Shergottites


Download: NWA-2800 Poster PDF (large file) - presented at 39th Lunar and Planetary Science Conference (2008)

Northwest Africa 2046

Algeria
Purchased 2003 September
Martian meteorite (basaltic shergottite)

NWA 2046

A 63g complete and partially crusted stone found near Lakhbi, Algeria was purchased from a Moroccan dealer in 2003 September by M. Farmer (Farmer). The ellipsoidal stone has an average width of 30 mm, with a 1 to 3 mm thick weathering rind; the interior is very fresh and unweathered. Classification and mineralogy (J. Wittke and T. Bunch, NAU; A. Irving and S. Kuehner, UWS): olivine-orthopyroxene-phyric basaltic rock. Subhedral to euhedral, dark brown olivine phenocrysts (up to 2.2 mm long) are strongly zoned from cores of Fa15.7 to rims of Fa47.9, and subhedral to euhedral, prismatic orthopyroxene phenocrysts (up to 2.1 mm long) have cores as magnesian as Fs17.7Wo2.5, surrounded by irregularly zoned mantles with both pigeonite and augite, and pigeonite rims as ferroan as Fs39.0Wo12.5. The groundmass consists mainly of zoned pigeonite (Fs30Wo6.5 to Fs40Wo13) intergrown with maskelynite (zoned from cores of Ab25.5Or0.1 to rims of Ab36.5Or1.1) and small grains of relatively ferroan olivine (Fa47.6-58.1). Accessory minerals include Ti-chromite (Al/(Al+Cr) = 13.8-28.3), chromite, ilmenite, Cr-ulvöspinel, pyrrhotite (commonly in parallel growth with ilmenite), merrillite, rare chlorapatite, and rare fayalite (which occurs as a reaction rim on groundmass pigeonite in contact with ilmenite or pyrrhotite). Trapped melt inclusions in olivine contain aluminous diopside, amphibole(?), pleonaste, chromite, merrillite and glass. Large, prismatic orthopyroxene phenocrysts exhibit preferred orientation suggestive of magmatic flow and/or crystal accumulation, possibly in a subsurface dike; olivine phenocrysts are weakly oriented and tend to occur in clusters. Textures and mineral compositions are similar to those in olivine-orthopyroxene-phyric shergottite NWA 1195, but the olivine cores in NWA 2046 are more magnesian (Irving et al., 2004). Specimens: type specimen, 12.2 g, and one polished thin section, NAU; one polished thin section, UWS; main mass, Strope.

NWA 2046

NWA 2046. False-color backscattered electron image showing strong compositional zoning in subhedral olivine phenocrysts (green to red to yellow), orthopyroxene microphenocrysts (blue), and groundmass pigeonite (green), maskelynite (black), chromite and ilmenite (both white). Photo © Anthony Irving and Scott Kuehner, 2004

NWA 2046. False-color backscattered electron image showing prismatic orthopyroxene phenocryst and microphenocrysts (blue) mantled by pigeonite (green), with groundmass pigeonite (red and yellow), maskelynite (black), chromite and ulvöspinel (both white). Photo © Anthony Irving and Scott Kuehner, 2004.

NWA 2046. Pyroxene and olivine compositions.

References

A. J. Irving, T. E. Bunch, S. M. Kuehner, & J. H. Wittke, 2004, Petrology of primitive olivine-orthopyroxene-phyric shergottites NWA 2046 and NWA 1195: Analogies with terrestrial boninites and implications for partial melting of hydrous Martian mantle. Abstr. 35th Lunar Planet. Sci. Conf., #1444.

Another web page: http://www2.jpl.nasa.gov/snc/nwa2046.html


Northwest Africa 2373

Northwest Africa
Purchased 2004 August
Martian (basaltic shergottite)

