NWA 11435 CK5

Northwest Africa 11435 (NWA 11435)

(Northwest Africa)

Purchased: 2017 May

Classification: Carbonaceous chondrite (CK5)

Petrography: (K. Metzler, IfP) Chondrules with apparent diameters up to 1.3 mm and CAIs are embedded in a fine-grained brownish matrix. Opaques are Cr-bearing magnetite and pentlandite. No metal was found .

Geochemistry: Mineral compositions and geochemistry: Olivine composition Fa_31.7±0.2 (31.5-32.2; n=15). Composition of low-Ca pyroxene Fs_26.2±0.5 (25.4-27.5); Wo_0.8±0.3 (0.5-1.6; n=15). Composition of Ca-rich pyroxene Fs_9.9; Wo_45.7 (n=2).The compositional range of feldspar (n=2) is An_38-40. One plagioclase grain in a CAI shows An_86. Most abundant opaques are Magnetite and Pentlandite. No metal was found. Magnetite shows significant concentrations of elements other than Fe (n=4): MgO 0.4 wt%; Al₂O₃ 1.9 wt%; Cr₂O₃ 5.4 wt%.

Classification: CK chondrite based on mineral chemistry. Petrologic type 5 based on the equilibrated state of olivine and pyroxene and clear visibility of chondrules.