Study Butte meteorite, Study Butte, Brewster County, Texas, USAi

Regional Level Types
Study Butte meteorite	Meteorite Fall Location
Study Butte	Table/Butte
Brewster County	County
Texas	State
USA	Country

Ordinary chondrite, unequilibrated (H3-6,br; S; W)
Found,1983; 417 g

A single meteoritic stone with its weathered (brown) fusion crust almost entirely intact was found just north of Big Bend National Park — roughly 2.2 km SSE of Study Butte. The meteorite is volumetrically dominated by its silicates (>75%, mostly olivine and 'bronzite') whose compositions — along with the meteorite's bulk iron content (26.9 wt%) — indicate its membership in the H-group (relatively high in total iron) of ordinary chondrites. Distinct chondrules are accompanied by light and dark chondrule fragments within a finegrained matrix of mostly H-chondritic composition.The dominant olivine and Ca-poor orthopyroxene are quite variable (Fa0.1-26, Fs1-16, respectively). Minor silicates include diopsidic pyroxene, plagioclase, and various glassy fragments. While Fe-Ni metal has often been oxidized, kamacite and lesser amounts of taenite and tetrataenite are present in significant quantities and are frequently associated with troilite. Various inclusions are also present including an achondritic fragment. However, the most striking features of the Study Butte meteorite are its carbide-magnetite aggregates which contain graphite and lesser amounts of cohenite and haxonite. Indeed, Study Butte appears to be one of the most graphite-rich members of the ordinary chondrites — if not, relatively speaking, the most graphite-rich.

The H-group ordinary chondrites represent the second largest group of witnessed meteorites falls and the largest group of ordinary of chondrite finds (meteorites recovered after their unrecorded arrivals). Study Butte belongs to the 58 member 'H3-6' subset of H chondrites (mixtures of unequilibrated and highly equilibrated H-chondritic material). As of early March 2017 only 2 witnessed H3-6 falls were known, Zag — the most massive (175 kg) — and Hainaut.

The main mass has been kept at the United States National Museum in Washington [a 261.12 specimen plus several very small specimens and thin sections as of March 2017].

Other Regions, Features and Areas containing this locality

References