NWA 2373. Long dimension approximately 3 cm. © John and Dawn Birdsell, 2005

An 18.1 g stone was purchased in Erfoud Morocco. Yellow brown with desert ablation/varnish surface only, no fusion crust. Description and classification (T. Bunch and J. Wittke, NAU): olivine phenocrysts (<1.25 mm in longest dimension) set in a fine-grained groundmass (<0.1 mm) of pigeonite, maskelynite, chromite, Ti-magnetite, augite, chlorapatite and sulfide. Olivine has cores of Fa30.7 (FeO/MnO = 51.9) and rims of Fa50.3 (FeO/MnO = 53.3) and contains micron to submicron inclusions of chromite, glass, and barite. One large olivine grain, which may be a xenocryst, is different from the rest with a core of Fa29.1 (FeO/MnO = 43) and more abundant tiny inclusions. The wide (0.2 to 0.4 mm), inclusion-free mantle on this grain is Fa32.3 (FeO/MnO = 39.2). Pigeonite is zoned from Fs29.4Wo8.4 to Fs36.4 Wo14.1 (FeO/MnO = 28); augite is Fs21.8 Wo29.1. Maskelynite is slightly zoned with a compositional average of An52.1Or2.1. Chromite, Cr/(Cr+Al) = 87, fe# = 90.4. Overall texture, mineral content and mineral compositions strongly suggest that this stone is paired with NWA 1068. Specimens: type specimen, 3.7 g and one thin section, NAU; main mass, Birdsell.

Another web page: http://www2.jpl.nasa.gov/snc/nwa2373.html


Northwest Africa 2626

Algeria
Purchased 2004 November
Martian (basaltic shergottite)

NWA 2626. Long dimension approximately 3 cm. © Michael Farmer, 2005

NWA 2626. Cut slices of the type specimen showing dark olivine phenocrysts, glass veinlets and thin weathering rind. Photo © Ted Bunch, 2005

A 31.07 g completely crusted stone, found at an unknown site in Algeria, was purchased from a Moroccan dealer in 2004 November by M. Farmer (Farmer). The ellipsoidal stone measured 28.9 mm by 16 mm by ~15 mm, and has a 1 to 2 mm thick weathering rind; the dark greenish interior is very fresh and unweathered, but contains thin, glass-rich veinlets and pockets, presumably produced by shock. Classification and mineralogy (J. Wittke and T. Bunch, NAU; A. Irving and S. Kuehner, UWS): olivine-orthopyroxene-phyric basaltic rock composed of euhedral to subhedral olivine phenocrysts and preferentially-oriented, prismatic low-Ca pyroxene phenocrysts in a groundmass of zoned pigeonite (Fs26.4Wo12.4 to Fs34.1Wo12.4), maskelynite (An66.0-71.0Or0.4), olivine (Fa43.6-47.3), Ti-chromite (Cr/(Cr+Al) = 0.72-0.79; 9.2-19.8 wt% TiO2), chromite (Cr/(Cr+Al) = 0.71-0.86; 0.7-2.0 wt% TiO2), merrillite, ilmenite, ulvöspinel and pyrrhotite. Olivine phenocrysts are zoned from Fa16.7 cores to Fa43.3 rims, and pyroxene phenocrysts have irregular cores of orthopyroxene (as magnesian as Fs17.9Wo2.4, with ~0.03 wt% TiO2 and ~0.4 wt% Al2O3) mantled by pigeonite (Fs25.4Wo4.4 to Fs37.0Wo12.7) with minor subcalcic augite (Fs21.7-24.0Wo30.8-31.1). Although textures and mineral compositions are similar to those in olivine-orthopyroxene-phyric shergottites NWA 1195 and NWA 2046 (Irving et al., 2004), none of these specimens seem to be terrestrially paired. Both olivine and pyroxene core compositions in NWA 2626 are less magnesian than those in NWA 2046, yet zoned to less ferroan rim and groundmass compositions (Irving et al., 2005), and NWA 1195 is a complete stone from a different, well-documented location near Safsaf, Morocco (Russell et al., 2002). Specimens: type specimen, 6.4 g, and one polished thin section, NAU; one polished thin section, UWS; main mass, Anonymous.

NWA 2626. Thin section in plane-polarized light (approximately 12 mm across). showing olivine phenocrysts (yellow-brown) and smaller, prismatic orthopyroxene phenocrysts (pale brown) in a finer grained groundmass of mainly pigeonite (pale brown) and maskelynite (white). Note the prominent dark brown, shock-produced glassy veinlets. Photo © Ted Bunch, 2005

NWA 2626. Portion of the thin section above in partially cross-polarized light (approximately 10 mm across). Several orthopyroxene phenocrysts are visible as prismatic grains with prominent twinning. © Ted Bunch, 2005.

