Astoria        44°33.238’N, 96°31.169’ W

South Dakota, United States

Find: 1961

Classification: Iron meteorite (IIIAB)

History: (C. Alexander, UMin; M. Hutson, Cascadia): The meteorite was found by a teenager who was plowing the family farm near Astoria, SD, in 1961. Based on that individual’s memory, the meteorite was found about 3.5 km ESE of Astoria, in Minnehaha County. He suspected it was a meteorite and stored it in a machine shed on the farm. The teenager grew up, married, ran the family farm and raised his family there. When he retired in the early in the 21st century, he and his wife left the farm, moved to Sioux Falls, SD, and took the meteorite with them. When his wife read some of the publicity associated the recognition of the High Island Creek iron meteorite and realized it might be valuable, they contacted Calvin Alexander at the University of Minnesota in 2015 and sent photos of the meteorite. Based on a positive response to the photos, the couple brought the object to Minneapolis. A quick pXRF analysis indicated that it was indeed an iron meteorite. The meteorite was purchased by Marlin Cilz and Calvin Alexander. Cilz received 80% of the meteorite and sold the 21.45 kg main mass to the Utas Collection. Two slices totaling 200 g were taken from the 20% of the meteorite retained by Alexander, and were sent to John Wasson for chemical analysis and for the UCLA collection. An additional 235.3 g slice was sent by Alexander to Cascadia for a type specimen.

Physical characteristics: Physical Characteristics: (C. Alexander, UMin; M. Hutson and A. Ruzicka, Cascadia): Prior to cutting, the sample was a single meteorite about 33 × 25 cm, with a dark brown regmaglypted exterior.

Petrography: (A. Ruzicka, Cascadia): Structure is Om, typical of a IIIAB iron, with a kamacite bandwidth of 1.0±0.24 mm, N=27. Sparse schreibersite laths up to 1 cm in length, as well as one large (approximately 1.5 cm wide) troilite nodule are present.

Geochemistry: (J. Wasson, UCLA): Composition: Cr 91 µg/g; Co 4.95 mg/g; Ni 72.7 mg/g; Cu 187 µg/g; Ga 18.3 µg/g; As 3.34 µg/g; W 1.27 ng/g; Ir 15.9 µg/g; Pt 14.7 µg/g; Au 0.494 µg/g.

Classification: Iron, IIIAB based on composition and structure.

Specimens: 21.45 kg JUtas (main mass), 235.3 g Cascadia, 198.8 g (UCLA), 3740.7 g (CAlexander).