Composition of monazites from pegmatites in eastern Minas Gerais, Brazil

Murata, K. J.; Dutra, C. V.; Costa, Mana; Branco, J.J.R.

doi:10.1016/0016-7037(59)90043-2

Cited by 23 publications

(6 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The REE distribution in our sample deserves a comment. A ll monazite-type minerals have in vari ably high ceric REE distribution (Pabst and Hutton, 1951;Murata et al, 1953Murata et al, , 1958Lee and Bastron, 1967;Fleischer and Altschuler, 1969;Bowles et al, 1980;Fleischer and Rosenblum, 1990). This is also the case for the monazites from Latium (Gottardi, 1952; this work) and all the A lp in e monazites (Mannucci et ai, 1986; Demartin et a ly 1991), in clu d in g the 'anomalous' sample fro m Piona (Gramaccioli and Segalstad, 1978).…”

Section: Resultssupporting

confidence: 58%

Monazite-huttonite solid-solutions from the Vico Volcanic Complex, Latium, Italy

et al. 1996

View full text Add to dashboard Cite

The crystal-chemical relationships occurring within a single grain of monazite-(Ce) from Vetralla, Vico Volcanic Complex, north of Rome, are outlined. The sample is from a miarolitic cavity in a holocrystalline ejectum consisting of K-feldspar plus minor plagioclase, mica and Fe-oxides, collected from a pyroclastic explosive level. The Gandolfi film (Cu-K alpha radiation) can be indexed in space group P2(1)/n with a = 6.816(4); b = 6.976(4); c = 6.471(3) Angstrom; beta = 103.63(3)degrees; V = 299.0(6) Angstrom(3). Electron-probe microanalyses plot within the field of monazite along the huttonite-monazite edge of the huttonite-monazite-brabantite triangle. Despite patchy and irregular zoning, the grain shows a clear enrichment towards pure monazite at the outer rim. A constant Th:Si ratio of 1:1 indicates the existence of a simple solid-solution between huttonite and monazite. The substitution can be written as Th4+ + Si4+ --> REE(3+) + P5+ without requiring any electrostatic compensation by divalent cations, or by anionic groups. The REE distribution pattern is compatible with that of monazites from syenitic rocks

show abstract

Section: Resultssupporting

confidence: 58%

Monazite-huttonite solid-solutions from the Vico Volcanic Complex, Latium, Italy

et al. 1996

View full text Add to dashboard Cite

show abstract

“…Murata et al (1958) e Marciano (1995) analisaram amostras de pegmatitos graníticos da "Província Pegmatítica Oriental do Brasil", situada a leste da Serra do Espinhaço em Minas Gerais. As médias desses dados constam na tabela 2, juntamente com os espécimes "primários", isto é, cristalizados em rochas graníticas da mesma província (Nalini Jr. 1997), fornecendo-se ainda uma comparação com as médias das análises apresentadas nesse trabalho.…”

Section: Depósitos Estudadosunclassified

“…Entretanto, tais análises individualmente encontram-se espalhadas ao longo da linha de concórdia. As idades de Marciano 1995);7 -Pegmatito Mar de Espanha (Kato 1958, in Murata et al 1958; 8,9 -Granitos Urucum e Palmital (Nalini Jr. et al 1996, Nalini Jr. 1997; 10 -Greisen do depósito Bom Futuro -Rondônia (Souza et al 2005); 11 -Ortognaisse Jamari -Rondônia (Souza et al 2006);12,13,14/15 -Veios hidrotermais em Alinci, ex-Iugoslávia (Bermanec et al 1988); Liguria Central, Itália (Cabella et al 2001); e Montes Urais, Rússia,representando (14/15) respectivamente sistemas não alterados e alterados em hidrotermalismo pós-tumo (Repina 2008 Diamantina (Fig. 4-A), e entre 465 e 425 Ma com média ponderada de 444 ±4 Ma nas amostras de Olhos d'Água (Fig.…”

Section: Depósitos Estudadosunclassified

Monazita em veios de quartzo da Serra do Espinhaço Meridional (MG): mineralogia, idades LA-ICP-MS e implicações geológicas

