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BRAZIL - SP
Equilibrated Ordinary Chondrite H4
The texture of the meteorite is chondritic, with chondrules varying in size from about 0.1-2 mm. The boundaries between matrix and cores are clear and well-defined. The internal textures of the chondrules vary considerably. The most common types are radiant pyroxenes, porphyritic chondrules, with olivine and pyroxene crystals in a microcrystalline matrix; barred olivine and glassy chondrules, with turbidity and mainly slightly birefringent glass. Conductor fragments are common and the matrix is transparent and microcrystalline. A major constituent is igneous glass. The minerals present are: olivine, bronzite, diopside, oligoclase, whitlockite, chlorapatite, kamacite, taenite (plessite), troilite, chromite, native copper, pentlandite, ilmenite, bravoite, mackinawita and chalcopyrite. (Source: Keil & Gomes, 1976).
Olivine (Fa I7.3), bronzite (Fs 16.5), diopside (Wo 45.3 En 49.0 Fs 5.7), oligoclase (Ou 5.4 Ab 84.1 An I0.4). The Fe / SiO and FeO / Fe ratios calculated (0.74 and 0.59, respectively) agree well with the classification, since Van Schmus and Wood's (1967) averages for group H chondrites are 0.77 and 0 , 63, respectively. Additional evidence for the classification of H group originates from the total iron content (27.15%), which is compatible with the value listed by Keil and Fredriksson (1964), 27.52%, for group H. chondrites ( Source: Keil & Gomes, 1976).
Based on chemical (mineral and global composition) and textural data, the Avanhandava meteorite is classified as an ordinary H4 chondrite.
The meteorite was described "by Arid and Rüegg (1965, 1969) and by Ramdohr (1973). (Source: Keil & Gomes, 1976). The meteorite was described in detail by Paar et al., (1976).
The meteorite fell on a day in April 1952 in Bairro do Borá, about 10 km from the city of Avanhandava, state of São Paulo. A simple rock weighing 9.33 kg, 40 cm long, was recovered from a 102 cm deep and 51 cm diameter hole by Mr Atushi Hirata. It looks like it was more than one fragment of the meteorite that fell. What the National Museum received has a polyhedral shape with a dark brown fusion crust and some lighter stains. A sample of the meteorite was on display for a while at a pharmacy in the region, and it is not known whether it was this sample or some other (or even a fragment of it) that would have gone to a college in Amparo. From this College, the sample would have gone to the National Museum, according to a letter from Hélio C. Chagas from 1958, the Colégio de Amparo had not yet received the sample that is believed to have gone to the Museum through exchange. Description given by M. E. Zucolotto.
Todas as informações que não possuírem fonte especifica, foram extraídas do Meteoritical Bulletin Database.
Todas as imagens possuem direitos autorais.
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