NWA 2626. False-color backscattered electron image showing strong compositional zoning in subhedral olivine phenocrysts (green to red to yellow), orthopyroxene microphenocrysts (blue), and groundmass pigeonite (green), maskelynite (black), chromite and ilmenite (both white). Photo © Anthony Irving and Scott Kuehner, 2005

NWA 2626. False-color backscattered electron image showing prismatic orthopyroxene phenocryst and microphenocrysts (blue) mantled by pigeonite (green), with groundmass pigeonite (red and yellow), maskelynite (black), chromite and ulvöspinel (both white). Photo © Anthony Irving and Scott Kuehner, 2005.

References

A. J. Irving, T. E. Bunch, S. M. Kuehner & J. H. Wittke (2004) Petrology of primitive olivine-orthopyroxene-phyric shergottites NWA 2046 and NWA 1195: Analogies with terrestrial boninites and implications for partial melting of hydrous Martian mantle. Abstr. 35th Lunar Planet. Sci. Conf., #1444.

A.J. Irving, T. E. Bunch, J. H. Wittke & S. M. Kuehner (2005) Olivine-orthopyroxene-phyric shergottites NWA 2626 and DaG 476: The Tharsis connection. Abstr. 36th Lunar Planet. Sci. Conf., #1229.


Northwest Africa 2646

Algeria or Morocco
Found 2004 December
Martian (plagioclase-olivine clinopyroxenite)

NWA 2646. Main mass. Sample width is 1.7 cm. Photo © Oakes 2006

History: A 9.3 g, broken stone (allegedly part of a larger specimen found at an unknown site in Algeria or Morocco) was purchased from a Moroccan dealer in December 2004 for N. Oakes.
Petrography and Geochemistry: (T. Bunch and J. Wittke, NAU; A. Irving and S. Kuehner, UWS) The specimen is relatively coarse-grained and has an overall gray color, but grain surfaces have a thin whitish coating. It is modally heterogeneous and is composed of ~40.7 % pigeonite, ~24.3 % augite, ~21.6 % olivine, and ~11.4 % maskelynite, with 2 % chromite, ilmenite, merrillite, and pyrrhotite. Euhedral to subhedral chromite (Cr/(Cr+Al) = 0.869, Mg/(Mg+Fe) = 0.12) and augite (Fs19-23Wo26-36; FeO/MnO = 22-27; Cr2O3 = 0.6, Al2O3 = 2.2 [both wt%]) appear to have crystallized first, followed by subhedral to anhedral olivine (Fa38-44; FeO/MnO = 35-56). These are poikilitically enclosed in large oikocrysts of pigeonite (Fs24.4Wo5.7 zoned to Fs34.4Wo12.1; FeO/MnO = 26-32); augite and olivine chadacrysts tend to be clustered. Laths of plagioclase (now maskelynite, An58.4-60.7Or0.9), some in clusters, occur interstitially to pigeonite grains. All maskelynite grains are rimmed by zones up to 40 μm in width consisting of a mixture of fine grained calcite, hydrous Al-rich silicate (possibly kaolinite), and very minor calcium chloride, which appear to be replacing the primary feldspar. This specimen has affinities to the six recognized "lherzolitic shergottites," but differs from them in having a higher abundance of plagioclase and more ferroan mafic mineral compositions.
Classification: Achondrite (Martian, plagioclase-olivine clinopyroxenite); minimal weathering.
Specimens: A 3.4 g type specimen and one polished thin section are on deposit at NAU. One polished mount is on deposit at UWS. N. Oakes holds the main mass.

NWA 2646. Backscattered electron image showing overall texture; minerals in order of decreasing gray: maskelynite, pigeonite, augite and olivine, chromite and ilmenite (both white). Scale bar at right is 1 mm. Photo © J. H. Wittke 2006.

NWA 2646. Typical ophitic to granular texture that shows pigeonite, augite, olivine, maskelynite (plagioclase) and chromite. Image width is 6 mm. Photo © T E Bunch 2006.

NWA 2646. Large, compositionally zoned pigeonite grain that poikilitically encloses augite and olivine. Image width is 6 mm. Photo © T E Bunch 2006.

Reference

Bunch, T. E., Irving, A. J., Wittke, J. H. & Kuehner, S. M., 2005, NWA 2646: A Martian plagioclase-olivine clinopyroxenite akin to "lherzolitic shergottites". Abstr. 68th Met. Soc. Mtg., #5209.


