathering. Specimens: type, 11.6 g, NAU; main mass, Boswell.
Morocco
Found 2003
Achondrite (eucrite, monomict)
A 58.2 g complete stone with 90 % crust was purchased in Erfoud, July 2003. Classification and mineralogy (J. Wittke and T. Bunch, NAU): brecciated, medium to coarse-grained (< 3 mm) ophitic to subophitic basalt. Orthopyroxene Fs61.8Wo2.2 with exsolved augite lamellae of Fs25.4Wo45.4; plagioclase, An91.2; chromite, Cr/[Cr+Al] = 0.85 and minor ilmenite, silica, sulfide and phosphate. Minor recrystallization of shocked pyroxenes and annealing of plagioclase and pyroxenes (shock decorations); incipient maskelynite, and parallel fracturing in pyroxenes; shock level, S3/4. Dull fusion crust and minor staining. Specimens: type, 11.5 g, NAU: main mass, Boswell.
Morocco
Found 2002
Achondrite (eucrite, monomict)
A 496 g, partial stone with 70 % fusion crust, was purchased in Rissani, March 2002. Classification and mineralogy (T. Bunch and J. Wittke, NAU): brecciated basalt with < 15 vol% cataclastic matrix; clast grain size range, 1.5 mm to 0.4 mm; cumulate texture with strong, preferred orientation of plagioclase and pyroxene crystals in flow-like patterns in most clasts. Orthopyroxene, Fs55-61 Wo1.5-2.1; exsolution lamellae; Fs44-47Wo15-21; plagioclase more sodic than most typical eucrites; An77-82Or2.5-4.1; minor silica, ilmenite and chromite. Shock level, S3; well-developed parallel fracturing and mosaicism in pyroxenes and reduced birefringence in major minerals. Very fresh interior with greenish appearance. Specimens: 21.3 g, NAU; main mass, Moroccan Imports, Imperial Beach, CA USA.
Northwest Africa
Purchased 2004
Achondrite (monomict eucrite)
A 322.4 g stone was purchased in Erfoud, Morocco in January 2004. Description and classification (J. Wittke and T. Bunch, NAU): a monomict breccia that is mostly composed of metabreccia clasts. Some of these clasts contain fragments of coarse-grained (between 2 and 3 mm) cumulate basalts surrounded by partially recrystallized, finer-grained pyroxenes and plagioclase of similar compositions. Large, cumulate pyroxenes typically show strong core to rim compositional zoning; cores range from Fs36.1Wo4.8 to Fs39.5 Wo7.4 with rims of ~ Fs54.8Wo14.6; plagioclase, An84.4. Shock level, S1-2; many shock features were apparently annealed out during post-shock metamorphism. Specimens: 22.8 g, NAU; main mass, Farmer.
Northwest Africa
Found 2003
Achondrite (cumulate eucrite)
A 67 g partial stone with fresh fusion crust was purchased in Erfoud, Morocco, April 2004. Description and classification (T. Bunch and J. Wittke, NAU): highly crushed monomict, granular to subophitic eucrite breccia; mm-sized (up to 2.4 mm) orthopyroxene and plagioclase both of which show prominent twinning; orthopyroxene also contains thin exsolution lamellae of Ca-rich pyroxene. Orthopyroxene, Fs46.5Wo2.8; augite, F26Wo34.2; plagioclase, An91, chromite, Cr[Cr+Al] = 0.81 and Mg/(Mg+Fe) = 0.23; metal, Ni = 0.56 wt%, and minor ilmenite. Shock level is S2-S4 with very thin melt veins that traverse the entire surface of a 5 cm long slice; limited maskelynite development. No apparent internal weathering. Specimens: type sample, 14.4 g NAU; main mass, Strufe.
Northwest Africa
Purchased January 2004
Achondrite (polymict eucrite)
A 67 g complete stone, partially crusted, was purchased in Erfoud, Morocco. Description and classification (T. Bunch and J. Wittke, NAU): highly shocked (S3-5), medium-grained, polymict eucrite. Dominate lithology consists of orthopyroxene, Fs38.4Wo1.9 with exsolution lamellae of augite, Fs20.3Wo40.4, pigeonite, Fs34.4Wo13.7, plagioclase, An89.2, and chromite, Cr/[Cr+Al] = 62. The subordinate lithology contains orthopyroxene, Fs47.2Wo2.0; pigeonite, Fs43.2Wo14.7, plagioclase, An93.2 and chromite, Cr/[Cr+Al] = 0.701. Minor amounts of ilmenite and metal occur in both lithologies. Nearly 90 vol% of pyroxenes and plagioclase in both lithologies are shock-recrystallized; very light weathering grade. Specimens: 13.6 g, NAU; main mass, anonymous collector.
