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SERRA DE MAGÉ
BRAZIL - PE
Serra de Magé is a cumulative eucrite of the clan known as HED, from the asteroid Vesta.
Moraes & Guimarães (1926), who described the meteorite for the first time, reported the presence of light green to dark green fusion crust and fine-grained interstitial texture. Duke & Silver (1967) referred to the Serra de Magé as a coarse-grained rock, exhibiting an equigranular texture and the gabbroic affinities. Then, Prinz et al. (1977c) pointed out that the meteorite shows a mosaic texture with medium to coarse grain, no indication of shock metamorphism and evidence of a cumulative, as suggested by the feldspar petrographic analysis. A planar orientation of plagioclase in Serra de Magé was also observed by Duke (1963). Source: Gomes & Keil (1980).
Serra de Magé essentially consists of plagioclase and pyroxene. Since the rock is relatively coarse and heterogeneous, proportions of the two minerals fluctuate considerably from sample to sample. Thus, Duke & Silver (1967) reported 56% plagioclase and 40% pyroxene, while Prinz et al. (1977c) reported 64% and 34% of plagioclase and pyroxene, respectively. Normative data published later by other authors include 58.6% plagioclase and 38.7% pyroxene. Plagioclase is calcium Ab4.8 An95.1 Or0.1, commonly twinned. Pyroxenes exhibit complex exhaustion characteristics and two optically homogeneous phases: hypersthene En53.8 Fs44.6 Wo1.6 as the host (82% vol.) and augite in four distinct habits from hyperstene and pigeonite grains. Source: Gomes & Keil (1980).
Serra de Magé is clearly of cumulative origin, based on its texture and the distribution of incompatible elements, as shown by the evident positive anomaly of the Eu. The high U-Rb ratio and the anortite content indicates that his parental body was, or relatively high in refractory elements or low in moderately volatile lithophiles. Low-pressure fusion experiments on eucrite-type meteorites, carried out by Stolper (1977), demonstrated that the Serra de Magé may have been formed from liquids produced by an extensive fractionation of advanced partial fusions from regions supplying eukritic liquids instead of liquids similar composition. On the other hand, Consolmagno & Drake (1977), using information collected by Stolper (1977), abundance of rare earth elements and some assumptions, concluded that the meteorite originated from accumulation from liquids produced by an extensive fractionation of pyroxene and plagioclase . A detailed investigation of the Serra de Magé pyroxene shows that it initially crystallized as pigeonite, but during the slow cooling, augite exhaustion and inversion to hyperstene occurred. A cooling rate of 4x10-4 ºC / year and a depth of approximately 5 km was estimated for the formation of the Serra de Magé. Source: Gomes & Keil (1980).
Not reported by the Meteoritical Bulletin Database. The report of the fall and the first description of the meteorite was carried out by Moraes & Guimarães (1926). Source: Gomes & Keil (1980).
The Serra de Magé meteorite fell on a morning on the first of October 1923, in the Serra of the same name in the State of Pernambuco, about 20 km from a town called Pesqueira. The meteorite descended from the sky in the form of a fireball and a great explosion followed by sounds similar to gunshots, lasting approximately three minutes. A rain of stones fell over an extensive area and at least fifty fragments, mostly five cm in diameter and some reaching 10 cm, were collected by the local population. In places close to the fall, such as Garanhuns and neighboring villages, windows were broken and objects fell to the ground. Description obtained in the documents of National Museum.
Todas as informações que não possuírem fonte especifica, foram extraídas do Meteoritical Bulletin Database.
Todas as imagens possuem direitos autorais.
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