Bulk rock and mineral chemistries and ascent rates of high-K calc-alkalic epidote-bearing magmas, Northeastern Brazil

Brasilino, Roberta Galba; Sial, Alcídes N.; Ferreira, Valderez P.; Pimentel, Márcio Martins

doi:10.1016/j.lithos.2011.09.017

Cited by 19 publications

(10 citation statements)

References 54 publications

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“…Thus, a combination of the inclusion and matrix phases probably suggests that crystallization of the magmatic epidote has started at a relatively early stage of solidification and continued until near-solidus stage. Brasilino et al (2011), studying magmatic epidote-bearing calc-alkalic granodiorites to monzogranites from northeastern Brazil, concluded that oxidation of host magma stabilized and preserved magmatic epidote. The systematic increase of oxidation state of the host magma during crystallization, which is revealed by systematic increase of X Fe in epidote from inclusion to matrix crystals, probably stabilized the magmatic epidote in the matrix of the Hazu tonalites.…”

Section: Discussionmentioning

confidence: 99%

Magmatic zoisite and epidote in tonalite of the Ryoke belt, central Japan

Masumoto

Enami

Tsuboi

et al. 2014

ejm

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Magmatic epidote and zoisite commonly occur in Cretaceous tonalite of the Hazu area in the Ryoke belt, central Japan. The tonalite is mainly composed of amphibole, biotite, plagioclase, quartz, and epidote/zoisite with minor ilmenite, magnetite, pyrite, zircon, and apatite. Small amounts of K-feldspar occur as an interstitial phase between other felsic phases or perthitic patches in plagioclase. Epidote occurs as inclusions in plagioclase, as interstitial phase in the matrix, and as secondary phase in chlorite pseudomorphs after biotite, and in saussuritized plagioclase. The X Fe [¼ Fe 3þ /(Al þ Fe 3þ)] value of the secondary epidote ranges from 0.27 to 0.39. Epidote inclusions in plagioclase and interstitial grains contain less Fe 3þ (X Fe ¼ 0.08-0.29), Fe 3þ-poor epidote with X Fe , 0.18 occurs only as inclusion. Zoisite with X Fe value of 0.01-0.07 occurs only as inclusions in plagioclase, and usually has thin lamella-like layers of Fe 3þ-poor epidote with X Fe ¼ 0.09-0.14. The Fe 3þ-poor epidote with X Fe , 0.20 and zoisite included in plagioclase occasionally form aggregates with K-feldspar and quartz. A thin sodic plagioclase zone develops at the boundary between the Fe 3þ-poor epidote and zoisite inclusions and their host plagioclase. Such a reaction texture is not observed at the boundary between Fe 3þ-richer epidote inclusions with X Fe. 0.20 and their host plagioclase. Epidote grains with X Fe. 0.20 in plagioclase and the matrix are a magmatic phase that crystallized directly from the tonalite magma. The Fe 3þ-poor epidote (X Fe , 0.20) and zoisite were probably formed by a local reaction between the trapped melt and its host plagioclase, and these are considered not to have been in equilibrium with the tonalite magma. Compositions of amphibole-plagioclase assemblages allowed for temperature estimates in the range of 730-770 C and minimum pressures of 0.47-0.57 GPa for the epidote/zoisite-bearing tonalites of the Hazu area. Epidote/ zoisite-free tonalites occur in other areas of the Ryoke belt. There may be several tonalite bodies that record different intrusion processes and solidification depths in the Ryoke belt.

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Section: Discussionmentioning

confidence: 99%

Magmatic zoisite and epidote in tonalite of the Ryoke belt, central Japan

Masumoto

Enami

Tsuboi

et al. 2014

ejm

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“…Epidote dissolution in residual melts is explained by non-equilibrium conditions when relatively high-pressure epidote is brought up from deeper levels in the magma and mineral aggregates shield and prevent re-equilibration of the epidote inclusions with residual melt (e.g., Brandon et al 1996). The textural relationships of epidote with other minerals in rocks yield compelling information on upward magma transport (e.g., Brandon et al 1996, 2008, Long et al 2005, Brasilino et al 2011. Sial et al (2008), based on dissolution kinetic experiments on epidote from Brandon et al (1996) and estimating the size of Figure 10.…”

Section: Granitic Magma Transport Estimatesmentioning

confidence: 99%

“…Thus, at fO 2 buffered by hematite-magnetite (HM) the stability of epidote is shifted to a lower pressure (> 0.3 GPa; Schmidt and Thompson 1996, Ferreira et al 2003, Schmidt and Poli 2004. Furthermore, this phase has been successfully employed to estimate the ascension rate of epidote-bearing magmas (e.g., Sial et al 1999, 2008, Brasilino et al 2011.…”

Section: Introductionmentioning

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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“…Quartz crystals can show mosaic texture, and epidote crystals occur associated with arfvedsonite, surrounding opaque minerals or shows allanite nuclei. Thus, allanite exhibits a texture typical of magmatic (primary) epidote ("type A" epidote, Sial et al 2008, Brasilino et al 2011.…”

Section: Geological Features and Petrographymentioning

confidence: 99%

Geochemistry of the Serra das Melancias Pluton in the Serra da Aldeia Suite: a classic post-collisional high Ba-Sr granite in The Riacho do Pontal Fold Belt, NE Brazil

et al. 2016

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ABSTRACT:The Serra da Aldeia Suite is composed by circular or oval-shaped plutons, intrusive in meta-sedimentary and meta-volcanosedimentary rocks in the Riacho do Pontal Fold Belt, NE Brazil. The Serra das Melancias Pluton, belonging to Serra da Aldeia Suite, is located southeastern of Piaui state, near Paulistana city. These plutons represent a major magmatic expression in this area and contain important information about the late magmatic/collisional geologic evolution of the Brasiliano Orogeny. Based on petrographic and geochemical data, three facies were defined in the Serra das Melancias Pluton: granites, syenites and quartz monzonites. The rocks display high-K and alkaline to shoshonitic affinities, are metaluminous and show ferrous character. They are enriched in Light Rare Earth Elements and Large Ion Lithophile Elements, with negative anomalies in Nb, Ta and Ti. Their high Ba, Sr, K/Rb, low Rb, relatively low U, Th, Nb to very low Heavy Rare Earth Elements and Y resemble those of typical high Ba-Sr granitoids. The geochemical data suggest the emplacement of Serra das Melancias Pluton in a transitional, late to post-orogenic setting in the Riacho do Pontal Fold Belt during the late Brasiliano-Pan African Orogeny.KEYWORDS: alkaline granites; geochemistry; Riacho do Pontal Fold Belt; Borborema Province; high Ba-Sr granites. RESUMO: A suíte Serra da Aldeia é composta por plútons graníti-cos circulares ou ovalados, intrusivos em sequências metassedimentares e metavulcanossedimentares na Faixa Riacho do

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Bulk rock and mineral chemistries and ascent rates of high-K calc-alkalic epidote-bearing magmas, Northeastern Brazil

Cited by 19 publications

References 54 publications

Magmatic zoisite and epidote in tonalite of the Ryoke belt, central Japan

Magmatic zoisite and epidote in tonalite of the Ryoke belt, central Japan

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

Geochemistry of the Serra das Melancias Pluton in the Serra da Aldeia Suite: a classic post-collisional high Ba-Sr granite in The Riacho do Pontal Fold Belt, NE Brazil

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