Northwest Africa 12772 (NWA 12772)

(Northwest Africa)

Purchased: 2015 Sep

Classification: Carbonaceous chondrite (CV3)

History: Purchased by Michael Farmer from a meteorite dealer at the Denver Gem and Mineral Show, September 2015.

Physical characteristics: Whole stone mostly covered with black fusion crust.

Petrography: Dominated by abundant large (0.1 to 4 mm, mean 0.8 mm; N=165 chondrules; 54.8 vol.%) FeO-poor and FeO-rich chondrules (FeO-poor chondrules are dominant) with unequilibrated silicates (Fa_0.4-43.5) set in an FeO-rich fine-grained matrix (40.9 vol.%). Chondrule types include C, POP, PO, and BO. The meteorite contains abundant CAIs (4.3 vol.%), and contains a large type B CAI (3.5±1.6 mm in apparent dimensions). Similar to the reduced CV3 chondrite RBT 04133 (Davidson et al., 2014), Ni is not positively correlated with Co (e.g., Ni-poor Fe,Ni metal with 4.84 wt.% Ni and 1.93 wt.% Co, and Ni-rich Fe,Ni metal with 46.49 wt.% Ni and 0.65 wt.% Co).

Geochemistry: Olivine: overall Fa_11.4±15.5, Fa_0.4-43.5; N=25; FeO-poor chondrules (Fa_0.7±0.3, Fa_0.4-1.1; N=15); FeO-rich chondrules (Fa_27.4±12.8, Fa_3.2-43.5; N=10).

Classification: Carbonaceous chondrite (CV3)

Specimens: 198.75 g at ASU.