Northwest Africa
Purchased 2003
Achondrite (polymict eucrite)
A complete and mostly crusted stone that weighted 227 g was purchased in Erfoud, Morocco. Description and classification (T. Bunch and J. Wittke, NAU): highly varied assortment of fine- to coarse-grained (0.2 to 3.4 mm) cumulate, ophitic, subophitic, microgranular to granular eucrites, howardite xenoliths, and shock melt clasts; numerous, discontinuous melt veins up to 1.6 mm in thickness. Coarse-grained cumulate pyroxenes range from Fs35.9Wo1.9 to Fs44.1Wo6.6; plagioclase, An90.6. Typical non-cumulate, low Ca pyroxenes, are Fs56.Wo5.8, Ca-rich pyroxenes, Fs32Wo35.3; plagioclase, An87. Melt veins have a limited compositional range and average (major oxides only): SiO2, 48.3 wt%; Al2O3, 15.7 wt%, FeO, 14.7 wt%, MgO, 6.2 wt% and CaO, 13.4 wt%. Shock level: S2-6; low degree of weathering. Specimens: 26.2 g, NAU; main mass, Hupé.
Northwest Africa
Purchased 2004
Achondrite (polymict eucrite)
A small (40.1 g) partial stone was purchased in Erfoud, Morocco in January 2004. Description and classification (J. Wittke and T. Bunch, NAU): polymict eucrite that contains clasts (70 vol%) of very fine-grained (<0.01 mm) recrystallized pyroxene, plagioclase, and ilmenite together with sparse, relict megacrysts of pyroxene and plagioclase of similar compositions. Other clasts are partially recrystallized cumulate eucrites that are probably precursors of the recrystallized material. Recrystallized pyroxene, Fs61.2±1.2Wo5.7±1.1, FeO/MnO = 28.3; plagioclase, An91.1. Cumulate pyroxene, Fs56.3-62.4Wo2.3-8.9, FeO/MnO = 26.7-28.8; plagioclase, An92.1. Shock level, S5; very low grade weathering. Specimens: 8.2 g, NAU; main mass, Oakes.
Northwest Africa
Purchased 2004
Achondrite (eucrite)
A single crusted stone of 506 g was purchased in Rissani, Morocco in January 2004. Description and classification (J. Wittke and T. Bunch, NAU): fine grained (<1 mm) subophitic eucrite basalt with numerous, cross cutting fractures (microns to hundreds of microns wide) that are filled with melt glasses. Orthopyroxene, Fs61.9Wo1.9, FeO/MnO = 26.6-30.8; pigeonite, Fs55.3Wo9; augite, Fs27.3Wo42; plagioclase, An88.3; Chromite, Cr/[Cr+Al] = 88.3. Also present are minor amounts of silica, metal and ilmenite. Shock level, S2-3 (melt glasses are injected); slightly weathered. Specimens: 21.7 g, NAU; main mass, Boswell.
Northwest Africa
Purchased 2004
Achondrite (polymict eucrite)
A single, complete and partially crusted stone was purchased in Rissani in January 2004. (T. Bunch and J. Wittke, NAU): contains an array of cumulate basaltic clasts of highly variable grain size (0.15 to 3.2 mm) and ~ 16 vol% of opaque, shock-melt xenoliths. The compositional range of major minerals in 9 cumulates (9 analyzed ) is rather small: orthopyroxene, Fs43Wo2.2 to Fs47.7Wo3.2; pigeonite, Fs40.4Wo13.8 to Fs46.6Wo14.2; plagioclase, An93.8- 94.5; chromite, Cr/[Cr+Al] = 0.68 to 0.74. Compositional similarities may suggest that many of these basalts may be related to a single volcanic event. Shock level, S2 and low weathering grade. Specimens: 21 g, NAU; main mass, Boswell.
Northwest Africa
Find: 2005
Achondrite (eucrite, monomict)
History and physical characteristics: A 156 g, complete stone was purchased from a dealer in Erfoud, Morocco in 2005 by Dr. David Gregory. The stone is moderately desert ablated with a remnant translucent fusion crust.
Petrography (T. Bunch and J. Wittke, NAU): monomict breccia with granoblastic matrix and partially recrystallized ophitic and subophitic basaltic pyroxenes. Unrecrystallized pyroxenes show partially annealed shock features (“decorations”) of fractures, planar deformation features, and shock twinning. Weathering effects are very low.
Mineral compositions: pyroxene host, Fs59Wo7 (FeO/MnO = 35); lamellae, Fs32.7Wo42.1. Plagioclase is An89.1. Also present is SiO2, ilmenite. metal, and merrillite.
Classification: Achondrite (eucrite, monomict breccia)
Type specimen: A total of 21 g are on deposit at NAU. Dr. David Gregory holds the main mass.
Northwest Africa
Find: 2005
Achondrite (eucrite monomict)
History and physical characteristics: A 27 g, complete stone was purchased from a dealer in Erfoud, Morocco in 2005 by Dr. David Gregory. The stone is highly polished by desert ablation with little remaining crust and is minimally chemically weathered.
