BRAZIL - SP
It is a genomic breccia with the clasts and matrix of the same compositional group, but different petrological types, H4-5, S4, W0
C.V.N. Villaça and M.E. Zucolotto, MNRJ/UFRJ; D. Cunha, D. Atencio, IGc/USP). Polished thin sections were examined by MEV/EDS and electron microprobe. There are some black shock-induced melt veins, one broader crossing the entire thin section. Olivine, ortho and clinopyroxene were observed with abundant Fe-Ni-metal and sulfide. Mineralogy dominated by forsterite, enstatite, iron, troilite, and tetrataenite. Albite, chromite, diopside, augite, pigeonite, taenite, and merrillite are minor components. Texturally there are at least two lithologies. One exhibits an abundance of chondrules with well-defined margins and no visible plagioclase, consistent with petrologic type 4 chondrites. The other lithology displays chondrules with outlines blurring into the groundmass as evidence of an increasing recrystallization. In at least one clast some small plagioclase of about 20 µm confirmed a type-5 lithology. The presence of shock veins and large olivine with undulatory extinction, fractures and some weakly mosaicism infer a shock state S4.
(A.A. Tosi, Labsonda/UFRJ, A.L.R. Moutinho) Microprobe analysis yields: Type 4 - olivines (Fa19.3±0.4, PMD = 2.22, n = 30); low-Ca pyroxenes (Fs17.3±0.9Wo0.9±0.3, PMD = 9.16, n= 23); high-Ca pyroxene Fs10.4±2.6Wo28.3±11.5, PMD 29.2, n = 12. Type 5 - olivines (Fa18.9±0.4 PMD = 1.96, n = 45); low-Ca pyroxenes (Fs16.9±0.6 Wo1.6±0.9, PMD = 5.44, n = 19); high-Ca pyroxene Fs15.1±2.5Wo16.0±2.5, PMD 22.7 n = 7). Metal: iron (Ni = 6.15±0.32 wt.%, Co = 0.42±0.02 wt.%, n = 9), tetrataenite (Ni = 52.9±2.3 wt.%, Co = 0.09±0.08 wt.%, n = 3), taenite (Ni = 37.1 wt.%, Co = 0.12 wt.%, n = 1), troilite (Ni = 0.11±0.11 wt.%, n = 9) and chromite (Cr/(Cr+Al) = 0.928±0.003, n = 3). Cathodoluminescence also gives results comparable to breccia H4-5. (D. Atencio, D. Cunha, A. L. R. Moutinho, Laboratório de Microscopia Eletrônica/IGc/USP) SEM/EDS analysis yields: olivines (Fa19.6±1.1,PMD=9.9,n=6); low-Ca pyroxenes (Fs16.6±0.7Wo0.0±0.0, PMD=3.43, n=15). plagioclase (Ab83.0±2.0An12.2±1.3Or4.8±0.8, n=5). Metal: tetrataenite (Ni = 49.16 ± 2.75 wt.%, n = 3), troilite (Fe = 61.49 ± 1.66 wt.%, S = 37.46 ± 1.02 wt.%, n = 10) and chromite (Cr/(Cr+Al) = 0.85, n = 2).
It is a genomict breccia with the clasts and matrix from the same compositional group but different petrologic types, H4-5, S4, W0
M.E. Zucolotto, A. Tosi, MNRJ/UFRJ; D. Atencio, D. Cunha and A. Moutinho, IGc/USP
(D. Cunha, D. Atencio, A.L.R. Moutinho) On 9 December 2013, about 7:00 p.m. local time, a meteorite fell in the city of Parauapebas, located in the eastern part of Pará State, Brazil. A witness reported seeing the bolide traveling from NE to SW direction. A stone hit the roof of a house with a loud noise that was heard by the resident Mrs. Maria. She claims that a meteorite fragment hit and injured her right shoulder but her son says that she was hit only by roof debris. Her son, I. S. Lima, collected the stone on the roof. The stone broke in two pieces during the impact. One piece is lost but the other remaining 62 g piece was kept by Mrs. Maria for some years and then donated to the Institute of Geosciences, USP. Another 210.3 g oriented mass was observed to fall by other city residents while they were in front of their house. Meire C. Rosa, her husband Paulo T. Nunes, her mother Rosa C. Santos and neighbors heard loud thunder and a noise when the stone penetrated the wooden beam of their house, embedding itself in the ground. Meire immediately collected the stone and noticed it was still warm. In early 2018, she contacted Andre L.R. Moutinho, who was already part of the classification team of the 62 g fragment. The 210.3 g stone was purchased by Andre L. R. Moutinho.
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