Caldasite Explained

Caldasite
Alternative Name:	Zircon-favas
Composition:	Zircon (ZrSiO4), Baddeleyite (ZrO2)
Composition Secondary:	Uranium (as triuranium octoxide [U<sub>2</sub>O<sub>3</sub>])

Caldasite is a rare uraniferous ore of zirconium found in the Poços de Caldas massif, located in the states of Minas Gerais and São Paulo, Brazil.

It is most often found as a dark gray, very dense, hard rock. It also appears as a friable brown substance.^[1]

The massif is an alkaline complex, formed by a large intrusion during the mid-Cretaceous. The ore is a result of hydrothermal alteration of the nepheline-syenitic rocks; it has also been weathered out and concentrated in paleoplacer deposits.

Further reading

• Master's . Aproveitamento do Zircônio e do Urânio de um Mineral Complexo de ZrSiO₄ e ZrO₂ (Caldasito), da Região de Poços de Caldas, Estado de Minas Gerais, Brasil . Reclaiming Zirconium and Uranium from a ZrSiO₄–ZrO₂ Compound Mineral (Caldasite), Poços de Caldas Region, Minas Gerais, Brazil . A.E.P. . Brown . 1972 . São Paulo Polytechnic University . pt . January 27, 2016 .
• Brown. A.E.P.. Costa. E.C.. Processing of a uraniferous zirconium ore. 1972. 4073530.
• Curtius . A.J. . 1975 . Radioactive disequilibria in Brazilian caldasite . Inorganic and Nuclear Chemistry Letters . 11 . 12 . 841–845 . January 27, 2016 . 0020-1650 . 10.1016/0020-1650(75)80111-5.
• January 1887 . Derby . O.A. . On Nepheline-Rocks in Brazil, with Special Reference to the Association of Phonolite and Foyaite . Quarterly Journal of the Geological Society . London . 43 . 1–4 . 457–473 . 10.1144/GSL.JGS.1887.043.01-04.35 . January 28, 2016 .
• Poços de Caldas and Itataia: two case histories of uranium exploration in Brazil . J.M.A. . Forman . A.G. . Angeiras . 26–29 November 1979 . Advisory Group Meeting . Proceedings of an advisory group meeting on case histories of uranium exploration . International Atomic Energy Agency . Vienna . 99–139 . IAEA-AG-250/14 . 92-0-141081-6 . 2016-01-28 .
• Franco . R.R. . Loewenstein . W. . 1948 . Zirconium from the region of Poços de Caldas . American Mineralogist . 33 . 3–4 . 142–151 . January 27, 2016 .
• Book: Laznicka, P. . Empirical Metallogeny, Depositional Environments, Lithologic Associations and Metallic Ores. Phanerozoic Environments, Associations and Deposits . 28 January 2016 . 1985 . Elsevier . 978-0-444-59756-4 . 1531 .
• Takenaka. L.B.. Lana. C.. Scholz. R.. Nalini Jr.. H.A.. de Abreu. A.T.. Optimization of the in-situ U–Pb age dating method via LA-Quadrupole-ICP-MS with applications to the timing of U–Zr–Mo mineralization in the Poços de Caldas Alkaline Complex, SE Brazil. Journal of South American Earth Sciences. October 2015. 62. 70–79. 10.1016/j.jsames.2015.04.007.
• Book: Tolbert, G.E. . The Uraniferous Zirconium Deposits of the Poços de Caldas Plateau, Brazil . USGS Bulletin . 1185-C . 30 January 2016 . 1966 . 10.3133/b1185C .
• Ulbrich . H.H.G.J. . 1984 . A Petrografia, a Estrutura e o Quimismo de Nefelina Sienitos do Maciço Alcalino de Poços de Caldas MG-SP . Petrography, Structure and Chemistry of the Nepheline Syenite Poços de Caldas Alkaline Massif . Habilitation . pt . Instituto de Geociências, University of São Paulo . 2016-01-28.
• Ulbrich. H.H.G.J.. Vlach. S.R.F.. Ulbrich. M.N.C.. Kawashita. K.. Penecontemporaneous syenitic-phonolitic and basic-ultrabasic- carbonatitic rocks at the Poços de Caldas alkaline massif, SE Brazil: Geologic and geochronologic evidence. Revista Brasileira de Geociências (Now Brazilian Journal of Geology). March 2002. 32. 1. 15–26. 8 February 2016. 2317-4692. https://web.archive.org/web/20160311031611/http://rbg.sbgeo.org.br/index.php/rbg/article/viewFile/957/649#. 2016-03-11. dead.
• Book: Ulbrich . H.H.G.J. . Vlach . S.R.F. . Demaiffe . D. . Ulbrich . M.N.C. . Structure and origin of the Poços de Caldas Alkaline Massif, SE Brazil . P. . Comin-Chiaramonti . C.B. . Gomes . Mesozoic to Cenozoic Alkaline Magmatism in the Brazilian Platform . https://books.google.com/books?id=9dbX6WKPsvsC&pg=PA367 . 2005 . Edusp/Fapesp . São Paulo . 978-85-314-0903-5 . 367–418 . 2016-01-30 .

Notes and References

1. Gonçalves. J.R.. Lakschevitz Jr.. A.. Study of the mineral characteristics of caldasite. INIS. International Nuclear Information System. 8 February 2016. pt. August 1973 . INIS-MF--1563.