New class of carbonaceous chondrites ! CL 3.9 (currently C3 ungrouped but will be changed).
0.01g part slice
Sold in a collection box with label / certificate of authenticity
Northwest Africa 13400 (NWA 13400)
Purchased: 2016 Dec
Classification: Carbonaceous chondrite (C3, ungrouped)
Petrography: (K. Metzler, IfP) Carbonaceous chondrite, consisting of closely packed, metal-bearing chondrules (apparent size up to 2.8 mm), chondrule fragments, and CAIs (apparent size up to 3.8 mm) with low amounts of interchondrule matrix (17 vol%). The mean apparent chondrule size is 480 µm (n=512).
Geochemistry: Mineral compositions and geochemistry: The mean olivine composition is Fa14.7±1.3 (Fa10.2-16.0, n=30); the mean low-Ca pyroxene composition is Fs6.6±3.7Wo1.0±0.1 (Fs1.2-15.9Wo0.8-1.2, n=20). Oxygen isotopic composition (R. Greenwood, OU): δ17O=-4.017‰, δ18O=-0.021‰, Δ17O=-4.006‰.
Classification: Carbonaceous chondrite (ungrouped). Petrologic type 3.9 based on the percentage mean deviation (PMD) of Fa values (8.8%). Classified as ungrouped due to the low mean Fa and Fs values of olivine and low amount of matrix compared to e.g., CV chondrites. Chondrule size does not fit with either CV, CK or CK chondrites that are the closest groups in terms of oxygen isotopic composition.