BRAZIL - MA
Equilibrated Ordinary Chondrite H5.
The meteorite has a chondritic texture with well-defined chondrites ranging from 0.3 to 1.5mm (average of 0.6mm). Different conductor textures were observed, including barred olivine, radial, porphyritic and granular pyroxene. Chondrules and chondrule fragments are embedded in a fine-grained microcrystalline matrix. Source: Gomes & Keil (1980).
Analysis by electron microprobe - Main minerals: olivine Fa 18.8, pyroxene with low Ca (bronzite) Fs 16.8 and metals such as kamacite and taenite. With less quantity, minerals such as plagioclase Ab81.7 An13.0 or5.3 and troilite. Accessory minerals such as diopside En49.2 Fs7.0 Wo43.8, chromite, native copper, pentlandite and whitlockite. Source: Gomes & Keil (1980).
Based on the mineralogical composition, particularly olivine and low Ca pyroxene, and chromite, it is concluded that the meteorite belongs to the chemical group H. Using the total chemistry data and the reasons such as Fe ° / Fe (9.89), Fe / SiO2 ( 0.83) and FeNi metal (21.07%) are also consistent with the H classification. Based on the uniformity and homogeneity of ferromagnesian minerals, the absence of fiery glass, and the degree of recrystallization of the matrix, the meteorite is classified as petrographic type 5 of Van Schmus and Wood (1967). Source: Gomes & Keil (1980).
Not reported by the Meteoritical Bulletin Database. Listed by Derby (1888a, b) Oliveira (1931), Vidal (1936), Hey (1966) and with full description given by Gomes et al., 1977a.
The Itapicuru Mirim meteorite, in Maranhão, fell in the morning (11 am) on a clear day in March 1879. The fall was accompanied by sound effects (gunshots) and a single stone was recovered. Source: Gomes & Keil (1980).
All information that does not have a specific source was extracted from the Meteoritical Bulletin Database.
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