Petrogenetic Aspects of Acid and Basaltic Lavas from the Paran  Plateau (Brazil): Geological, Mineralogical and Petrochemical Relationships

Bellieni, G.; Comin-Chiaramontí, P.; Marques, Leila Soares; Melfi, Adolpho José; Nardy, Antônio José Ranalli; Papatrechas, Ch.; Piccirillo, E. M.; Roisenberg, Arí; Stolfa, D.

doi:10.1093/petrology/27.4.915

Cited by 209 publications

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“…1). The spatial distribution of the tholeiitic -ATP and transitional-tholeiitic-ATC suites indicates that acidic volcanic rocks may have been derived from the associated basalts, or ATC melts are derived from tholeiitictransitional basalts and ATP from tholeiitic basalts as suggested by Bellieni et al (1986) and Garland et al (1995). …”

Section: Petrographic and Geochemical Aspects Of Silicic Volcanic Rocksmentioning

confidence: 80%

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New insights on the occurrence of peperites and sedimentary deposits within the silicic volcanic sequences of the Paraná Magmatic Province, Brazil

Luchetti¹,

Nardy²,

Machado³

et al. 2014

Solid Earth

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Abstract. The PMP (Paraná Magmatic Province) is characterized by lava flows of the Early Cretaceous Serra Geral Formation which covers about 75 % of the Paraná Basin (southern and southeastern Brazil), composed of a thick (up to 1600 m) volcanic sequence formed by a succession of petrographically and geochemically distinct units of basic and silicic composition. The whole package must have been emplaced during approximately 3 million years of nearly uninterrupted activity. A few aeolian sandstone layers, indicating arid environmental conditions (the Botucatu Formation), are interlayered in the lower basalts. Above the basalts, the Palmas and Chapecó Members are composed of silicic volcanic rocks (quartz latites, dacites, rhyodacites and rhyolites) and basalts. This paper presents new evidence of sedimentation episodes separating silicic volcanic events, expressed by the occurrence of sedimentary deposits. Interaction between the volcanic bodies and the coeval unconsolidated sediments formed peperites. The sediments were observed between basaltic lava flows and silicic rocks or interlayered in the Palmas-type rocks, between the Chapecó-type rocks and overlying basaltic flows, between silicic bodies of the Palmas and Chapecó types, and interlayered within Palmas-type units. The observed structures indicate that the sediments were still wet and unconsolidated, or weakly consolidated, at the time of volcanism, which, coupled with the sediment features, reflect environmental conditions that are different from those characterizing the Botucatu arid conditions.

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Section: Petrographic and Geochemical Aspects Of Silicic Volcanic Rocksmentioning

confidence: 80%

“…The 1600 m thick PMP volcanic sequence consists of up to 32 lava flows of predominantly basic to intermediate compositions (tholeiitic basalts, andesi-basalts and andesites), as well as felsic volcanic rocks (dacites, rhyodacites and rhyolites; Bellieni et al, 1984Bellieni et al, , 1986.…”

Section: Stratigraphymentioning

confidence: 99%

New insights on the occurrence of peperites and sedimentary deposits within the silicic volcanic sequences of the Paraná Magmatic Province, Brazil

Luchetti¹,

Nardy²,

Machado³

et al. 2014

Solid Earth

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“…Posteriormente, estas rochas efusivas foram classificadas como (Gordon Jr. et al 1947), na qual predominam derrames basálticos toleíticos (90% do volume total), com andesitos toleíticos (7%) e dacitos, riodacitos e riolitos subordinados (Bellieni et al 1986). Destes, 2,5% compreendem rochas afíricas (Tipo Palmas) e 0,5%, rochas porfiríticas (Tipo Chapecó), totalizando 64.000km² (Bellieni et al 1986, Nardy et al 2002. Enxames de diques e soleiras de microgabro permeiam os estratos vulcânicos e sedimentares da bacia.…”

Section: Large Igneous Province Eruptivas Da Serra Geralunclassified

“…(Bellieni et al, 1986;Piccirillo et al, 1987, Figura 1). A Subprovíncia Sul caracteriza-se pela sobreposição de corpos ácidos do Tipo Palmas aos derrames básicos e distingue-se também em função do baixo teor de TiO (<2%) e empobrecimento em P, Sr, Ba, La, Ce, Zr e Y em suas rochas .…”

