F3/4 (forsterite) chondrite (S2/W2)
Mineralogy and Oxygen Isotopic Composition of Exotic F6 Chondrite Clasts in the Cumberland Falls Aubrite
S. M. Kuehner, J. H. Wittke, K. Ziegler, A. J. Irving
47th Lunar and Planetary Science Conference (2016), Abstract #2304
F3/4 Chondrite Northwest Africa 7135: Further Assessment of Its Relationship to Clasts in the Cumberland Falls Aubrite
Kuehner S. M., Irving A. J., Ziegler K., Sanborn M. E., Yin Q.
78th Annual Meeting of the Meteoritical Society (2015), abstract #5238
NWA 7135
by David Weir
Northwest Africa 7135: An Unusual Reduced, Unequilibrated Chondrite Containing Oldhamite, Daubreelite, Schreibersite and Djerfisherite, and with a Unique Oxygen Isotopic Composition
A. J. Irving, S. M. Kuehner, K. Ziegler, F. Kuntz, P. P. Sipiera
46th Lunar and Planetary Science Conference (2015), Abstract #2437
NWA 7135 – 0.64 g part slice
NWA 7135 cut main mass / photo: F. Kuntz
NWA 7135 main mass / photo: F. Kuntz
NWA 7135/F chondrite oxygen isotope plot from: Kuehner S. M., Irving A. J., Ziegler K., Sanborn M. E., Yin Q. / 78th Annual Meeting of the Meteoritical Society (2015), abstract #5238
Meteoritical Bulletin Database (22 January 2015)*
Northwest Africa
Purchased: 2010 Oct
Classification: Ungrouped chondrite
History: Purchased by Fabien Kuntz in October 2010 from a Moroccan dealer at the Munich Show.
Physical characteristics: Brown stone (51.3 g) lacking fusion crust and with evident light-colored, round chondrules.
Petrography: (A. Irving and S. Kuehner, UWS) Composed of separated, mostly spherical, relatively small chondrules (mean 0.69±0.53 mm, n=40) in a matrix (~30 vol.%) rich in altered kamacite. Some chondrules contain interstitial feldspathic glass. Minerals are olivine, zoned orthopyroxene, pigeonite, diopside, subcalcic augite, Cr-rich chromite, pyrrhotite, pentlandite, daubreelite, oldhamite, schreibersite and rare barite. The presence of highly reduced sulfides and phosphides suggest an atypical ordinary chondrite.
Geochemistry: Olivine, predominantly Fa4.8-6.3 (N = 15), with some more ferroan grains Fa19.8-19.9 (N = 2); orthopyroxene, Fs7.0-21.8Wo0.4-1.5 (N = 3); pigeonite, Fs17.3Wo6.9; subcalcic augite, Fs13.3-22.2Wo25.4-29.9 (N = 2). The mean olivine composition (Fa6) is much more magnesian than for H chondrites of similar subtype. Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively, δ17O = 3.207, 3.649, 3.262, 3.379, 3.859; δ18O = 5.175, 6.072, 5.326, 5.333, 6.450; Δ17O = 0.475, 0.443, 0.450, 0.563, 0.453 (all per mil). Oxygen isotopes plot in a region above the TFL and at relatively high δ18O values.
Classification: Ungrouped chondrite, high metamorphic type 3 or type 4.
Specimens: 10.44 g including one polished thin section at PSF; main mass with Kuntz.
NWA 7135 oxygen isotope plot / Meteoritical Bulletin Database
