Shawnee

Kansas, Johnson County, United States

Purchased: 2010

Classification: Iron meteorite (IAB-MG)

History: A single 8181 g mass was acquired at an estate sale in Shawnee, Kansas. The meteorite had been used for many years as a doorstop by a couple that lived in Shawnee. The owners of the meteorite originally owned farm ground in Barton County, Kansas, but lived for the better part of their lives in Shawnee. Unfortunately, the exact find location is unknown. A small end piece was sent to ASU and confirmed to be a meteorite.

Physical characteristics: Surface shows some fusion crust and minor weathering with broad regmaglypts.

Petrography: (L. Garvie, ASU) Etched sections show a coarse Widmanstätten structure, with stubby kamacite, bandwidth 1.3 mm. Kamacite lamellae display subboundaries and numerous μm-sized phosphide precipitates. Sub-millimeter schreibersite common within some kamacite grains and at grain boundaries. Neumann bands straight and well developed in rhabdite-free grains. Thin taenite and plessite cover several percent by area. Inclusions common - one 7 × 5 cm slice exhibits several (to 2 cm) irregular silicate-graphite-troilite-schreibersite regions. Silicates consist of olivine, low-Ca pyroxene, clinopyroxene, and plagioclase. Slice contains several 1-mm blocky schreibersite with cohenite rims.

Geochemistry: Bulk composition: INAA data (Activation Laboratories - Ancaster, Ontario): Co 0.46 mg/g, Ni 74 mg/g, Ga 57 μg/g, Ge 180 μg/g, Ir 2.24 μg/g, and Au 1.50 μg/g.

Classification: Iron meteorite, IAB-MG, coarse octahedrite, moderately shocked.

Specimens: Type specimens - two slices with total weight of 144.6 g.