Northwest Africa 2800

Morocco
Find: July 2007
Achondrite (Martian, basaltic shergottite)

History and Physical characteristics: A 686 g stone was purchased in Morocco in July 2007 by an anonymous buyer. NWA 2800 is a complete and lightly weathered stone with significant desert ablation that has eroded most of the fusion crust and imparted a dull to shiny sheen to the surface.
Petrography: (T. Bunch and J. Wittke, NAU: A. Irving, UWS) This basaltic shergottite is very coarse-grained with ophitic to mostly subophitic texture with orientated elongated crystals together with prominent patches of pyroxferroite breakdown phases. Maskelynite long dimensions reach 6 mm and several pyroxene crystals are blade-like with dimensions of 7.3 x 0.4 mm. Pigeonite and augite show prominent {100} simple twinning, extensive sector compositional zoning and exsolution lamellae, in addition to shock lamellae. Patches of possible decomposed pyroxferroite contain symplectites of fayalite, silica and Fe-rich pyroxene with associated Cl-apatite, merrillite, ulvöspinel, ilmenite with included pyrrhotite, silica needles (up to 2 mm in length), and silica-rich glasses. Interstitial pockets of late-stage residuum ("chaotic" zones), which are typically contiguous to patches of pyroxferroite decomposition, consist of K-feldspar and plagioclase hopper and acicular crystals, clusters of anhedral fayalite grains, solitary euhedral fayalite crystals, silica crystals, and graphic intergrowths of silica and plagioclase, all of which are set in an inhomogeneous glassy mesostasis. Modal analyses in vol%: plagioclase (maskelynite) = 47; pyroxenes = 39; decomposed patches = 10; late stage residuum = 2 and oxides = 2.
Mineral compositions: Main body pigeonites are zoned (Fs38.7-60.1Wo10.2-19.1; FeO/MnO = 33-41). Augite and subcalcic augite are zoned (Fs26.3-69.1Wo35.3-23.3). Maskelynite shows a wide range of cation deficiency in stoichiometry in all analyses (An55.5Or0.6-An72.3Or3.8; [n = 25]). Plagioclase (An73.9Or5.6) in graphic intergrowths and K-feldspar (Or59Ab31) hopper crystals. Symplectite fayalite (Fa94.7) and solitary fayalite (Fa89.3; CaO = 0.35 wt%) in chaotic zones.
Classification: Achondrite (Martian, basaltic shergottite). NWA 2800 is very similar in texture, mineral content, and phase compositions to the Los Angeles basaltic shergottite.
Type specimens: A total of 20.3 g is on deposit at NAU. The main mass holder is anonymous.


Northwest Africa 2969

Northwest Africa
Purchased 2005 August
Martian (olivine-phyric shergottite)

History: Several dozen, very small stones <15 mm in longest dimension, for a total weight of 11.7 g, were collected in the general area where shergottites NWA 1068/1110/2373 were found.
Petrography (T. Bunch and J. Wittke, NAU): subangular to subrounded complete to partial stones with little or no fusion crust. Olivine phenocrysts (<1.5 mm in longest dimension) set in a fine-grained groundmass of pigeonite, maskelynite, chromite, Ti-magnetite, augite, chlorapatite and sulfide.
Mineralogy: Olivine has cores of Fa31.7 (FeO/MnO = 50-54.5) and rims of Fa50.3 (FeO/MnO = 54-57). Pigeonite is zoned from Fs36.3Wo8.1 to Fs44Wo12.7 (FeO/MnO = 26); augite is Fs22.5Wo28.4; maskelynite, An53.1Or2.2. Chromite, Cr/(Cr+Al) = 0.87, Fe/(Fe+Mg) = 0.90. Minor phases include zincian troilite, silica, pentlandite, and Cr-ulvöspinel.
Classification: olivine-phyric shergottite. Overall texture, mineral content and mineral compositions, together with the find site location, strongly suggest that these stones are paired with NWA 1068/1110/2373.
Specimens: type specimen, 4.3 g and one thin section, NAU; main mass, Birdsell.


Northwest Africa 2975

Algeria
Found 2005
Achondrite (Martian, basaltic shergottite)

NWA 2975. Image © T. E. Bunch, 2009.

