Northwest Africa 2046

Olivine Orthopyroxene Phyric Shergottite

planetmars.JPG (26244 bytes)


  • Northwest Africa 2046 (NWA 2046)
  • Found in Algeria or Morocco
  • Purchased September 2003
  • Martian basalt - Olivine Orthopyroxene Phyric Shergottite

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.

30th MARTIAN METEORITE FOUND IN ALGERIA: NWA 2046:  from the Jet Propulsion Laboratory, California Institute of Technology website.

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 (pdf file).

Classification details from NAU


Click Images to enlarge:       All photos and text are copyright and may not be used without permission.


nwa2046whole.JPG (144246 bytes)

Whole stone before cutting.

nwa2046b.JPG (180631 bytes)

Cut face.

 thinsection1.jpg (266238 bytes)

Shows olivine phenocrysts set in pyroxene and maskelynite. - Base = 23 mm

thinsection2.jpg (469116 bytes)

Shows plane lite, partial polarized and fully polarized light. - Base = 4 mm

thinsection3.jpg (336374 bytes)

Shows megacryst or phenocryst. - Base + 3mm

thinsection4.JPG (308478 bytes)

  thinsection5.JPG (317596 bytes)   False-color BSE images

mmemail.gif (1175 bytes)

Home | Sikhote-alin Meteorites | All Other Meteorites | Photo Gallery

Ordering Information | Found a Meteorite?