Petrography (J. Wittke and T. Bunch, NAU): cumulate eucrite monomict breccia with intense comminution of subrounded clasts. The dark matrix is composed of very fine-grained mineral fragments and glassy filaments arranged together with clasts in a flow fabric. Some maskelynite and plagioclase glass are present. Weathering effects are minimal, with slight iron staining.
Mineral compositions: host pyroxene, Fs55Wo9.3 (FeO/MnO = 34-39); exsolution lamellae, Fs36.4Wo29; augite, Fs29.2Wo40.2. Plagioclase is An91 and chromite Cr/[Cr+Al] = 0.79. FeS, SiO2, and ilmenite are also present.
Classification: Achondrite (eucrite, monomict)
Type specimen: A total of 5.5g are on deposit at NAU. Dr. David Gregory is the main mass holder.
Northwest Africa
Found 2004
Achondrite (polymict cumulate eucrite)
A 56 g complete stone was purchased in Erfoud, Morocco in March 2004. Description and classification (J. Wittke and T. Bunch, NAU): polymict, cumulate eucrite of mostly coarse-grained basaltic clasts (1 - 2.5 mm grain diameter). Most components are lightly to moderately shocked (S2-4) with a few shocked to S6. Low-Ca pyroxene, Fs37.1-43.1Wo2.8-3.7; pigeonite, Fs30.7-33.7Wo7.8-12.0; plagioclase, An88.9-92.1; chromite, Cr/[Cr+Al] = 0.77-0.85. Lightly weathered. Specimens: type specimen 22 g, NAU; main mass, Burkhard.
Northwest Africa
Found 2004
Achondrite (polymict cumulate eucrite)
A 1,298 g single stone with partial fusion crust was purchased in Erfoud, Morocco in March 2004. Description and classification (T. Bunch and J. Wittke, NAU): highly shocked, polymict eucrite breccia; up to 80 vol% of basalt clasts and mineral fragments were recrystallized into fine-grained masses (S5). In addition, earlier generated breccia clasts are present and are equally shocked; similar to NWA 2124. Average compositions are: low-Ca pyroxene, Fs54.6Wo3.2; pigeonite, Fs46.4Wo12.5; augite, Fs26.Wo40.8; plagioclase, An91.5; chromite, cr# = 87. Lightly weathered. Specimens: type specimen 21.1 g, NAU; main mass, Burkhard.
Northwest Africa
Found 2003
Achondrite (cumulate eucrite)
A 252 g partially crusted stone was purchased in Erfoud, Morocco in May 2004. Description and classification (J. Wittke and T. Bunch, NAU): unbrecciated, medium-grained cumulate eucrite that is partially recrystallized. Orthopyroxene, Fs59.3-62.9Wo1.7-3.3 (FeO/MnO = 29.3-34.5), exsolved pigeonite, Fs55.1Wo9.1; augite; Fs22.4-26.3Wo43.1-44.8; plagioclase, An89.2; chromite, cr# = 80; low Ni metal (<0.25 wt% Ni), silica, and ilmenite. Shock level, S2 and low weathering grade. Specimens: 22.0 g, NAU; main mass, Birdsell.
Northwest Africa
Found 2003
Achondrite (polymict eucrite)
Four stones with a total weight of 1239 grams were purchased in Erfoud, Morocco in May 2004. Description and classification (T. Bunch and J. Wittke, NAU): polymict breccia that contains a variety of basaltic textures including subophitic, phyric, cumulate (fine to coarse-grained varieties), variolitic, and shock melt. Phyric basalt: orthopyroxene phenocrysts, Fs56.4Wo3.0 (FeO/MnO = 34.5); groundmass augite, Fs35.6Wo34.2; plagioclase, An81.6. Coarse-grained cumulate: orthopyroxene, Fs43.9Wo1.9 (FeO/MnO = 37.3); exsolved pigeonite, Fs46.3Wo3.4; plagioclase, An94.9. Variolitic basalt: Fs59.0Wo2.9 (FeO/MnO = 35.3); subcalcic augite, Fs43.9Wo19.3; plagioclase, An76.5. Only very small amounts of ilmenite and no chromite were found in any rock type. All clasts and matrix are strongly shocked (S4-5, pyroxenes and plagioclase are mostly recrystallized); shock melt clasts are xenoliths, low weathering grade. Specimens: type specimen, 28 g, NAU; main mass, Birdsell.
