Southwest Medium Octahedrite
Item: 65.1 Dimensions: 52 x 42 x 11 mm Weight: 164.1 g
Provenance: United States National Museum, Smithsonian
Partial/complete: Partial slice
Cube: ~15mm x 15mm x 15mm ≈ 15mm3

Four Corners

Country: USA
Region: New Mexico
Found: 1924
Group: Iron
Type: Octahedrite, Medium
Class: IAB-ung
Total known weight: ~25kg

A mass of about 25kg was found 15 miles SE from the common corner of Colorado, New Mexico, Arizona and Utah, M.H.Hey, Cat. Met., 1966, p.165. Description and analysis of iron and silicates, 9.57% Ni, G.P.Merrill, Proc. Nat. Acad. Sci., 1924, 10, p.312. Mentioned, B.Mason, Min. Mag., 1967, 36, p.120. Rb-Sr dating of silicate inclusions, D.S.Burnett and G.J.Wasserburg, Earth Planet. Sci. Lett., 1967, 2, p.397. Analysis of metal, 8.90% Ni, 48.7 ppm Ga, 179 ppm Ge, 2.0 ppm Ir, J.T.Wasson, Icarus, 1970, 12, p.407. Silicate inclusions of the Copiapo type, T.E.Bunch et al., Contr. Mineral. Petrol., 1970, 25, p.297. Orthopyroxene Fs6.5 in silicate inclusions, J.T.Wasson, GCA, 1970, 34, p.957. K-Ar age of inclusions, about 4.5 Ga, D.D.Bogard et al., Earth Planet. Sci. Lett., 1968, 3, p.275. Xe and Kr isotopic composition of silicates, D.D.Bogard et al., GCA, 1971, 35, p.1231. Metallographic description, polycrystalline parent taenite has decomposed to kamacite plus taenite, V.F.Buchwald, Handbook of Iron Meteorites, Univ. of California, 1975, p.573. Si isotopic composition of silicate, C.Molini-Velsko et al., GCA, 1986, 50, p.2719. Ni, Cu and Se abundances in troilite, S.R.Sutton et al., GCA, 1987, 51, p.2653. Nitrogen isotopic composition, I.A.Franchi et al., GCA, 1993, 57, p.3105. Ni concentration profiles in taenite lamellae, cooling rates, M.A.Herpfer et al., GCA, 1994, 58, p.1353. New analysis, B.G.Choi et al., GCA, 1995, 59, p.593. Oxygen isotopic composition, R.N.Clayton and T.K.Mayeda, GCA, 1996, 60, p.1999; see also, R.N.Clayton et al., LPSC, 1983, 14, p.124 (abs.). Nitrogen content and isotopic composition, K.V.Ponganis and K.Marti, MAPS, 1998, 33, p.A125 (abs.). Petrology of silicate inclusions, G.K.Benedix et al., MAPS, 2000, 35, p.1127. New classification: an ungrouped member of the IAB complex, J.T.Wasson and G.W.Kallemeyn, GCA, 2002, 66, p.2445.