| Texto completo | |
| Autor(es): Mostrar menos - |
Menezes Filho, Luiz A. D.
[1]
;
Chaves, Mario L. S. C.
[1]
;
Chukanov, Nikita
[2]
;
Atencio, Daniel
[3]
;
Scholz, Ricardo
[4]
;
Pekov, Igor
[5]
;
da Costa, Geraldo Magela
[6]
;
Morrison, Shaunna M.
[7]
;
Andrade, Marcelo B.
[8]
;
Freitas, Erico T. F.
[9]
;
Downs, Robert T.
[7]
;
Belakovskiy, Dmitriy I.
[10]
Número total de Autores: 12
|
| Afiliação do(s) autor(es): | [1] Univ Fed Minas Gerais, Inst Geociencias, Dept Geol, Ave Antonio Carlos 6627, BR-31270901 Belo Horizonte, MG - Brazil
[2] Russian Acad Sci, Inst Problems Chem Phys, Chernogolovka 142432, Moscow Region - Russia
[3] Univ Sao Paulo, Inst Geociencias, Rua Lago 562, BR-05508080 Sao Paulo - Brazil
[4] Univ Fed Ouro Preto, Escola Minas, Dept Geol, Campus Morro do Cruzeiro, BR-35400000 Ouro Preto, MG - Brazil
[5] Moscow MV Lomonosov State Univ, Fac Geol, Moscow 119991 - Russia
[6] Univ Fed Ouro Preto, Inst Cieneias Exatas & Biol, Dept Quim, Campus Morro do Cruzeiro, BR-35400000 Ouro Preto, MG - Brazil
[7] Univ Arizona, Dept Geosci, 1040 E 4th St, Tucson, AZ 85721 - USA
[8] Univ Sao Paulo, Sao Carlos Inst Phys, POB 369, BR-13560970 Sao Carlos, SP - Brazil
[9] Univ Fed Minas Gerais, Ctr Microscopia, Ave Antonio Carlos 6627, BR-31270901 Belo Horizonte, MG - Brazil
[10] Russian Acad Sci, Fersman Mineral Museum, Leninskiy Prospekt 18-2, Moscow 119071 - Russia
Número total de Afiliações: 10
|
| Tipo de documento: | Artigo Científico |
| Fonte: | MINERALOGICAL MAGAZINE; v. 82, n. 1, p. 133-144, FEB 2018. |
| Citações Web of Science: | 4 |
| Resumo | |
Parisite-(La) (IMA2016-031), ideally CaLa2(CO3)(3)F-2, occurs in a hydrothermal vein crosscutting a metarhyolite of the Rio dos Remedios Group, at the Mula mine, Tapera village, Novo Horizonte county, Bahia, Brazil, associated with hematite, rutile, almeidaite, fluocerite-(Ce), brockite, monazite-(La), rhabdophane-(La) and bastnasite-(La). Parisite-(La) occurs as residual nuclei (up to 5 mm) in steep doubly-terminated pseudo-hexagonal pyramidal crystals (up to 8.2 cm). Parisite-(La) is transparent, yellow-green to white, with a white streak and displays a vitreous (when yellow-green) to dull (when white) lustre. Cleavage is distinct on pseudo-[001]; fracture is laminated, conchoidal, or uneven. The Mohs hardness is 4 to 5, and it is brittle. Calculated density is 4.273 g cm(-3). Parisite-(La) is pseudo-uniaxial (+), omega = 1.670(2) and epsilon = 1.782(5) (589 nm). The empirical formula normalized on the basis of 11 (O + F) atoms per formula unit (apfu) is Ca0.98(La0.83Nd0.51Ce0.37Pr0.16Sm0.04Y0.03)(Sigma 1.94)C3.03O8.91F2.09. The IR spectrum confirms the absence of OH groups. Single-crystal X-ray studies gave the following results: monoclinic (pseudo-trigonal), space group: C2, Cm, or C2/m, a = 12.356(1) angstrom, b = 7.1368(7) angstrom, c = 28.299(3) angstrom, beta = 98.342(4)degrees, V = 2469.1(4) angstrom(3) and Z = 12. Parisite-(La) is the La-dominant analogue of parisite-(Ce). (AU) | |
| Processo FAPESP: | 14/50819-9 - SoS RARE: multidisciplinary research towards a secure and environmentally sustainable supply of critical rare earth elements (Nd and HREE) |
| Beneficiário: | Daniel Atencio |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |
| Processo FAPESP: | 13/03487-8 - Centro de caracterização de novas espécies minerais: espectroscopia Raman, difração por raios X e nêutrons, e microssonda eletrônica |
| Beneficiário: | Marcelo Barbosa de Andrade |
| Modalidade de apoio: | Auxílio à Pesquisa - Jovens Pesquisadores |