Thumb Butte 35º 10.196´N 114° 27.351´ W
Mojave County, Arizona, USA
Find: 1 March 2008
Ordinary chondrite (H3.8)
History: Mr. Todd Parker found a 104 g stone on a small, alluvium-covered flat just west of Thumb Butte and 4 miles east of Bullhead City, Mojave Co., Arizona.
Physical characteristics: The single stone is mostly covered by moderately weathered reddish-brown fusion crust.
Petrography (T. Bunch and J. Wittke, NAU): Chondrules have sharp outlines with a mean diameter of ~0.4 mm. Matrix is slightly recrystallzed with some remnant calcic glass. Chondrule mesostasis is clear to turbid and several chondrules are armored with metal and minor FeS. Contains olivine, orthopyroxene, kamacite, FeS, taenite, merrillite, Cl-apatite, chromite and a trace of plagioclase. Fresh interior with reddish staining, weathering grade is W1. Shock level is S2.
Mineral compositions: Olivine, Fa17.3 – 24; orthopyroxene, Fs15.7 – 19.1Wo 1.5 – 2.3; taenite Ni = 41.2 wt%; chromite cr# = 86.
Classification: Ordinary chondrite (H3.8).
Type specimen: 20 g are on deposit at NAU. Mr. Todd Parker holds the main mass.