Yurtuk Meteorite, Vasylivka Raion, Zaporizhia Oblast, Ukrainei

Regional Level Types
Yurtuk Meteorite	Meteorite Fall Location
Vasylivka Raion	Raion
Zaporizhia Oblast	Oblast
Ukraine	Country

Howardite
Fell 2 Apr 1936; 1.472 kg

A 509 g stone fell through the roof of a house while other fragments were recovered outside. Yurtuk was only the 11th of 16 witnessed Howardite falls during the 19th and 20th centuries. Howardites are primarily brecciated mixtures of Eucritic basaltic materials and Diogenitic orthopyroxenite. The Eucritic and Diogenitic material in Yurtuk has been partially equilibrated and ancient, shock-produced glass partially devitrified. However, the variable overall composition of silicates grains and, especially, the iron-enhanced rims of small silicate minerals indicate that the equilibrating process was left unfinished when the Yurtuk material was launched into space (presumably after an unusually strong impact event). In addition to the predominant orthopyroxene, pigeonite and anorthitic plagioclase commonly found in almost all Howardites, a number of minor phases have been reported. Minor silicates include variable olivine and silica (tridymite and perhaps others). Opaques include chalcopyrite, chromite, ilmenite, and three varieties of Fe-rich metal (kamacite and taenite ['meteoritic iron' properly speaking], plus some unusual Ni-poor iron).

Howardites are members of the HED clan of achondritic meteorites (Howardites-Eucrites-Diogenites) that were formed by a combination of igneous differentiation and impact gardening on moderately large asteroidal parent bodies. Four decades of astronomical and meteoritical study — including the recently completed DAWN mission — have made it clear that most HED meteorites are fragments of asteroid 4 Vesta. Recent studies using very high precision studies of oxygen isotope ratios have also made it almost certain that a not-insignificant fraction of HED meteorites (especially Eucrites) must have had separate parent bodies. Nothing in the mineralogical record cited here is inconsistent with Vesta being the Original Parent Body (OPB) for Yurtuk, but more work will be done to establish precisely which HED meteorites are indeed Vesta fragments and which are petrological 'look-alikes.' After all, the important Martian meteorite, ALH84001, was originally classified as a 'Diogenite.'

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