The Naragh Meteorite: A New Olivine‐bronzite Chondrite Fall

Abstract

(EnU,FS82WOOl) are intergrown with olivine in both chondrules and matrix. Clinopyroxene and plagioclase of average composition (En6.sFs48W045.sJ and (Ab81!'1n120rorJ respectively, are evenly distributed in the matrix, Meteoritics, Vol. 14, No.3, September 30,1979 257 the presence of numerous recrystallized chondrules with homogeneous silicate minerals, and the absence of Ni in the sulfide phase indicate that the Naragh meteorite has been metamorphosed after the initial crystallization in the parental body. INTRODUCTIONAt about 9:20 AM. on August 18, 1974, the janitor of the Secondary School at Naragh, Central Iran (approximate coordinates 51°30'E, 33°45'N), was alerted by a crushing sound in the building. He then discovered on the second floor two very hot objects which were later identified as parts of a meteorite. The force of the impact broke the 3200 gram meteorite into two pieces and produced a hole of about 30 cm in diameter through the roof. The meteorite was suggested to have fallen from a northwesterly direction, striking the building at an angle of about 45°. At least 35% of the surface of the meteorite was covered with asphalt material from the roof, 25% was covered with a black fusion crust of 0.5 to 1 mm thickness,and the remaining fresh surface shows a dark greenish-gray color. The meteorite is ellipsoidal in shape, 17 X 15 X 13 cm in dimensions and its specific gravity was determined to be 3.62 grams/em". The meteorite is now displayed at the Geophysical Institute, Tehran University, Iran.The general properties of the Naragh meteorite have been briefly mentioned by Eshghi (1975); however, its petrochemical and mineralogical aspects have not been investigated. This report describes petrographic features, chemical compositions, the constituent minerals of the meteorite, and comments on its petrogenesis. METHOD OF STUDYSix polished thin sections from various portions of the Naragh meteorite were prepared for petrographic study and electron microprobe analysis. The sections were examined in detail with petrographic microscope to determine the textural relationships and primary and metamorphic minerals. The modal composition of the meteorite was determined by point counting, and the bulk chemistry was determined by XRF and classical chemical analyses; the results are shown in Table 1.Chemical compositions of minerals were analysed with ARL-EMX-SM and MAC electron microprobes at Stanford University and Charles Taylor's Company respectively. As will be described in the later section, the meteorite is texturally heterogeneous. In order to analyze all minerals in the meteorite, the sections were carefully examined and photographed, and more than 400 mineral grains were selected for detailed analyses. Both sample and mineral standards were carbon-coated simultaneously to a uniform thickness. A 258 MICROSCOPIC EXAMINATIONSThe fine-grained dense meteorite contains about 80% silicates, 14% Fe-Ni metals and 6 percent troilite and other accessories (see Table 1). The meteorite is porphyritic with pheno...

Meteorites from the Lut Desert (Iran)

“…Despite its vast surface area (1.75 9 10 6 km 2 ) and dry climate, few meteorites were recorded until recently in Iran. Only two meteorites, both falls, were cataloged in the Meteoritical Bulletin during the 20th century: Veramin, a mesosiderite fallen in 1880 (Ward 1901;Graham and Hassanzadeh 1990) and Naragh, a H6 chondrite fallen in 1974 (Clarke 1975;Adib and Liou 1979). Shahdad, the first Iranian meteorite find, was collected in 2005 from the western margin of the Lut Desert (Garvie 2012).…”

The Famenin fall and other ordinary chondrites intermediate between H and L groups

“…Veramin mesosiderite (Graham & Hassanzadeh, 1990;Ward, 1901) and Naragh H6 chondrite (Adib & Liou, 1979;Clarke, 1975) in 1880 and 1974, respectively.…”

“…No record of related fireball sighting or atmospheric detonation sounds were reported. Only two meteorite falls have been recorded in Iran before Famenin: Veramin mesosiderite (Graham & Hassanzadeh, 1990; Ward, 1901) and Naragh H6 chondrite (Adib & Liou, 1979; Clarke, 1975) in 1880 and 1974, respectively.…”