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Conceicao do Tocantins
Basic information Name: Conceicao do Tocantins
     This is an OFFICIAL meteorite name.
Abbreviation: There is no official abbreviation for this meteorite.
Observed fall: No
Year found: 2021
Country: Brazil
Mass:help 449 g
Meteoritical Bulletin:  MB 111  (2023)  Iron, IIAB
Recommended:  Iron, IIAB    [explanation]

This is 1 of 151 approved meteorites classified as Iron, IIAB.   [show all]
Search for other: IIAB irons, Iron meteorites, and Metal-rich meteorites
Comments: Approved 29 Jan 2022
Writeup from MB 111:

Conceicao do Tocantins        12°11’S, 47°16’W

Tocantins, Brazil

Find: 2020 Oct

Classification: Iron meteorite (IIAB)

History: (Gabriel Gonçalves, USP, and André L. R. Moutinho) The meteorite was found by a gold miner on a farm in the rural area of Conceição do Tocantins, state of Tocantins, when looking for gold with a metal detector in October 2020. The meteorite was buried at a depth of approximately 30 cm. The gold prospector’s sister-in-law posted pictures of the "stone" on social media page and was first noticed by Gabriel Gonçalves. Sample was sent to A.L.R. Moutinho who confirmed it as a meteorite.

Physical characteristics: A regular weatheread mass weighing 449 g and measuring ~79 × 52 × 32 mm

Petrography: (Andre L. R. Moutinho) The meteorites has suffered weathering and no fusion crust was observed. A polished etched slice measuring 56 × 32 mm shows a structureless surface typical of hexahedrites with numerous plate-shaped and prismatic rhabdites. Many rhabdites are surrounded by oxide. Schreibersite is also found around troilite nodules. Kamacite shows shock twinning features known as Neumann lines. A troilite nodule inclusion (5 × 2 mm) was observed. A heat zone region was observed on one side of the slice.

Geochemistry: ICP-MS data, using a sample of North Chile (Filomena) as standard (Chris Herd and Patrick Hill, UAb) ICP-MS method: Ni = 53.8, Co = 4.5 (both mg/g); Cr = 129, Ir = 6.12, Ga = 57.21, Ge = 148.3, As = 5.33, Pt = 26.6, Cu = 137.11, W = 2.603, Pd = 0.55, Ag = 0.002, (all µg/g). (Margareth. S. Navarro, Jacinta Enzweller, and Alvaro P. Crósta, DGRN/UNICAMP). LA-ICP-MS method: Ni = 54.58, Co = 4.40 (both mg/g); Cr = 37, Ir = 7.5, Ga = 62, Ge = 147, As = 2.5, Pt = 25.4, Cu = 156, Au = 0.50, W = 3.0, Pd = 1.6, Ag = 0.10, Os = 2.4 (all µg/g). (Ricardo Scholz and Gláucia N. Queiroga, DEGEO/EM/UFOP). EPMA: kamacite 5.65 % Ni, 0.46 % Co.

Classification: Iron, IIAB. Similar to Arraias but resolvable based on Ir and Os content. Type is consistent with the analysed structure.

Specimens: Main mass with A.L.R. Moutinho, 21.6 g at UNICAMP

Data from:
  Table 0
  Line 0:
Origin or pseudonym:field
Date:2020 Oct
Mass (g):449
Class:Iron, IIAB
Classifier:C. Herd and P. Hill, Uab. A. P. Crosta, Unicamp. G. Gonçalves, USP and A. L. R. Moutinho
Type spec mass (g):21.6
Type spec location:UNICAMP
Main mass:Andre L R Moutinho
Finder:L.M. Souza
Comments:Submitted by A.P. Crosta, G. Gonlçaves and A.L.R. Moutinho
   and collections
UAb: 1-26 Earth Sciences Building, University of Alberta, Edmonton, AB, T6G 2E3, Canada, Canada; Website (institutional address; updated 17 Oct 2011)
USP: Museu de Geociências - USP Rua do Lago, 562 CEP: 05508-080 Butantã - SP Brazil, Brazil; Website (institutional address; updated 16 Feb 2024)
UNICAMP: Institute of Geosciences Minerals Collection Rua Carlos Gomes 250 Cidade Universitária Zeferino Vaz Campinas, SP 13083-855, Brazil; Website (institutional address; updated 17 Dec 2021)
References: Published in Gattacceca J., McCubbin F. M., Grossman J. N., Schrader D. L., Chabot N. L., D’Orazio M., Goodrich C., Greshake A., Gross J., Joy K. H., Komatsu M. and Miao B. (2023) The Meteoritical Bulletin, No. 111. Meteoritics & Planetary Science 58, 901–904. ?
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Public domain photographs:
Alvaro P. Crosta         

     Recommended::   (12° 11'S, 47° 16'W)

     This is 1 of 2 approved meteorites from Tocantins, Brazil (plus 1 impact crater)
     This is 1 of 88 approved meteorites from Brazil (plus 6 unapproved names) (plus 7 impact craters)
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