Discrimination between primary magmatic biotites, reequilibrated biotites and neoformed biotites

Nachit, H.; Ibhi, Abderrahmane; Abia, El Hassan; Ohoud, Mohcine Ben

doi:10.1016/j.crte.2005.09.002

Cited by 360 publications

(150 citation statements)

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“…3a). It is almost (Nachit et al 2005). A -domain of primary magmatic biotites, B -domain of reequilibrated biotites, C -domain of neoformed biotites.…”

Section: Petrographical and Geochemical Characteristics Of Granitoidsmentioning

confidence: 99%

Biotite from Čierna hora Mountains granitoids (Western Carpathians, Slovakia) and estimation of water contents in granitoid melts

Bónová¹,

Broska²,

Petrík³

2010

Geologica Carpathica

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“…3a). It is almost (Nachit et al 2005). A -domain of primary magmatic biotites, B -domain of reequilibrated biotites, C -domain of neoformed biotites.…”

Section: Petrographical and Geochemical Characteristics Of Granitoidsmentioning

confidence: 99%

Biotite from Čierna hora Mountains granitoids (Western Carpathians, Slovakia) and estimation of water contents in granitoid melts

Bónová¹,

Broska²,

Petrík³

2010

Geologica Carpathica

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“…[32,33] Halogen fugacity can be computed using equations of Munoz,which are based on the revised coefficients for the halogen-hydroxyl exchange. [33,34] These equations are as follows: Figure 5: Plot of (a) variations of Fe 3+ -Fe 2+ -Mg in biotite collected from the Lar prospect igneous rocks; diagram after Wones and Eugster; [38] Fe 3+ calculated according to Dymek, [10] (b) Log f(O 2 ) -T for the biotite stability as a function of Fe/(Fe+Mg) ratio at total pressure of 2070 bars. [31] Curve labelled 0 represents maximum phlogopite stability and area bounded by curve labelled 100 is the annite stability field.…”

Section: Resultsmentioning

confidence: 99%

Untitled

Moradi¹

2017

IJGP

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Background and Objective: The Lar Cu-Mo prospect is located in Sistan suture zone, southeast of Iran. In this study, the chemical composition of biotite is determined using electron probe micro-analyzer in shoshonitic igneous rocks. Shoshonitic rocks are syenitic to monzonitic in composition that can be divided into the granular and porphyroid groups. Methods: Studying biotites generally occurs as primary and secondary types. The primary biotites are large poikilitic phenocrysts associated with Fe-Ti oxides, giving the rocks a spotted texture. In addition, secondary biotites show varying size, color, and shape. All of the Lar analyzed biotites are Mg-and Ti-rich and F-and Cl-poor. Analyses of the Lar biotites suggested that crystallization took place at an average temperature of 731°C and 640°C for primary and secondary samples, respectively. Results: Estimation of the oxygen fugacity, based on chemical composition and Fe3+ content of biotite, shows that the oxygen fugacity was limited in fayalitemagnetite quartz to middle of HM buffers in quality and was about 10 −12 to 10 −14 bar in quantity for primary and secondary type, respectively. Halogen fugacity ratios in biotite show that the Lar porphyroid rocks (ore-bearing) are affected mainly by meteoric water than granular type (barren). Calculated halogen fugacity values for biotite in the Lar Cu-Mo prospect are consistent with many other porphyry copper-forming systems. Conclusion: The Lar Cu-Mo prospect was formed by the hydrothermal activity related to the syenitic to monzonitic porphyroid igneous rocks with shoshonitic nature which introduces the Lar igneous complex volcanic sequence. The hydrothermal alterations are limited and occurred as silicic, potassic, phyllic, propylitic, and argillic. Hypogene sulfide minerals mainly occur as disseminated and sulfidic and silicic veins and veinlets consisting of chalcopyrite, bornite, molybdenite, and minor pyrite. Biotite as main ferromagnesian mineral of host rocks occurs as primary in less altered rocks and secondary in the alteration areas.

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“…In all analyzed samples, biotite is fresh with minimal alteration effects ( Figure 7a; Nachit et al, 2005). According to the revised mica classification (Rieder et al, 1999), all of the studied biotites plot in the biotite field, and its compositions in the granite and some monzodiorite rocks, show a slight tendency toward iron enrichment ( Figure 7b).…”

Section: Biotitementioning

confidence: 99%

Nature and physicochemical conditions of crystallization in the South Dehgolan intrusion, NW Iran: mineral-chemical evidence

Sarjoughian¹,

Kananian²,

Lentz³

et al. 2015

Turkish J Earth Sci

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The South Dehgolan intrusion in the Sanandaj-Sirjan Zone ranges in composition from calc-alkalic monzogabbro to syenite to alkalic granite. This suite is composed mainly of variable proportions of quartz, K-feldspar, plagioclase, biotite, hornblende, and pyroxene. The plagioclase composition varies between albite to labradorite. The biotites are Mg-to Fe-rich in the monzogabbro to granite, respectively. The amphiboles are calcic and the composition varies from magnesiohornblende to actinolite. Clinopyroxene compositions fall in the diopside-augite field. The average calculated near-solidus crystallization temperatures are 774 °C, 655 °C, and 775 °C for the monzogabbro-monzodiorite, syenite, and granite, respectively. Calculated average pressures of emplacement are 1.7, 1.3, and 1.9 kbar for the monzogabbro-monzodiorite, syenite, and granite rocks, respectively, crystallizing at different respective depths of about 6.7, 5.0, and 7.3 km. The interpreted oxygen fugacities in the monzogabbro-monzodiorite and syenite rocks are typical of arc magmas, with oxygen fugacities above the Ni-NiO buffer. Water contents in the monzogabbro-monzodiorite and syenite were calculated to range from 4.7 to 4.4 wt.% and in the granite is 3.8 wt.%. High water and volatile contents in the monzogabbro to syenite may have allowed the magma to reach shallower crustal levels. During the evolution of this magmatic system to higher silica contents, there was an increase in the activity of oxygen and decrease in the temperature and the emplacement depth from the monzogabbro-monzodiorite to syenite rocks; this is consistent with the typical evolution of the granitoid rocks. However, the calculated higher temperature and pressure and low ƒO 2 and H 2 O content in the later granite reflects notable differences in its origin and crystallization conditions. The range in mineral compositions is this intrusive suite is consistent with a relationship to subduction of the Neotethys oceanic crust beneath the Central Iranian microcontinent, although there was a change from calc-alkaline to alkaline magmatism.

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Discrimination between primary magmatic biotites, reequilibrated biotites and neoformed biotites

Cited by 360 publications

References 4 publications

Biotite from Čierna hora Mountains granitoids (Western Carpathians, Slovakia) and estimation of water contents in granitoid melts

Biotite from Čierna hora Mountains granitoids (Western Carpathians, Slovakia) and estimation of water contents in granitoid melts

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Nature and physicochemical conditions of crystallization in the South Dehgolan intrusion, NW Iran: mineral-chemical evidence

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