Northwest Africa
Purchased 2004
Achondrite (cumulate eucrite)
A 2224 g complete stone that measures 189 mm x 112 mm x 82 mm at the widest points, with fresh crust was purchased in Erfoud, Morocco, Description and classification (T. Bunch and J. Wittke, NAU): cataclastic, cumulate eucrite; coarse-grained (plagioclase up to 7 mm and pyroxenes to 5 mm); zones of intense crushing with minor recrystallization; discontinuous melt veins and pockets. Plastic deformation and offset faulting in plagioclase; minor amounts of maskelynite; undulatory extinction, shock twinning, and reduced birefringence in pyroxenes; shock level, S3-5. Extensive development of albite, Carlsbad, and complex igneous twinning in plagioclase. Exsolution lamellae of subcalcic augite (Fs52.5Wo15.9) in inverted ferrohypersthene (Fs61.1Wo3.8) and separate grains of augite (Fs25.1Wo45.7), FeO/MnO of all pyroxenes between 32.2 and 34.8. Plagioclase, An90.8 and minor amounts of ilmenite and chromite, Cr/[Cr+Al] = 68-75. Low weathering grade. Specimens: type specimen, 23.1 g, NAU; main mass, D. Schultz.
Northwest Africa
Purchased 2004
Achondrite (eucrite)
A 509 g complete stone with light brown weathered crust was purchased in Tagounite. Morocco. Description and classification (T. Bunch and J. Wittke, NAU): highly shocked polymict, cumulate eucrite; fine- to medium-grained cumulate basalt clasts of irregular shapes and diffuse margins (shock level, S2-4) included within a mostly brecciated melt to recrystallized matrix (shock level, S3-6). Cumulate pyroxenes, Fs53.4Wo4.6 to Fs43.9Wo24.2; plagioclase, An90.1-94.6; chromite, Cr/[Cr+Al] = 64.3 -71.2; moderately weathered. Specimens: type sample, 23.1g, NAU; main mass, A. Hupe.
Northwest Africa
Found 2004
Achondrite (polymict eucrite)
History: A 3804 g crusted complete stone was purchased in Erfoud, Morocco, in 2004.
Petrography: (J. Wittke and T. Bunch, NAU) The specimen mostly consists of cumulate basalt clasts that range from coarse-grained (~2 mm) to very fine-grained (~0.1 mm) with less than 5 vol% of subophitic basalts observed. Cumulate basaltic clasts are unusually low in
ilmenite, chromite, and metal compared with other cumulate eucrites.
Composition: Despite the large range in grain size, pyroxene compositions show a rather narrow range: low-Ca pyroxenes (Fs59.1-62Wo3.2-3.8, pigeonite (Fs46.5-51Wo12.4-16.6, Ca-rich pyroxenes (Fs40-2.1Wo30.5-40., plagioclase (An89.4-92.
Classification: Achondrite (eucrite, polymict); low shock, minimal weathering.
Specimens: A 34 g type specimen is on deposit at NAU. E. Thompson holds the main mass.
Algeria
Find: 2004
Achondrite (polymict eucrite)
History and physical characteristics: A 43 g, partially crusted and lightly weathered stone was found in Algeria in 2004 and purchased in Rissani, Morocco in 2005.
Petrography: (T. Bunch and J. Wittke, NAU) polymict breccia that consists of a wide variety of basaltic clasts that include ophitic, subophitic, cumulate, and gabbroic with a limited shock level of S2-S3.
Mineral compositions: Ophitic and subophitic orthopyroxenes, Fs47-61Wo2.1-3.0, FeO/MnO = 26-31, pigeonites, Fs44-54Wo0.3-12.0. Gabbro opx = Fs41Wo3.2. Plagioclase is An84-94. Chromite, Cr/[Cr+Al] = 0.78-0.88.
Classification: Polymict eucrite breccia.
Type specimen: A total of 9.2 g is on deposit at PSF. Mr. Matt Morgan holds the main mass.
Northwest Africa
Purchased 2004
Achondrite (eucrite, polymict breccia)
History: Four partial stones weighing a total of 458 g were purchased in Erfoud, Morocco, in October 2004.
Petrography and Geochemistry: (J. Wittke and T. Bunch, NAU) The sample contains an assortment of cumulate (maximum grain size = 1.8 mm), subophitic (maximum grain size = 0.2 mm), and shock-melted to crystallized basalts. Cumulate basalts: Pyroxenes (Fs49.3Wo2.8; Fs38.8Wo13.9; Fs48.5Wo21.2; FeO/MnO for all = 31-40), plagioclase (An87); chromite (Cr/[Cr+Al] = 0.77). Subophitic basalts: Pyroxenes (Fs39.1-45.6Wo8.7-15.8; FeO/MnO = 30-36), plagioclase (An89) ,chromite (Cr/[Cr+Al] = 0.87).
Classification: Achondrite (eucrite, polymict breccia); low to high shock, minimal weathering.
Specimens: A 46 g type specimen is on deposit at NAU. Olsen holds the main mass.
Northwest Africa
Find: 2004
Achondrite (eucrite, polymict breccia)
History: A 141 g stone was purchased in Erfoud, Morocco, in October 2004.