Chaves

Brandão

Bühn

2010

RBG

View full text Add to dashboard Cite

Resumo Com a descoberta de ocorrências de monazita num ambiente geológico incomum, em veios de quartzo na Serra do Espinhaço Meridional, propôs-se estudar a geologia desses depósitos e seus comportamentos químicos em três localidades (Buenópolis, Olhos d'Água e Diamantina), bem como datações geocronoló-gicas U-Pb por abrasão a laser MC-ICP-MS foram efetuadas em amostras de Diamantina e Olhos d'Água. Em Buenópolis, o mineral aparece como indivíduos geminados, em cascalheiras coluvionares na zona de contato do Grupo Macaúbas com o Supergrupo Espinhaço. Na ocorrência de Olhos d'Água, têm sido registrados grandes cristais em bolsões ovalados métricos, hospedados em metapelitos do Grupo Macaúbas. Em Diamantina, foram estudados cristais milimétricos de um depósito coluvionar do Rio Caeté-Mirim. Certamente, no primeiro e no terceiro casos, tais grãos se originaram dos abundantes veios de quartzo que seccionam as seqüências regionais. Análises com microssonda eletrônica mostraram valores de óxidos em geral semelhantes para os três depósitos, entretanto com certas particularidades. As amostras foram caracterizadas como monazitas-(Ce), localmente ricas em neodímio e, embora em geral não tenham revelado semelhanças absolutas para dois depó-sitos, Diamantina e Olhos d'Água apresentaram alguns aspectos químicos preferenciais. Os resultados U-Pb indicaram, supondo-se as idades mais antigas (~491 Ma) como de cristalização do mineral, uma extensão completa de idades na faixa entre 490 e 440 Ma, provavelmente devidas a reaquecimentos tardios. Em termos geotectônicos, tais idades permitem evidenciar as últimas manifestações referentes ao Ciclo Brasiliano na região.Palavras-chave: monazita-(Ce), Serra do Espinhaço, química mineral, geocronologia. Abstract Monazite in quartz-veins from the Southern Espinhaço Range (MG): mineralogy, LA-ICP-MS ages and geological implications.Due to the discovery of monazite occurrences in an uncommon geologic setting, in quartz veins cutting rocks of the Southern Espinhaço Range, a study was carried out on the geology and mineral chemistry of these deposits in three localities (Buenópolis, Olhos d'Água and Diamantina), as well as to make U-Pb laser ablasion MC-ICP-MS geochronological determinations in the Diamantina and Olhos d'Água samples. In Buenópolis, monazite specimens are common as twin crystals, occurring in colluvial gravel deposits in a contact zone between the Espinhaço Supergroup with the Macaúbas Group. The Olhos d'Água occurrence is in metric oval-shaped pockets hosted in metapelitic rocks of the Macaúbas Group, where large crystals have been discovered. In Diamantina, millimeter-size crystals were studied as broken grains recovered in a colluvial deposit near the Caeté-Mirim river. Certainly in the first and in the third cases, such grains came from the abundant regional quartz veins. Electron microprobe analyses showed similar oxide values for the three deposits, but with some chemical specific aspects. The samples have been identified as monazites-(Ce), locally Nd-rich; the Diamanti...

show abstract

“…In fact, under such conditions, xenotime is likely to be overlooked entirely, particularly if its tenor is low. A good test for its presence is to examine carefully the ilmenite fraction, where xenotime may be found accompanied Murata, Dutra, Da Costa, and Branco, 1958, Murata, Rose, and Carron, 1953, Murata, Rose, Carron, and Glass, 1957_____________________ Vainshtein, Tugarinov, and Turan skaya, 1956_____________ Wylie, 1950_______________________ Lindsay Chemical Co. 1956 0.9 0.9 1.4 by little or no monazite. The presence of xenotime in the monazite fraction may also be detected by the optical method of Murata and Bastron (1956).…”

Section: Monazite and Xenotimementioning

confidence: 99%

Monazite in the granitic rocks of the southeastern Atlantic States: An example of the use of heavy minerals in geologic exploration

Mertie¹

1979

Professional Paper

View full text Add to dashboard Cite

_________________________________________ Introduction ___________________________ Early work __________________________________ Present investigation _________________ Purpose of study _____________________________ Acknowledgment ___________________ Field conditions and methods ______________________ Saprolite ____________________________________ Use of accessory minerals ____________ Panning ______________________ Field processing of panned concentrates ____ Classification of granitic rocks proposed for weathered regions ______________ Nomenclature ___________________ Chemical composition _____________ Accessory minerals __________________ Stability and genetic significance __________ Mineralogical criteria relating to the origin of granitic rocks ____________________ Preservation of inherited characteristics ____ Variations in physical properties ___________ Unusual tenor for all accessory minerals Unusual tenor for one or two accessory minerals _________________ Anomalous amounts and composition of the iron ores _________________ Regional variation of accessory minerals and petrographically anomalous min erals ______________________

show abstract

Composition of monazites from pegmatites in eastern Minas Gerais, Brazil

Cited by 23 publications

References 14 publications

Monazite-huttonite solid-solutions from the Vico Volcanic Complex, Latium, Italy

Monazite-huttonite solid-solutions from the Vico Volcanic Complex, Latium, Italy

Monazita em veios de quartzo da Serra do Espinhaço Meridional (MG): mineralogia, idades LA-ICP-MS e implicações geológicas

Monazite in the granitic rocks of the southeastern Atlantic States: An example of the use of heavy minerals in geologic exploration

Contact Info

Product

Resources

About