Iron, IAB complex, Udei Station grouplet
Found ~1923
36° 51' N., 108° 51' W.
A mass of 25 kg was found 24 km SE of the common corner of New Mexico, Arizona, Colorado, and Utah, but the find location is given as New Mexico. The meteorite was acquired by a geologist in 1923, but he failed to report any further details before his death in that year.
The metal in Four Corners has a small-grained, polycrystalline structure, exhibiting independently oriented Thomson (Widmanstätten) structures. Chondritic, angular, silicate inclusions composed of grains of enstatite, diopside, olivine, and plagioclase up to 20 mm wide make up 15% of the meteorite by area. Graphite is present throughout and occurs as crystals of cliftonite in troilite and kamacite, as rims around silicate grains, and as graphite patches containing amorphous carbon. The K–Ar closure age for Four Corners was calculated to be 4.50 (±0.01) b.y.
Four Corners is a medium octahedrite of the IAB iron-meteorite complex (Wasson and Kallemeyn (2002). To learn more about the relationships within the IAB complex and among other iron chemical groups, click here. The specimen pictured is an etched 10.3 g partial slice.