Petrography: (T. Bunch and J. Wittke, NAU) A brecciated cumulate host (grain size up to 2.1 mm) with clasts of subophitic (maximum grain size, 0.12 mm) and recrystallized granular (average grain size, 0.03 mm) basalts.
Geochemistry: All analyzed lithologies are very similar in pyroxene and plagioclase composition. Orthopyroxenes (Fs62-64.1Wo2.1-2.8), Ca-rich pyroxene (Fs27-31.1Wo43.7-44.8), and plagioclase (An87.8-89.7). Pigeonite exsolution lamellae are too thin to analyze; cumulate contains Cr-rich ilmenite (Cr2O3 = 15.1 wt%) and Cr-poor ilmenite. Other lithologies contain chromite of similar composition, Cr/[Cr+Al] = 0.85, and minor ilmenite.
Classification: Achondrite (eucrite, polymict breccia); low shock (no maskelynite), minimal weathering.
Specimens: A 25 g type specimen is on deposit at NAU. Birdsell holds the main mass.
Morocco
Purchased 2005
Achondrite (eucrite, monomict melt breccia)
History: A 100.2 g complete stone was purchased in Erfoud, Morocco, in May 2005.
Petrography: (J. Wittke and T. Bunch, NAU) Specimen contains medium-grained (<2 mm), centimeter-size, cumulate basalt clasts set in a microbreccia melt matrix. Clasts are moderately shocked with partial maskelynization of plagioclase and mechanical twinning, optical mosaicism and reduced birefringence in pyroxenes. The dark matrix is a flow mixture of FeO-rich glasses, very small cumulate basalt fragments, and patches of quench-textured microbasalt.
Geochemistry: Monomict cumulate basalt: host Ca-poor pyroxene (Fs55.4-57.8Wo5.1-2.9), FeO/MnO = 28; exsolved augite (Fs24.2Wo44.7), FeO/MnO = 36; plagioclase/maskelynite (An90.8); chromite Cr/[Cr+Al] = 0.86.
Classification: Achondrite (eucrite, monomict melt breccia); moderate shock, minimal weathering.
Specimens: A 21 g type specimen is deposited at NAU. Birdsell holds the main mass.
Morocco
Purchased 2005
Achondrite (eucrite, monomict breccia)
History: Three paired partial stones weighing a total of 122 g were purchased in Erfoud, Morocco, in April 2005.
Petrography: (T. Bunch and J. Wittke, NAU) Cataclastic cumulate basalt that shows a remarkable range of shock features that include alternating bands of cataclastic and melt flows, mylonite-like swirls and lenticular masses, and rounded, finely crushed breccia clasts that are separated by dark, glassy to cryptocrystalline bands.
Geochemistry: Host: orthopyroxene (Fs59.3-62.7Wo3.1-1.9; FeO/MnO = 31), exsolved augite (Fs26.8-27.8Wo43-42.1; FeO/MnO = 28), plagioclase (An92); chromite (Cr/[Cr+Al] = 0.88).
Classification: Achondrite (eucrite monomict breccia) with moderate to high degree of shock and low degree of weathering.
Specimens: A 21.1 g type specimen is on deposit at NAU. Birdsell holds the main mass.
Morocco
Find: 2005
Achondrite (eucrite, polymict)
History and physical characteristics: A 1365 g stone was purchased from a dealer in Erfoud, Morocco in 2006. The stone has moderately fresh fusion crust that covers most of the surface.
Petrography (T. Bunch and J. Wittke, NAU): Contains medium to fine-grained cumulate, subophitic, and shock-melted clasts set in a fresh, light to dark gray matrix of cataclastic material. One medium-grained cumulate lithology has an unusual amount of tiny metal grains evenly distributed throughout the clasts.
Geochemistry: Medium-grained cumulate orthopyroxene = Fs41-50.9Wo2.0-4.8 (FeO/MnO = 30.5-34); pigeonite = Fs37.8Wo12.6; plagioclase, An90.3; chromite, Cr/(Al+Cr) = 0.88; and metal has 2.2 wt% Ni.
Classification: Achondrite (eucrite, polymict).
Type Specimen: A total of 29 g is on deposit at NAU. K. Davis holds the main mass.
Algeria
Found 2006
Achondrite (eucrite)
History: The main-mass holders purchased the stone in Erfoud, Morocco in September 2006.
Physical characteristics: A single, complete stone of 4602 g with partial, moderately weathered fusion crust.
Petrography J. Wittke and T.
Bunch, NAU): Microgranular (pyroxenes < 0.05 mm; plagioclase < 0.1 mm) with rare pyroxene splays and megacrysts of plagioclase and pyroxene (up to 0.6 mm in longest dimension), At least two brecciation episodes (breccia-in-breccia)
are crosscut by shock melt injection veins. These melt veins have bulk major- and minor-element compositions consistent with typical eucrite bulk compositions. The stone contains orthopyroxene, augite, plagioclase, chromite, and troilite.