History: A minimally weathered fully encrusted whole stone of 70.1 g was purchased in Erfoud, Morocco, by M. Farmer in November 2005.
Petrography: (T. Bunch and J. Wittke, NAU; A. Irving, UWS) A medium-grained (<3.1 mm greatest dimension) basaltic shergottite that consists of ~57.3 vol% augite and pigeonite pyroxenes, and 38.3 vol% plagioclase (present as shockformed maskelynite and glasses) with minor opaques (2.7 vol%) and phosphates (1.7 vol%) arranged in a weakly foliated subophitic to granular texture. Accessory phases include ulvöspinel, ilmenite, chlorapatite, merrillite, pyrrhotite, Si-Al-Na-K-rich glasses, and baddeleyite. Vesicular black glass veins (<3 mm in width) and pockets (up to 6 mm) are prominent.
Geochemistry: Pigeonite (Fs35.2-57.6Wo12.6-16.5; FeO/MnO = 28-38) and augite (Fs27.2-41.5Wo30.8-35.2) show mottled compositional zoning. Fe-rich margins of pigeonite contain very thin (0.2-0.5 μm) orthopyroxene exsolution lamellae. Maskelynite is compositionally homogeneous An55Or1.8 in contrast to mesostasis maskelynite (An48-60Or9.2) and glasses. Melt inclusions (15-60 μm, longest dimension) in ulvöspinel have rims of Fe-rich pigeonite (Fs73.5Wo5.8), merrillite, and pyrrhotite; cores are Si-Al-K-Na-rich glass. Bulk composition: Calculated average bulk composition based on analyzed phases and their modes of three melt inclusions is: SiO2 = 70.2, Al2O3 = 8.5, TiO2 = 0.8, FeO = 2.1, MnO = 0.2, MgO = 2.35, CaO = 3.5, Na2O = 0.95, K2O = 2.1, and P2O5 = 2.8 (all wt%) with trace amounts of NiO, CoO, and S. One melt inclusion contains only fayalite (Fa84) mantled around a core of glass (K2O = 6.4, SiO2 = 78; both wt%).
Classification: Achondrite (Martian basaltic shergottite); moderate to high shock, minimal weathering.
Specimens: A 20.2 g type specimen and one thin section are on deposit at NAU. An anonymous owner holds the main mass.


Northwest Africa 2986

Algeria
Found 2006
Achondrite (Martian, basaltic shergottite)

History and physical characteristics: Three partially crusted stones of a total weight of 201 g were purchased in Erfoud, Morocco in 2006.
Petrography (T. Bunch and J. Wittke, NAU): A basaltic shergottite that contains pigeonite and augite (54 vol%), maskelynite (plagioclase) (41 vol%) and minor ulvöspinel, ilmenite, merrillite, chlorapatite, pyrrhotite, and K, - Si - rich, late stage glasses. Pyroxenes show mottled compositional zoning. Dark, shock pocket glasses and veins are also present.
Mineral compositions and geochemistry: Pigeonite Fs37.4-53.8Wo10.8-15.8 (FeO/MnO = 34); augite Fs27.8-40.6Wo33.4-36.0; maskelynite An54.7Or1.6. A few melt inclusions of K-, Si-rich glass, phosphates, ferroan pigeonite, and ilmenite, were found in ulvöspinel. Oxygen isotopes (D. Rumble, CIW): Replicate analyses of acid-washed whole rock samples by laser fluorination gave δ18O = 4.65, 4.59 ± 0.03, δ17O = 2.73, 2.67 ± 0.02, Δ17O = 0.28, 0.26 (all ‰).
Classification: Martian (basaltic shergottite) probably paired with NWA 2975. Low weathering grade and a moderate shock level.
Type specimen: 21.3 g are on deposit at NAU. M. Farmer and J. Strope are the main mass holders.

NWA 2986. Plane-polarized light. Image © T. E. Bunch, 2010.

NWA 2986. Partially crossed polarizers. Gray is maskelynite. Image © T. E. Bunch, 2010.


