Brachnites
Name
*click on the Name for more information
Structure Class
achondrites
Chemical Class
Brachinites
Country
Year found
2007
Mass
1214 g
[Museum Collection]
(1) 5.136g
History: Two pieces purchased in July and a third one in September 2007 in Erfoud, Morocco. Physical characteristics: One complete stone broken into three pieces that fit together (weathered fracture), for a total weight of 1214 g (263+371+580). Partly covered with a slightly weathered, dark-brown fusion crust. Petrography: A. Jambon, O. Boudouma and D. Badia; (UPVI) Mineral mode (from BSE imaging) Olivine 88% orthopyroxene 6.5%, augite 1%, chromite 2.3% and plagioclase 1.7%. Accessories include weathered kamacite and Ni rich metal. Typical polygonal granular texture; grain size 0.2-0.4 mm. Geochemistry: Olivine Fa33±1, FeO/MnO = 66 (n=24). Orthopyroxene En70Fs27Wo2 FeO/MnO = 41, augite En46Fs11Wo44 FeO/MnO = 28, chromite Cr/(Cr+Al) = 0.79, Mg/(Mg+Fe)=0.22 and TiO2 = 1.05 wt%. Plagioclase An30. Oxygen isotopic composition (J. Gattacceca, C. Sonzogni, CEREGE) from analysis of two acid-washed 1.5 mg aliquots of a powdered 70 mg bulk sample is δ17O=2.49‰, δ18O=5.33‰, Δ17O=-0.30‰ (linearized, slope 0.5247, analytical uncertainties 0.08‰, 0.12‰, 0.03‰ respectively). Classification: Achondrite (Brachinite) Specimens: A total of 20.2 g of sample and one polished section is on deposit at UPVI. Moroccan Import Asnières, France holds the main mass.
Name
*click on the Name for more information
Structure Class
achondrites
Chemical Class
Brachinites
Country
Year found
2009
Mass
600 g
[Museum Collection]
(1) 8.17g
History: The meteorite was bought from a local meteorite dealer in Erfoud, Morocco. Physical characteristics: Dark-brownish rock without fusion crust. Petrography: A sawn surface of the meteorite shows up to 1 mm sized shiny crystals. It displays an equilibrium texture of equally sized olivine (about 80 vol.%) and orthopyroxene with abundant triple junctions between adjoining crystals. Along the grain boundaries symplectic exsolutions of orthopyroxene and Fe-sulfides are frequently observed. Minor phases are chromite and some phosphates. Geochemistry: olivine: Fa28.5±0.4 (Fa27.8-29.2, n=20, FeO/MnO=63±4); low-Ca pyroxene: Fs25.4±0.1Wo2.2±0.1 (Fs25.1-25.6Wo2.0-2.3, n=20, FeO/MnO=44±3) Classification: Mineral chemistry, high abundance of olivine, equilibrium texture and grain size are consistent with classification as brachinite.