Northwest Africa 5789 Martian Meteorite

Original fragment of NWA 5789.
Original fragment of NWA 5789.


Official Meteoritical Bulletin entry for Northwest Africa 5789:

Northwest Africa 5789
     Morocco
     Find (found January 2009, purchased May 2009)
     Achnodrite (Martian, olivine-phyric shergottite)

History: A small chip from one of three crusted stones found together in Morocco was sent from a dealer in Erfoud to Greg Hupé, and subjected to preliminary testing at UWS. Subsequently the stones were purchased in May 2009 by Stefan Ralew and Martin Altmann. [Moroccan dealer had no intentions of selling to Hupé, just used for confirmation].
Physical characteristics: A 49 g partly crusted stone, naturally broken into three pieces that fit together (Fig. 4a). The interior consists mainly of pale yellowgreen olivine macrocrysts in a light brownish-gray, finer-grained matrix (Fig. 4b). No maskelynite is evident. Several exterior sides are coated by glossy black fusion crust, which contains embedded rounded quartz grains.
Petrography: (A. Irving and S. Kuehner, UWS; J. Gross, A. Treiman, K. Robinson, LPI) Small (up to 1 mm), zoned olivine macrocrysts (in multi-crystalline clusters) with narrow ferroan rims are set in a finer grained groundmass composed mainly of prismatic low-Ca pyroxene grains with accessory olivine, chromite, pyrrhotite, and small regions of mesostasis (approximately 2 vol%) composed of subparallel, laminar to sheaf-like intergrowths of pigeonite, intermediate plagioclase, silica, ilmenite, and merrillite. The pyroxenes exhibit chaotic compositional zoning, with low-Ca pyroxene cores, regions of pigeonite and augite, and narrow ferropigeonite rims.
Geochemistry: Olivine macrocrysts (cores Fa15.616.6, FeO/MnO = 45.249.4; mantle Fa22.6, FeO/MnO = 47.6; rim Fa45.4, FeO/MnO = 58.9), matrix olivine (Fa47.3, FeO/Mno = 61.1), low-Ca pyroxene (cores as magnesian as Fs17.1Wo1.6, FeO/MnO = 30.9), pigeonite
Classification: Achondrite (Martian, olivine-phyric shergottite). This specimen has mineralogical and bulk compositional similarities to Yamato 980459/980497, but differs from those stones in having very little mesostasis.
Specimens: A total of 9.8 g, two polished thin sections and a polished mount are on deposit at UWS; a further 5.6 g of material is held by A. Treiman (LPI) and another 3.3 g at UAb. The remaining material is held by anonymous collectors and institutions.

Scientific abstracts and news regarding NWA 5789:

Irving A.J., Kuehner S.M., Tanaka R., Herd C.D.K., Chen G. and Lapan T.J.
(2012b) The Tissint depleted permafic olivine-phyric Shergottite:
Petrologic, elemental and isotopic characterization of a recent Martian Fall in Morocco (abs#2510).
Lunar Planet. Sci. XLIII,
Lunar Planetary Institute @ The Woodlands.
http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2510.pdf

Matzen A.K., Beckett J.R., Baker M.B. and Stopler E.M.
(2011) Fe2+-Mg partioning between olivine and Martian basaltic melts (abs#5528).
Meteorit. & Planet. Sci. 46, A150.
http://www.lpi.usra.edu/meetings/metsoc2011/pdf/5528.pdf

Franz H.B., Farquhar J. and Irving A.J.
(2010) Acid volatile sulfur isotopic composition of seven Shergottites from Northwest Africa (abs#2341).
Lunar Planet. Sci. XLI.
Lunar Planetary Institute Houston.
http://www.lpi.usra.edu/meetings/lpsc2010/pdf/2341.pdf

Gross Juliane, Treiman A.H., Filiberto J. and Herd C.D.K.
(2010) Primitive olivine-phyric Shergottite NWA 5789: Petrology, mineral chemistry and cooling
history imply a magma similar to Yamato-980459 (abs#1813).
Lunar Planet. Sci. XLI, 287-288.
Lunar Planetary Institute, Houston.
http://www.lpi.usra.edu/meetings/lpsc2010/pdf/1813.pdf

V.H. Hoffmann1,2, M. Funaki3, M. Torii.
(2010). COMPARING THE MAGNETIC SIGNATURE OF NWA 5789 AND YAMATO
980459 OLIVINE PHYRIC SHERGOTTITES. (abs#5338).
http://www.lpi.usra.edu/meetings/metsoc2010/pdf/5338.pdf

Irving A.J., Kuehner S.M., Herd C.D.K., Gellissen M., Korotev R.L., Putchel I., Walker R.J., Lapan T.J. and Rumble D.
(2010b) Petrologic, elemental and multi-isotopic characterization of permafic olivine-phyric Shergottite
Northwest Africa 5789: A primitive magma derived from depleted Martian mantle (abs#1547).
Lunar Planet. Sci. XLI,
Lunar Planetary Institute @ The Woodlands.
http://www.lpi.usra.edu/meetings/lpsc2010/pdf/1547.pdf

Weisberg M.K. et al.
(2010a) Met. Bull #97. Meteorit. & Planet. Sci. 45, 449-493.


One of three fragments from NWA 5789 - View 1.
One of three fragments from NWA 5789 - View 1.
  One of three fragments from NWA 5789 - View 2.
One of three fragments from NWA 5789 - View 2.

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