The Vicência meteorite, a stone of 1.547 kg, fell on September 21, 2013, at the village Borracha, near the city of Vicência, Pernambuco, Brazil. It was recovered immediately after the fall, and our consortium study showed it to be an unshocked (S1) LL3.2 ordinary chondrite. The LL group classification is based on the bulk density (3.13 g cm À3 ); the chondrule mean apparent diameter (0.9 mm); the bulk oxygen isotopic composition (d 17 O = 3.768 AE 0.042&, d 18 O = 5.359 AE 0.042&, D 17 O = 0.981 AE 0.020&); the content of metallic Fe,Ni (1.8 vol%); the Co content of kamacite (1.73 wt%); the bulk contents of the siderophile elements Ir and Co versus Au; and the ratios of metallic Fe 0 /total iron (0.105) versus total Fe/Mg (1.164), and of Ni/ Mg (0.057) versus total Fe/Mg. The petrologic type 3.2 classification is indicated by the beautifully developed chondritic texture, the standard deviation (~0.09) versus mean Cr 2 O 3 content (~0.14 wt%) of ferroan olivine, the TL sensitivity and the peak temperature and peak width at half maximum, the cathodoluminescence properties of chondrules, the content of trapped 132 Xe tr (0.317 9 10 À8 cm 3 STP g À1 ), and the Raman spectra for organic material in the matrix. The cosmic ray exposure age is~72 Ma, which is at the upper end of the age distribution of LL group chondrites. The meteorite is unusual in that it contains relatively large, up to nearly 100 lm in size, secondary fayalite grains, defined as olivine with Fa >75 , large enough to allow in situ measurement of oxygen and Mn-Cr isotope systematics with SIMS. Its oxygen isotopes plot along a mass-dependent fractionation line with a slope of~0.5 and D 17 O of 4.0 AE 0.3&, and are similar to those of secondary fayalite and magnetite in the unequilibrated chondrites EET 90161, MET 96503, and Ngawi. These data suggest that secondary fayalite in Vicência was in equilibrium with a fluid with a D 17 O of~4&, consistent with the composition of the fluid in equilibrium with secondary magnetite and fayalite in other unequilibrated ordinary chondrites. Secondary fayalite and the chondrule olivine phenocrysts in Vicência are not in isotopic equilibrium, consistent with low-temperature formation of fayalite during aqueous alteration on the LL parent body. That alteration, as dated by the 53 Mn-53 Cr chronology age of secondary fayalite, took place 4:0 þ1:4 À1:1 Ma after formation of CV CAIs when anchored to the quenched angrite D'Orbigny.
Serra Pelada is the newest Brazilian eucrite and the first recovered fall from Amazonia (State of Pará, Brazil, June 29 th 2017). In this paper, we report on its petrography, chemistry, mineralogy and its magnetic properties. Study of four thin sections reveals that the meteorite is brecciated, containing basaltic and gabbroic clasts, as well of recrystallized impact melt, embedded into a fine-medium grained matrix. Chemical analyses suggest that Serra Pelada is a monomict basaltic eucritic breccia, and that the meteorite is a normal member of the HED suite. Our results provide additional geological and compositional information on the lithological diversity of its parent body. The mineralogy of Serra Pelada consists basically of low-Ca pyroxene and high-Ca plagioclase with accessory minerals such as quartz, sulphide (troilite), chromite -ulvöspinel and ilmenite. These data are consistent with the meteorite being an eucrite, a basaltic achondrite and a member of the howardite-eucrite-diogenite (HED) clan of meteorites which most likely are from the crust asteroid 4 Vesta.Key words: Serra Pelada, meteorite, eucrite, Vesta, Brazilian Meteorite.
The Parauapebas meteorite, third official meteorite discovered in the Brazilian Amazon region, is a "hammer meteorite" which fell on December 9 th , 2013, in the city of Parauapebas, Pará State, Brazil. Mineralogy is dominated by forsterite, enstatite, iron, troilite, and tetrataenite. Albite, chromite, diopside, augite, pigeonite, taenite, and merrillite are minor components. Two main clasts are separated by black shock-induced melt veins. One clast exhibits an abundance of chondrules with well-defined margins set on a recrystallized matrix composed mostly of forsterite and enstatite, consistent with petrologic type 4 chondrites. The other clast displays chondrules with outlines blurring into the groundmass as evidence of increasing recrystallization, consistent with petrologic type 5 chondrites. The clasts of petrologic type 4 have a fine-grained texture compared to those of type 5. It is a genomict breccia (indicated by shock melt veins) with the clasts and matrix of the same compositional group, but different petrologic types, H4 and H5. The melted outer crust of the Parauapebas meteorite is comprised of forsterite with interstitial dendritic iron oxide, and is rich in irregular vesicles, which are evidence of the rapid formation of the crust. The type specimen is deposited in the Museum of Geosciences of the University of São Paulo, Brazil.
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