Watson 009        30°30’S, 131°41’E

South Australia, Australia

Found: 10 May 2009

Classification: Ordinary chondrite (H5)

History: K L. Bell found one piece, on the Nullarbor Plain.

Physical characteristics: Small (1.4 x 1.1 x 0.5 cm) dark brown, rusty specimen weighs 1.0 g. There is no obvious fusion crust or chondrules evident on the exterior. Small chondrules are best observed on a freshly cut surface.

Petrography: (Kim Lai N. Bell, Monash). Readily delineated chondrules lie within a heavily stained matrix, which makes it difficult to ascertain weather or not the matrix has been recrystallized. Chondrules range in size from 0.1-1 mm, with an average diameter of 0.5 mm and types include PO, POP, RP, BO and GOP. Mineralogy is typically chondritic and includes olivine, pyroxene, Fe-Ni metal and sulfides. Both olivine and pyroxenes have straight to undulose extinctions plus irregular fracturing. Metals (~11%), taenite and kamacite, as well as troilite (4%), occur as irregularly shaped grains that have been heavily replaced by oxides (96%).

Geochemistry: EMPA (wt%) Olivine: SiO₂ = 39.17, TiO₂ = 0.01, Al₂O₃ = 0.01, FeO = 17.26, MnO = 0.49, MgO = 43.29, CaO = 0.01, Na₂O = 0.01, K₂O = 0.00, (Fa = 18.28 mol%, σ = 0.09, n = 6). Low-Ca pyroxene: SiO₂ = 56.15, TiO₂ = 0.13, Al₂O₃ = 0.33, FeO = 10.96, MnO = 0.52, MgO = 31.01, CaO = 0.69, Na₂O = 0.02, K₂O = 0.01, (Fs = 16.27 mol%, σ = 0.19, n= 7). Kamacite: Ni = 6.88, Co = 0.33. Troilite: Ni = 0.00-0.82.

Classification: Ordinary chondrite (H5, S2, W4).

Specimens: Sample and one thin section held by A. Tomkins at Monash.