Zmenj meteorite, Stolin District, Brest Region (Brest Oblast; Brest Voblast), Belarus

Latitude & Longitude (WGS84):	51° 49' 59'' North , 26° 49' 59'' East
Latitude & Longitude (decimal):	51.8333333333, 26.8333333333
Non-native locality type:	Meteorite
Other regions containing this locality:	Soviet Union

Howardite
Fell Aug 1858; 246 g

The Zmenj is a small Howardite and, like all Howardites, is a brecciated mixture of Eucritic pyroxene-plagioclase intergrowths with Diogenitic orthopyroxenes. However, Zmenj has been perhaps a little more obviously battered by the process as this small porous stone is rich in small clasts, melt particles, quenched melt, dendritic troilite, and partially devitrified features. Orthopyroxene (hypersthene composition) is the primary pyroxene, but pigeonite and clinopyroxene lamellae are also reported. Plagioclase is mostly anorthitic, but is still quite variable. Several minor silicates and opaques commonly found in Eucrites, Howardites, and/or Diogenites are found. Olivine, silica, chromite, ilmenite, troilite are referenced here as well as small amounts of Ni-poor iron and moderately complicated Fe-Ni particles.

Howardites belong to a clan of clearly related group of achondritic meteorites — the Howardites, Eucrites, and Diogenites (or, 'HED meteorites'). Zmenj appears at this level of detail to be a typical Howardite — indeed, except for a small chondritic component (~2%), it is a roughly half-half mixture of Eucritic and Diogenitic components. In all likelihood, as an HED meteorite, Zmenj is a fragment of material which was first mixed together on the asteroid 4 Vesta and then ejected into space. Then, over a century ago, chance and subsequent collisions, further fragmentation, and gravitational perturbations had eventually combined to collide with the planet earth as the 4th of only 16 observed Howardite falls (as of Sept 2014).

Zmenj is a likely fragment of Vesta, but not necessarily a definite fragment. A few odd rocks — 'anomalous HEDs' — display unusual O-isotope and Fe/Mn ratios which bespeak a plural number of HED parent bodies. And, a few odd asteroids with basaltic or igneous surfaces might easily be among the parent bodies of a few HED meteorites. More work needs to be done, apparently, before we can be as definite about specific HED meteorites as we are now about lunar and Martian meteorites.

Mineral List

8 valid minerals.

References

External Links