Geochemistry: Orthopyroxene, Fs61Wo2.1; augite, Fs42.3Wo37.8; chromite, Cr/[Cr+Al] = 0.81;
plagioclase, An92.3. EMP broad beam analysis of the shock melt glass is: Si = 22.75; Al = 8.7; Ca = 9.45, Ti = 0.45; Cr = 0.21; Fe = 12.4; Mg = 3.1; Mn = 0.3 (all wt%).
Classification: Achondrite (eucrite); S5; minimal weathering.
Type specimens: A total of 20.1 g and one thin section are on deposit at NAU. Farmer and Strope hold the main mass.
Northwest Africa
Found 2003
Achondrite (eucrite, polymict)
A 131 g stone was purchased in Morocco in Morocco, September 2003. Description and classification (T. Bunch and J. Wittke, NAU): dark to medium gray, brecciated eucrite that essentially contains medium to fine-grained cumulate eucrites. Highly shocked (S4-5): maskelynite and solid state recrystallization of plagioclase; reduced birefringence and recrystallization of pyroxenes; localized melt pockets. Dominate basalt lithology: low-Ca pyroxenes, Fs56.1-59.3Wo1.4-1.8 (Fe/Mn = 32-34.8), exsolution lamellae (Fs35.Wo28.8); augite, Fs23.5Wo43.1. Plagioclase is unusually sodic and slightly zoned, An68-70Or8.2-2.0; chromite, Cr/[Cr+Al] = 81 and Fe/(Fe+Mg) = 98.7; low Ni metal (0.32 wt% Ni and 0.52 wt% Co). Lightly weathered. Specimens: 21.1 g, NAU; main mass, Hupé.
Northwest Africa
2003
Achondrite (eucrite)
A single, partially crusted 132.1 g stone was purchased in Erfoud in February 2004. Description and classification (T. Bunch and J. Wittke, NAU): light to medium gray, microcrystalline (< 0.3 mm, mean grain size of ~0.2 mm), subophitic basalt; fractured with interclast granulation and recrystallization; minor clast rotation. Pigeonite, Fs56.3-63.5Wo16.1-6.5with submicron exsolution lamellae; Ca-pyroxene, Fs49Wo27.9; plagioclase, An90.8, chromite, Cr/[Cr+Al] = 92.7, troilite, ilmenite, metal, and silica. Shock level, S2-3; low grade weathering. Specimens: 20.1, NAU; main mass, Oakes.
Algeria
Find: 2005
Achondrite (eucrite monomict breccia)
History: A 364 g stone was found in Southern Algeria and purchased in Erfoud, Morocco, in November 2005.
Physical characteristics: Primary and secondary ablation crust partially cover the stone.
Petrography (J. Wittke and T. Bunch, NAU): monomict breccia with subrounded, cm-sized clasts of subophitic basalt set in a cataclastic matrix. Thin bladed plagioclase up to 5 mm in length encloses granular anhedral pyroxenes, chromite, and ilmenite. Sparse areas of ophitic-textured basalt also occur.
Geochemistry: Orthopyroxene host is Fs59-63.7Wo3.3-4.1, augite exsolution lamellae are Fs26.1-28.9Wo44.2, plagioclase is An87 and chromite Cr/[Cr+Al] = 0.83-0.88.
Classification: Achondrite (eucrite monomict breccia). Shock level is S2 and the weathering grade is very low.
Type specimens: A total of 30 g and one thin section are on deposit at NAU. Thompson holds the main mass.
Northwest Africa
Find 2006
Achondrite (cumulate eucrite)
History: A stone was found by an individual while tending to a goatherd and purchased in Rissani in July 2006.
Physical characteristics: A complete and elongated 19 g stone with fresh fusion crust.
Petrography (J. Wittke and T. Bunch, NAU): Fine- to medium-grain-size, monomict cumulate eucrite with plastic
flow features. Clusters of interpenetrating plagioclase crystals that display prominent albite twinning, enclose pyroxenes.
Geochemistry; Orthopyroxene, Fs59.7-61Wo3.8; FeO/MnO = 31-33, n = 15); pigeonite, Fs52.1-55Wo6.9-11.2; ferroaugite, Fs47.8Wo27.2; plagioclase, An89-92, chromite, Cr/[Cr+Al] = 0.69.
Classification: Achondrite, (eucrite, cumulate, monomict breccia); minimal shock and weathering.
Type specimens: A total of 4.1 g and one thin section are on deposit at NAU. The main mass holder is anonymous.
Algeria
Find: 2006
Achondrite (basaltic eucrite, monomict breccia)
History and physical characteristics: Found in Algeria and purchased from a dealer in Erfoud, Morocco by S. Turecki in 2006. The single 168 g stone has a fresh, black fusion crust.
