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Name: Northwest Africa 12455, NWA 12455
ACCN:
Type: Chondrite, CR7
Fall: Unknown
Found: 2018
Location: Desert of Northwest Africa
Coordinates: Unknown
TKW: 611 g
Chemical Composition:Olivine (Fa35.0-35.3, FeO/MnO = 83-94, N = 4), orthopyroxene (Fs27.8-28.0Wo3.5-4.0, FeO/MnO = 51-56, N = 4), plagioclase (An48.2-48.9Or1.1, N = 2), kamacite (Ni = 7.2 wt.%), taenite (Ni = 16.4 wt.%). Oxygen isotopes (K. Ziegler, UNM): analysis of acid-washed subsamples by laser fluorination gave, respectively: δ17O 0.661, 0.470, 0.296, 0.359, 0.375, 0.303; δ18O 4.314, 4.021, 3.637, 3.840, 3.939, 3.761; Δ17O -1.617, -1.653, -1.625, -1.668, -1.705, -1.683 per mil. Chromium isotopes (M. Sanborn and Q. Yin, UCD): 54Cr is the same within analytical uncertainty as that for CR2 chondrite Renazzo reported by Sanborn et al. (2019).
Age:
Additional Information:
External References: 1) Met. Bull. Database
2) Encyclopedia of Meteorites
Notes: Chondrules are compleately absent and texture is throughly rechristalized. Both the petrographic and oxygen isotope results establish this as very reare CR7 chondrite. Tafassasset (or NWA 5131) is regarde to be a CR7 chondrite, but this NWA 12455 is even more recrystallized and possibly should be regarded as the first CR8!
At the moment only 2 meteorites are clasified as CR7 with total mass on Earth only 1479 grams.
Exhibit
Item: Slice
[Image]
 
Inventory Code: M-NWA12455.1
Registration Year: 2019
Origin: Big Bang Meteorites, IMCA#2430
Size: 49 × 28 × 1 mm
Weight: 8.27 g
Short Description:
Related Items:
Notes:
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