The relation between chemical composition and paragenesis in the biotite micas of igneous rocks

Nockolds, S. R.

doi:10.2475/ajs.245.7.401

Cited by 119 publications

(48 citation statements)

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“…Their compositions correspond to those of biotites coexisting with pyroxene and amphibole (Nockolds, 1947) and are in accordance with the petrographic observations. Most of the granitoid rocks from the studied area contain Mg-biotite (Foster, 1960), but Fe-biotite is found in diorite, quartz-monzonite and quartz-monzodiorite.…”

Section: Biotitesupporting

confidence: 72%

Geochemistry of the Rio Espinharas hybrid complex, northeastern Brazil

Campos

Neiva

Nardi

2002

Lithos

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The Rio Espinharas pluton, northeastern Brazil, belongs to the shoshonitic series and consists mainly of syenogranite, quartz -monzonite and porphyritic quartz -monzonite, but diorite, quartz -monzodiorite, quartz -syenite and microsyenogranite also occur containing microgranular enclaves, except for the diorite. Most variation diagrams of rocks, amphiboles, biotites and allanites show linear trends, but K, Zr, Sr and Ba of rocks display curved scattered trends. The rocks ranging from diorite to syenogranite define a pseudo-errorchron and have similar REE patterns. Syenogranite and microsyenogranite are derived from two distinct pulses of granite magma with initial 87 Sr/ 86 Sr ratio of 0.7083 F 0.0003 and 0.7104 F 0.0007, respectively. Modelling of major and trace elements shows that the syenogranite evolved by fractional crystallization of plagioclase, microcline, edenite, biotite and titanite, whereas quartz -monzonite, porphyritic quartz -monzonite, quartz -monzodiorite and quartz -syenite resulted from simple mixing between an upper mantle-derived dioritic magma and the upper crust-derived syenogranite magma. Dioritic enclaves are globules of a mafic magma from the upper mantle. D

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Section: Biotitesupporting

confidence: 72%

Geochemistry of the Rio Espinharas hybrid complex, northeastern Brazil

Campos

Neiva

Nardi

2002

Lithos

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“…Químicamente, las biotitas del granito de Banabuiú se proyectan en la zona de transición entre el campo de las biotitas ferríferas y el de las siderofilitas (Foster, 1960). En el diagrama de Nockolds (1947), se sitúan en el campo de las biotitas que coexisten con moscovita, mientras que en el esquema de clasificación de Nachit et al (1985) muestran afinidades con las series alumino-potási-cas, lo que sugiere una procedencia cortical para el granito de Banabuiú ( fig. 4).…”

Section: Petrografía Y Química Mineralunclassified

Geología y geocronología U-Pb del granito de Banabuiú, Noreste de Ceará, Brasil

Lima¹,

Neto²,

Azevedo³

et al. 2010

Estud. geol.

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IntroducciónEl granito de Banabuiú es una de las numerosas intrusiones graníticas emplazadas en la Provincia Bororema (PB) durante el final de la Orogenia Brasiliense (~600 Ma). Los terrenos situados en el sector septentrional de esta Provincia fueron subdivididos por Fetter (1999), Fetter et al. (2000 = -12 to -26), suggesting that the parental magmas of the Banabuiú granite could have been produced by partial melting of similar crustal materials.

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“…Since the octahedral site in this biotite is overfilled by 0.263, it would appear that either Fe or Ti, probably Fe 3+, fills the remaining tetrahedral site (Guidotti, 1984, p. 432). Nockolds (1947) distinguished three fields for biotites in igneous rocks on the basis of A120 3, and he correlated high A1 in biotite with different mineral assemblages. According to him, biotites in igneous rocks which are associated with muscovite have higher A120 3 content than those biotites which are unaccompanied by any other mafic mineral or accompanied by hornblende, pyroxene, and/or olivine.…”

Section: Composition Of Biotite-phlogopitementioning

confidence: 99%

“…Metamorphic and igneous data are taken from Deer et al (1963). Field I = biotites associated with muscovite, II = biotite unaccompanied by other mafic minerals and III= biotite associated with amphibole, pyroxene or olivine (after Nockolds, 1947).…”

Section: Composition Of Biotite-phlogopitementioning

confidence: 99%

The biotite-phlogopite series in fenites from the Loe Shilman carbonatite complex, NW Pakistan

Mian

Bas

1987

Mineral. mag.

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The Loe Shilman carbonatite sheet complex comprises an extensive amphibole sovite which is intruded by minor biotite sovite and amphibole ankeritic carbonatite. The carbonatites have fenitized the country rocks to form a metasomatic zone c. 100 m wide of alternating mafic and felsic mica-bearing banded fenites which grade into slates and phyllites. Phlogopite-rich micas occur nearest to the carbonatite contact. The biotites occur in K-feldspar + albite _+ Na-amphibole ___ aegirine and _ phengite fenites produced by the intrusion of the early amphibole sovite. Aegirine buffered the iron distribution and the biotites became more magnesian. Veins cross-cutting the fenites consist of biotite and/or Ba-bearing K-feldspar, and are interpreted to result from solutions emanating from the biotite sovite. The ankeritic carbonatite is responsible for the formation ofphlogopite in the fenites in a c. 3 m wide zone adjacent to the carbonatite, and evidently are the result of fenitizing fluids rich in Mg. Chemical equations calculated to balance the reactions interpreted to have taken place in the fenites suggest that about 10% of the A1 and Si in the protolith was mobilized and moved towards the carbonatites during fenitization, and that the fenitizing solutions were strongly alkaline and oxidizing. K E Y w og D S: biotite, phlogopite, fenite, carbonatite, Loe Shilman, Pakistan.

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The relation between chemical composition and paragenesis in the biotite micas of igneous rocks

Cited by 119 publications

References 0 publications

Geochemistry of the Rio Espinharas hybrid complex, northeastern Brazil

Geochemistry of the Rio Espinharas hybrid complex, northeastern Brazil

Geología y geocronología U-Pb del granito de Banabuiú, Noreste de Ceará, Brasil

The biotite-phlogopite series in fenites from the Loe Shilman carbonatite complex, NW Pakistan

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