Northwest Africa 2990

Morocco
Found 2007
Achondrite (Martian, basaltic shergottite)

History and physical characteristics: This single, 363 g stone was recovered in Morocco (Western Sahara) in 2007 and purchased by Adam Aaronson in July 2008. The stone is 65% covered by very fresh, dark fusion crust; areas without fusion crust show a deeply etched surface from wind ablation. A few, thin shock veins are evident on the etched surface.
Petrography (T. Bunch and J. Wittke, NAU and A. Irving, UWS): A very fine-grained basaltic shergottite with small, zoned olivine phenocrysts (mean = 0.27 mm) that are set in a fine-grained groundmass (< 0.12 mm) of olivine, twinned tabular pigeonite, augite, maskelynite, chromite, titanomagnetite, ilmenite, FeS, and merrillite. The weathering grade is very low. The shock level is moderate and the shock level is moderate.
Mineral compositions: Olivine phenocrysts are typically zoned from cores of Fa37.6 to rims of Fa47.9 (mean FeO/MnO = 53), groundmass olivine is Fa45.8-49.7. Maskelynite is An64.3-66.2Or2.7. Pigeonite cores are Fs32.2Wo8.6, rims are Fs41.1Wo10.8 (FeO/MnO = 33). Augite is Fs26Wo28.8 (FeO/MnO = 29). Ilmenite contains 2.72 wt% MgO and chromite Cr/(Cr+Al) = 0.81-0.85.
Bulk Composition: Powder prepared from a ~1 gram representative interior piece was analyzed by XRF (M. Gellissen and H. Palme, U. Cologne) and INAA (R. Korotev, WUSL): wt.% SiO2 51.08, TiO2 0.62, Al2O3 9.24, FeO 16.42, MgO 8.06, CaO 11.67; ppm Sc 57.4, Cr 830, La 1.46, Sm 1.05, Eu 0.48, Yb 1.22, Lu 0.192. These data signify an enriched type of olivine-phyric shergottite, somewhat like NWA 1068.
Classification: Achondrite (Martian basaltic shergottite).
Type sample: A total of 21.1 g is on deposit at NAU. The main mass holder is Mr. Adam Aaronson.

NWA 2990. © T. E. Bunch, 2009.


Northwest Africa 5718

Northwest Africa
Found 2006
Achondrite (Martian, basaltic shergottite)

History and physical characteristics: A fresh, 90.5 g stone was purchased in Erfoud, Morocco by Mr. Darryl Pitt in 2009. The stone is complete and covered with a shiny, lightly weathered, melt flow fusion crust.
Petrography (T. Bunch and J. Wittke, NAU; A. Irving, UWS): This basaltic shergottite is fine to medium-grained (a few prismatic pigeonite grains reach 4.9 mm in length) with ophitic, subophitic, and granular textures. Pigeonite and augite account for 70 vol%, maskelynite (25 vol%), and ulvöspinel, ilmenite, pyrrhotite, and merrillite 5 vol%. Pigeonite and augite are compositionally zoned with mottled extinction, shock lamellae, and kink bands. Small pockets of late-stage K-rich glasses with crystallites of ilmenite, merrillite, pyroxene, and silica are also present. Shock-formed dark, vesicular glass pockets and thin shock melt veins are prominent.
Mineral compositions: Pigeonite cores, Fs0.5-39.1Wo9.6, rims, Fs41.8-45.7Wo12 (FeO/MnO = 32); augite Fs25.4-33.4Wo28.3-31.1, TiO2 = 1.49 wt% (FeO/MnO = 28). Plagioclase (maskelynite) is zoned with cores of An56.8Or2.1 to rims of An52.3Or4.8. Ilmenite MgO = 1.64 wt%. K-rich glasses (wt%) SiO2 = 77.1, Al2O3 = 11.6, K20 = 7.1, Na2O = 2.52, FeO = 1.45.
Geochemistry: Oxygen isotopes (D. Rumble, CIW): Replicate analyses of acid-washed whole rock samples by laser fluorination gave δ18O = 4.47, 4.29; δ17O = 2.60, 2.50; Δ17O = 0.253, 0.245 (all ‰). Bulk rare earth element abundances (ICPMS; C. Herd, U. Alberta): La 3.49, Ce 8.57, Nd 5.92, Sm 2.27, Eu 0.83, Gd 3.63, Dy 4.35, Er 2.53, Yb 2.23, Lu 0.32 (all in ppm).
Classification: Martian (basaltic shergottite). This specimen is an “enriched” shergottite with REE abundances ~ 10 x chondrites.
Type specimen: 20.1 grams are on deposit at NAU. Mr. D Pitt is the main mass holder.

NWA 5718. Fusion crust. © D. Pitt, 2009.

NWA 5718. Interior. © D. Pitt, 2009.

NWA 5718. Partially crossed polarized light image; 7 mm wide. Gray areas are maskelynite. © T. E. Bunch, 2009.