On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil

Naranjo, Salazar; Vlach, Sílvio Roberto Farias

doi:10.1590/2317-4889201820180033

Cited by 8 publications

(8 citation statements)

References 66 publications

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“…Qualitative redox conditions estimates and correlation with the magnetite and ilmenite series from Ishihara (1977) according to Anderson and Smith (1995) and Anderson et al (2008), respectively. (Munoz, 1992), assuming biotite-fluid equilibrium at 750°C for primary annite and at 350°C for secondary annite-siderophyllite (see also Salazar-Naranjo and Vlach, 2018). Symbols as in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…14c (e.g. Salazar-Naranjo and Vlach, 2018). Annite crystals in the alkaline-1 series present relatively constant log( f HF /f HCl ) = -2 values, whereas annite and siderophyllite types in the aluminous and the alkaline-2 series present values with a large dispersion, between -2.5 and -1.1 and -3.8 and -2.3, respectively.…”

Section: Volatile (H 2 O F and Cl) Fugacity Relationsmentioning

confidence: 99%

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Amphiboles and phyllosilicates in the A-type Mandira Granite Massif, Graciosa Province, SE Brazil: Textures, composition and crystallisation conditions

Siachoque

Santos

Vlach

2021

MinMag

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Amphibole and biotite were the principal mafic minerals precipitated during the magmatic and post-magmatic (including hydrothermal) crystallisation stages of coeval metaluminous to slightly peraluminous syenogranites and peralkaline alkali-feldspar granites of the Mandira Granite Massif, in the post-collisional A-type Graciosa Province, S-SE Brazil. Magmatic calcic (ferro-ferri-hornblende and hastingsite) amphiboles occur in the metaluminous syenogranites, whereas calcic (ferro-edenite), sodic–calcic (ferro-ferri-winchite) and sodic (arfvedsonite and riebeckite) amphiboles occur in peralkaline alkali-feldspar granites. Rare earth element (REE) contents decrease from hornblende to winchite and riebeckite, and the partition coefficients indicate increasing compatibility from light rare earth elements (LREE) to heavy rare earth elements (HREE), with a marked preference for the HREE over the LREE in the sodic–calcic and, particularly, the sodic amphiboles. Post-magmatic calcic- (ferro-actinolite) and sodic- (riebeckite) amphiboles are also present in the peralkaline granites. Magmatic biotite (annite) is dominant in syenogranites, whereas post-magmatic annite and late-to post-magmatic annite evolving to siderophyllite occurs in the peralkaline granites. Typical hydrothermal phyllosilicates are chlorite (chamosite) in syenogranites and related greisens, and ferri-stilpnomelane which is present in both peralkaline granites and metaluminous syenogranites. Lithostatic pressure estimates suggest that the main granites were emplaced under pressures of ~93–230 MPa, with close-to-liquidus temperatures varying from ~830°C for syenogranites to ~900°C for the peralkaline granites. The original magmas crystallised mainly under relatively reduced (buffered at ~ –1 ≤ QFM ≤ 0), and more oxidising (somewhat above QFM) environments, respectively. Chlorite, replacing biotite in syenogranites and as the main mineral in the related greisens, permits the temperature of the main hydrothermal event to have taken place between 250 and 272°C. Estimated log (fHF/fHCl) values from biotite compositions vary from ~ –2 to –1 (syenogranites) and ~ –3.5 to –2 (peralkaline granites) and indicate F preference over Cl in the hydrothermal fluid phase.

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Section: Discussionmentioning

confidence: 99%

Section: Volatile (H 2 O F and Cl) Fugacity Relationsmentioning

confidence: 99%

Amphiboles and phyllosilicates in the A-type Mandira Granite Massif, Graciosa Province, SE Brazil: Textures, composition and crystallisation conditions

Siachoque

Santos

Vlach

2021

MinMag

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“…6). Apatite is an early phase relative to zircon in the crystallization sequence from both plutons, and apatite exhibits significantly higher saturation temperatures (e.g., Anderson et al 2008, Naranjo andVlach 2018) with an acceptable near-liquidus to solidus temperature span of ~940 to ~700°C.…”

Section: Intensive Crystallization Parametersmentioning

confidence: 99%

Rapid magma ascent and formation of the Águas Belas-Canindé granitic batholith, NE Brazil: evidence of epidote dissolution and thermobarometry

et al. 2020

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Mineral chemistry and intensive parameter estimates for the Major Isidoro (626 Ma) and Monteirópolis (627 Ma) magmatic epidote-bearing granitic plutons, emplaced along the Jacaré dos Homens transpressional shear zone (JHSZ), Borborema Province, are focused in this study. These plutons consist of medium-to-coarse grained equigranular to porphyritic tonalite to granite that show abundant dioritic enclaves. These granites contain biotite (Fe# 0.44 to 0.55), Fe-edenite (Major Isidoro), hastingsite (Monteirópolis), titanite, and epidote that often show allanite core as key mafic mineral phases. Pistacite molecular content in epidote is in the interval of 27 to 31 mol%, presenting TiO 2 < 0.30%, typical for magmatic epidote. Estimated intensive parameters reveal crystallization at 6.5 ± 1 (Major Isidoro) and 4.7 ± 0.6 kbar (Monteirópolis), temperatures from ~940°C (near-liquidus) to 675 ± 35°C (near-solidus) and oxidizing conditions. Partial corrosion of epidote took place during 15.6 to 32 (Major Isidoro) and 27-49 years (Monteirópolis), corresponding to rather high magma ascension rates of 365 to 750 and 395 to 635 m.years-1 , respectively. The JHSZ likely favored upward magma transport at the Sergipano and Pernambuco-Alagoas domains boundary, during the onset of the Brasiliano orogeny (650-620 Ma).

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“…log(XF/XCL) diagram coupled to the fugacity halogen log (fHF/fHCl) ratios represented by the dashed lines as show in Figure 2-11C (e.g. Salazar-Naranjo and Vlach, 2018). In this diagram, we separated the different calculated log (fHF/fHCl) ratios at fixed 750°C (magmatic) and 350°C…”

Section: Volatile Fugacitiesmentioning

confidence: 99%

“…In contrast, annites in the peralkaline granites from the alkaline-2 association plot over the log (fHF/fHCl) = -2, suggest an equal biotite-fluid equilibration. Munoz (1992), assuming biotite-fluid equilibrium at 750°C for primary annites and at 350°C for late-to post-magmatic annite-siderophyllite types (after Salazar-Naranjo and Vlach, 2018). Symbols as in Figure 2-6.…”

Section: Volatile Fugacitiesmentioning

confidence: 99%

Main mafic and accessory mineralogy in granites and greisens from selected occurrences in the A-type Graciosa Province, S-SE Brazil, and petrological implications

Velandia¹

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On the crystallization conditions of the Neoproterozoic, high-K calc-alkaline, Bragança Paulista-type magmatism, southern Brasília Orogen, SE Brazil

Cited by 8 publications

References 66 publications

Amphiboles and phyllosilicates in the A-type Mandira Granite Massif, Graciosa Province, SE Brazil: Textures, composition and crystallisation conditions

Amphiboles and phyllosilicates in the A-type Mandira Granite Massif, Graciosa Province, SE Brazil: Textures, composition and crystallisation conditions

Rapid magma ascent and formation of the Águas Belas-Canindé granitic batholith, NE Brazil: evidence of epidote dissolution and thermobarometry

Main mafic and accessory mineralogy in granites and greisens from selected occurrences in the A-type Graciosa Province, S-SE Brazil, and petrological implications

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