Petrography: (J. Wittke and T. Bunch, NAU) Fine-grained (< 0.35 mm), subophitic basalt breccia, dominated by sub-rounded clasts that are set in a cataclastic matrix. Minimal weathering and low to moderate shock level.
Mineral compositions: Pigeonite (Fe54.7-59.4Wo4.4-7.3; FeO/MnO = 31-34), augite (Fs38Wo46.5), plagioclase (An94.3), chromite (Cr/[Cr+Al] = 0.85), with minor ilmenite and silica.
Classification: Achondrite (basaltic eucritic, monomict breccia)
Type specimen: A 20 g sample is on deposit at NAU. Mr. S. Turecki is the main mass holder.
Northwest Africa
Find: 2007
Achondrite (eucrite, monomict breccia)
History and physical characteristics: A 97 g fully crusted, fresh stone was purchased in Tucson at the Tucson Gem and Mineral Show in January 2007.
Petrography (J. Wittke and T. Bunch, NAU): Highly shocked monomict, basaltic eucrite breccia. Partially recrystallized with maskelynite and plagioclase glass, mosaic to recrystallized pyroxenes, and dark, shock-melt clasts.
Mineral compositions: Pigeonite host, Fs56.6Wo5.7; augite lamellae, Fs33.2Wo32.6. Plagioclase is An90.8.
Classification: Achondrite (eucrite, monomict breccia).
Type specimen: 19.7 g are on deposit at NAU. The main mass holder is anonymous.
Northwest Africa
Find: 2006
Achondrite (eucrite, polymict)
History and physical characteristics: A 226 g complete stone with moderately fresh fusion crust was purchased in Tucson at the Tucson Gem and Mineral Show in January 2007.
Petrograpy (J. Wittke and T. Bunch, NAU): A brecciated polymict eucrite with cataclastic flow veins and partially recrystallized matrix. Consists of cumulate, subophitic, and ophitic basalt clasts. A portion of the plagioclase was converted to maskelynite by shock and most pyroxenes are shock-decorated. Shock level is S4 and the weathering grade is very low.
Mineral compositions: subophitic orthopyroxene host, Fs56.8Wo3.6 (FeO/MnO = 30-32); exsolution lamellae, Fs29Wo39.5. Pigeonite is Fs56.7Wo8.8 and plagioclase is An90.2-94.5. Minor minerals include silica, chromite, ilmenite, and FeS.
Classification: Achondrite (eucrite, polymict).
Type specimen: A total of 23.1 g is on deposit at NAU. The main mass holder is anonymous.
Northwest Africa
Find: 2006
Achondrite (eucrite, monomict)
History and physical characteristics: A 38 g fully crusted stone with moderately fresh fusion crust was purchased at the Denver Gem and Mineral in September 2006.
Petrography (T. Bunch and J. Wittke, NAU): This stone is a monomict, eucrite basalt with granoblastic texture. Most of the sample was recrystallized into an assemblage of very fine-grained polygons (< 0.03 mm). Vestiges of the original texture show a fabric of divergent plagioclase laths and interstitial pyroxenes. Maximum length of the plagioclase laths is < 0.4 mm. Early shock effects were probably annealed out during recrystallization. The last shock episode is S2 and weathering effects are minimal.
Mineral compositions: (relict and recrystallized minerals are essentially the same). Orthopyroxene, Fs60.5Wo2.1 (FeO/MnO = 32); augite, Fs37.4Wo35.5; plagioclase, An93; chromite Cr/[Cr+Al] = 0.84.
Classification: Achondrite (eucrite. monomict).
Type specimen: A total of 7.7 g is on deposit at NAU. The main mass holder is anonymous.
Northwest Africa
Find: 2006
Achondrite (eucrite, monomict cumulate)
History and physical characteristics: A 154 g, partial stone with moderately fresh fusion crust, was purchased at the Denver Gem and Mineral Show in September 2006.
Petrography (J. Wittke and T. Bunch, NAU): A monomict cumulate eucrite with breccia-within-breccia texture. Clasts tend to be subrounded and contain orthopyroxenes that are commonly devoid of exsolved Ca-pyroxenes. Plagioclase contains micros-sized oriented pyroxene inclusions. Shock level is S3-S4 and the weathering grade is low.
Mineral compositions: Orthopyroxene, Fs46.7-52Wo2.2-3.1 (FeO/MnO =32); augite, Fs36.4Wo44.7; plagioclase An88-91.1.
Classification: Achondrite (eucrite, monomict cumulate).
Type specimen: A total of 21.4 g is on deposit at NAU. The main mass holder is anonymous.
Algeria
Find: 2006
Achondrite (eucrite, polymict)
History and physical characteristics: A very fresh, partial 50 g stone with bubbly fusion crust was purchased in Erfoud, Morocco in 2007. Large areas crushed to white, powdery rock flour.
