Mocs meteorite, Mociu, Cluj County, Romaniai

Regional Level Types
Mocs meteorite	Meteorite Fall Location
Mociu	Commune
Cluj County	County
Romania	Country

Ordinary chondrite, veined (L5-6; S3-5; W0)
Fall, 3 February 1882; 300 kg, shower

After an intensely brilliant fireball was seen in a cloudless sky, a rolling noise and violent detonations were heard,and a shower of several thousand stones fell along a 14x 3 km tract near the village of Mocs. The most massive stone had a mass of 56 kg. Examination of the interior of Mocs under the microscope usually reveals a number of poorly defined mm-sized chondrules (BO, PO, PP, POP) dominated by olivine (Fa23) and orthopyroxene crystals accompanied by devitrified glass. (A few sections have clearly defined chondrules). Minor albitic plagioclase is present along with very rare maskelynite. Irregular-shaped troilite and Fe-Ni metal aggregates tend to congregate near the relic chondrules. Planar fractures, glass, plessite, undulatory extinction, olivine mosaicism, and melt pockets are all seemingly indicative of strong, but varying levels of shock within the meteorite. In addition, cosmogenic radionuclides and CRE 'ages' suggest a complex history involving burial at some depth on a moderately large meteoroid for ~100 Ma followed by exposure inside an object ≤ 1m in diameter for ~10 Ma before its eventual earth impact.

Total iron (21.8 wt%) content as well as olivine (Fa23) and orthopyroxene (Fs21) composition indicate that Mocs is a member of the L (low iron) ordinary chondrite geochemical group. The petrological type, however, appears to be somewhat uncertain. Grady et al. (2015) classify Mocs as an 'L6', but Mocs is classified as L5-6 at the Meteoritical Bulletin Database. Only 2 witnessed falls — Mocs and Pleşcoi, another Romanian fall — are classified exactly as L5-6 chondrites at the Database. One suspects that the complex shock history may have added some additional wrinkles to the Mocs story.

Large masses have been held at the Naturhistorisches Museum in Wiens (70 kg), the National Museum of Transylvania History in Cluj, Romania (42.8 kg), and the Hungarian Natural History Museum in Budapest (21 kg) with a number of moderate masses elsewhere.

Nota bene: The name for the village of Mocs (once in Hungary) has been changed to Mociu as it is now a part of Romania.

Other Regions, Features and Areas containing this locality

References