Northwest Africa 480 (NWA 480)
NWA 480 Photo © Bruno Fectay & Carine Bidaut JPEG (132K) A Mars meteorite stone (shergottite) weighing 28 grams. The meteorite has been sliced open to show its interior.	NWA 480 Photo © Bruno Fectay & Carine Bidaut JPEG (123K) Closeup of the interior of the meteorite.

                    THE METEORITICAL BULLETIN
               Announcement 85-4, April 4, 2001
         Jeffrey N. Grossman, Editor (jgrossman@usgs.gov)
          Jutta Zipfel, Co-editor for Saharan Meteorites 
                  (zipfel@mpch-mainz.mpg.de)

Northwest Africa 480
  Northwest Africa
  Found 2000 November
  Martian meteorite (basaltic shergottite)
A 28 g stone almost completely covered with fusion crust was found in 
Morocco. Classification and mineralogy (J.-A. Barrat, UAng, A. 
Jambon, UPVI, Violaine Sautter, MNHNP, Ph. Gillet, ENSL): the 
meteorite has a coarse-grained basaltic texture consisting 
predominately of subhedral to euhedral pyroxene (up to 3 mm) and 
interstitial, lath-shaped maskelynite; accessory minerals include 
merrilite, chlorapatite, pyrrhotite, Fe-oxides, fayalite and silica; 
pyroxenes show complex zonation with Mg-rich pigeonite cores (Fs26 
Wo4), followed by augite (Fs29 Wo30), and mantled by Fe-rich 
pigeonite (Fs84 Wo11); no pyroxferroite has been detected; 
maskelynites homogeneous, An46-50 Ab52-48 Or~2; merrilite forms 
rounded grains (up to 100 um) and is Fe-rich (~5 wt. % FeO),  
commonly with 6-40 um thick rims of fayalite (Fa~95), silica, Fe-Ti 
oxides, and pyrrhotite; silica (stishovite) occurs as irregular 
grains in maskelynite or at grain boundaries to pyroxene and is 
surrounded by radiating cracks. Oxygen isotopes (M. Javoy and E. 
Petit, IPGP): d18O = +4.78 permil, d17O = +2.91 permil and D17O = 
+0.42. Specimens: main mass, 25 g, CNES. 

Return to the Mars Meteorite Home Page