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Montes Claros de Goias
Basic information Name: Montes Claros de Goias
     This is an OFFICIAL meteorite name.
Abbreviation: There is no official abbreviation for this meteorite.
Observed fall: No
Year found: 2018
Country: Brazil
Mass:help 14.92 kg
Classification
  history:
Recommended:  H5    [explanation]

This is 1 of 10132 approved meteorites (plus 18 unapproved names) classified as H5.   [show all]
Search for other: H chondrites, H chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 11 Nov 2020
Writeuphelp
Writeup from MB 109:

Montes Claros de Goias        15°45’46.53"S, 51°31’1.75"W

Goias, Brazil

Find: 2018 Sept

Classification: Ordinary chondrite (H5)

History: (Andre L R Moutinho,Carlo Bottelli) In September 2018, Dione Pantaleão, a manager of the Corrego Mestre farm located ~30 km northwest of Montes Claros de Goias city, Goias State, noticed a large stone in an area without any other rocks. In May 2019, the large and unusually heavy specimen was shown to the farm’s owner, Eduardo F. de Melo, who then contacted the meteorite collector Carlo Bottelli to seek assistance in identifying the possible meteorite. In July 2019, Bottelli and Eduardo took the meteorite to an astronomy meeting (5º Encontro Paulista de Astronomia - Sertaozinho, São Paulo), where its authenticity was confirmed by Andre L R Moutinho and Maria Elizabeth Zucolotto.

Physical characteristics: Single stone with a mass of 14.915 kg measuring approximately 31.5 × 21 × 16 cm and showing few regmaglypts. Bulk density 3.589 g/cm3

Petrography (M. E. Zucolotto, MN/UFRJ): Two thin sections were analyzed. Chondrules are not well defined. Chondrules, with apparent diameter ranging from 0.5 to 1.5 mm (mean 0.7 mm) set in medium grained matrix consisting of orthopyroxene, olivine, plagioclase and minor clinopyroxene. The major pyroxene crystals in the whole section are orthopyroxenes. Olivine show undulatory extinction, planar fractures and mosaicism. The meteorite shows thin melt veins, some of them with small melt pockets and presence of melted metal and troilite flakes. Opaque phases are represented by Fe,Ni alloys (alpha and gamma) and sulphides both in chondrules and in the matrix. Neumann lines can be seen on many large kamacite crystals and around 20 to 30% of the metal has already been oxidized. This generates an orange to brown staining on the silicate phase also many fractures filled with oxide. The presence of feldsphatic, chromite and phosphate grains up to 100 μm in size.

Geochemistry: Electron microprobe analysis yielded (A. Tosi, IGEO/UFRJ): olivine Fa18.6±0.6 (18), low-Ca pyroxene Fs16.7±0.6En82.2±0.7Wo1.1±0.5 (17), high-Ca pyroxene Fs12.9±2.8En65.1±0.7Wo22.0±8.1 (5); plagioclase Ab80.4±2.1An12.2±1.2Or7.5±1.2 (10), Co in kamacite 0.46±0.02 (30).

Classification: H5, weathering (W2) and moderately shocked (S4) ordinary chondrite.

Specimens: Main mass with finder; two polished thin sections and 25 g at MNRJ; AMoutinho: (2 pcs) 110 g; Carlo Bottelli: (4 pcs) 104 g; Rodrigo Guerra (1 pc) 4.8 g

Data from:
  MB109
  Table 0
  Line 0:
State/Prov/County:Goias
Origin or pseudonym:Farm
Date:2018 Sept
Latitude:15°45'46.53"S
Longitude:51°31'1.75"W
Mass (g):14915
Pieces:1
Class:H5
Shock stage:S4
Weathering grade:W2
Fayalite (mol%):18.6±0.6 (n=18)
Ferrosilite (mol%):16.7±0.6 (n=17)
Wollastonite (mol%):1.1±0.5
Classifier:M.E. Zucolotto, MN/UFRJ and A.A.Tosi, IGEO/UFRJ
Type spec mass (g):25
Type spec location:MNRJ
Main mass:Finder
Finder:Dione Pantaleao
Comments:Submitted by A. Moutinho and A. Tosi; submitted by Andre L. R. Moutinho and A. Tosi
Institutions
   and collections
MNRJ: Museu Nacional, Quinta da Boa Vista, Rio de Janeiro, CEP 20940-040, Brazil (institutional address; updated 26 Dec 2011)
AMoutinho: Andre Moutinho, Brazil; Website (institutional address; updated 17 Sep 2018)
Catalogs:
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
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Geography:

Brazil
Coordinates:
     Recommended::   (15° 45' 47"S, 51° 31' 2"W)

Statistics:
     This is 1 of 8 approved meteorites from Goias, Brazil
     This is 1 of 79 approved meteorites from Brazil (plus 6 unapproved names) (plus 7 impact craters)
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