Petrography (J. Wittke and T. Bunch, NAU): Fine-grained (few clasts exceed two mm) polymict breccia of cumulate, ophitic, subophitic basalts and shock-melt clasts set in a cataclastic matrix. No oxidation of rare metal grains, equivalent to W0/1. Shock level of clasts ranges from S2 to S6.
Geochemistry: Ophitic basalt: orthopyroxene host, Fs57.4Wo3.2 (FeO/MnO = 32; exsolution lamellae, Fs32.6Wo34.8; Plagioclase, An92.7; chromite, Cr/(Al+Cr) = 0.86.
Classification: Achondrite (eucrite, polymict).
Type sample: A total of 10 g are on deposit at NAU. Cimala holds the main mass.
Northwest Africa
Find: 2007
Achondrite (eucrite, monomict breccia)
History and physical characteristics: A single 29 g stone was purchased in Erfoud Morocco in August 2007. Some fusion crust remains, although much has been wind ablated away leaving a translucent surface, chemical weathering is minor.
Petrography (T. Bunch and J. Wittke, NAU): Monomict cumulate basalt breccia that is highly shocked. Plagioclase is completely recrytallized. Pyroxenes are partially recrystallized, unrecrystallized pyroxenes have reduced birefringence, shock lamellae, and are darkened by shock decorations. Unusual amount of metal for a eucrite (vol% = 4). Sparse, but large chromite grains (0.3 to 1.1 mm) are present. Weathering grade is low with some staining around metal grains.
Mineral compositions: Fs45.7Wo1.9 (FeO/MnO = 28); lamellae, Fs8.2Wo14.8; augite, Fs16.6Wo46.1. Plagioclase, An87.8, chromite Cr/[Cr+Al] = 0.81, and metal Ni = 0.87 wt%.
Classification: Achondrite (eucrite, monomict breccia).
Type specimen: A total of 5.9 g is on deposit at NAU. Mr. M. Cimala holds the main mass.
Northwest Africa
Find: 2007
Achondrite (eucrite, monomict breccia)
History and physical characteristics: A single 188 g single stone was purchased in Erfoud, Morocco in August 2007. The fusion crust is very fresh with only minor desert ablation and staining.
Petrography (J. Wittke and T. Bunch, NAU): Monomict eucrite breccia that consists of subophitic decorated basalt clasts set in a crushed matrix. The interior is very fresh and the shock level is moderate.
Mineral composition: Orthopyroxene host pyroxene is Fs62Wo8.3, lamellae are Fs55.8Wo8.3, augite is Fs28.4Wo42. Plagioclase is An88.8 and chromite Cr/[Cr+Al] = 0.83.
Classification: Achondrite (eucrite, monomict breccia).
Type specimen: A total of 20 g is on deposit at NAU. The main mass holder is Mr. M. Cimala.
Algeria
Find: 2007
Achondrite (eucrite, polymict)
History and physical characteristics: A 366 g stone was purchased in Erfoud, Morocco by M. Cimala in 2007. The stone is partially covered by wind-ablated fusion crust.
Petrography (J. Wittke and T. Bunch, NAU): Polymict breccia that consists of fine to medium grained ophitic to subophitic basalts. Weathering grade is low, slight staining of metal grains. Shock level is low to medium in the various basaltic clasts.
Geochemistry: Medium grained clasts: host orthopyroxene, Fs59.3Wo4.3 (FeO/MnO = 30); exsolution lamellae, Fs30.9Wo38.4; pigeonite, Fs48.5Wo8.7; plagioclase, An91.7; chromite, Cr/(Al+Cr) = 0.84.
Classification: Achondrite (eucrite, polymict).
Type specimen: A total of 20.4 g are on deposit at NAU. Cimala holds the main mass.
Northwest Africa
Find: 2007
Achondrite (eucrite, shock melt breccia)
History and Physical Characteristics: A very dark 76 g stone with little fusion crust was found in Algeria and purchased in Erfoud in October 2007.
Petrography (T. Bunch and J Wittke, NAU): Large, partially melted cumulate basalt clasts are set in a shock melt flow that consists of partially melted basalt fragments and quenched, subophitic microbasalt. The large clasts and fragments are subrounded and show margin resorption. The overall shock level is medium to high (S3-5).
Mineral compositions: Cumulate orthopyroxene is Fs54.3-60Wo3.3-4.9; exsolved augite is Fs25.9Wo45. Plagioclase is An92.9.
Classification: Achondrite (eucrite, shock melt breccia).
Type specimen: A total of 15.4 g is on deposit at NAU. Cimala is the main mass holder.
| ID | Location | Date | Mass (g) | State | Fa | Fs | Comments |
|---|---|---|---|---|---|---|---|
| NWA 2655 | Erfoud, Morocco | 2004 | 257 | S4-5 | - | 57 & 34.8 | paired with NWA 2366 |