Section: Large Igneous Province Eruptivas Da Serra Geralunclassified

“…Contudo, a LIP do Paraná parece carecer de rochas desta natureza. Comin-Chiaramonti et al (1988), Bellieni et al (1986), Henry e Wolff (1992), Umann et al (2001), Lima et al (2012), Waichel et al (2012), Chmyz (2013, entre outros, realizaram estudos em diferentes áreas da Província Magmática Paraná-Etendeka (PMPE) e consideraram as rochas ácidas como sendo ou resultantes da . Portanto, atribuem uma origem lávica ( ) às rochas ácidas.…”

Section: Discussões E Consideraçõesunclassified

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Platô de São Joaquim, Província Magmática do Paraná: Feições de Campo e Questões Genéticas

Besser

Vasconcellos

Nardy

2015

GEO

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ResumoO Platô de São Joaquim (PSJ) situa-se no Planalto Sul de Santa Catarina, no extremo sudeste do Planalto Meridional do Brasil. O platô sobrepõe-se aos basaltos da Formação Serra Geral, os quais são dispostos principalmente na forma de derrames pahoehoe, mas também de derrames a'a'. As rochas félsicas do Platô de São Joaquim configuram extensos derrames de geometria tabular e espessura de até 100 m que se distribuem por 280 km². Morros testemunhos nas circunvizinhanças conservam porções remanescentes destes derrames, evidência de que sua extensão fora muito maior e que agora se encontra reduzida pela erosão. A estratigrafia da sequência sobreposta aos basaltos comumente arquiteta-se da seguinte forma: (1) nível decamétrico de rochas de caráter transicional, representadas por vulcanitos afaníticos de cor cinza-avermelhada ou vermelha, maciços a amigdaloides podendo conter geodos decimétricos; (2) nível métrico saprolítico amigdaloide de cor amarela e geometria ondulada, com amígdalas estiradas e atualmente preenchidas por argilas brancas, brechas autoclásticas formadas por púmice/escória intemperizados e lentes de pitchstone; (3) nível basal félsico decamétrico formado por lentes de pitchstone e rochas afaníticas com bandamento de fluxo laminar plano-paralelo, contorcido ou dobrado; (4) nível félsico decamétrico com disjunções em lajes; (5) nível félsico de espessura decamétrica (até 65 m) formado por rochas faneríticas finas maciças, com ou sem disjunções tabulares; (6) na porção superior do nível maciço observam-se raras amígdalas. Devido à falta de evidências que atribuam uma gênese ignimbrítica a estas rochas, tais vulcanitos do platô de São Joaquim são preliminarmente designados como Riolitos de Platô da Formação Serra Geral.Palavras-chave: Província do Paraná; Platô de São Joaquim; estratigrafia de sequências vulcânicas; riolitos de platô. Abstract The São Joaquim Plateau (SJP) is located in the Southern

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Petrology and geochemistry of the ultramafic-mafic Mawpyut complex, Meghalaya: a Sylhet trap differentiation centre in northeastern India

et al. 2013

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The present article describes, for the first time, petrological and geochemical details of the Mawpyut differentiated complex which is related to the Sylhet trap located at Jaintia Hills district, Meghalaya, northeastern India. The Mawpyut complex occurs as an arcuate body that intrudes into the surrounding Shillong Group rocks. The complex in general contains ‘ultramafic’ and ‘mafic’ rocks, as well as minor syenitic veins that postdate the main units. The lithotypes correspond to cumulate and noncumulate units. The cumulate unit is represented by olivine clinopyroxenite, clinopyroxenite, plagioclase‐bearing ultramafic, olivine gabbronorite, mela‐gabbronorite, melagabbro, orthopyroxene gabbro, and gabbro, all with a pronounced cumulus texture. The noncumulate unit is marked by gabbro, monzonite, monzodiorite, and quartzsyenite. The use of several major and trace element variation diagrams suggests that magmatic differentiation led to the formation of cumulate and noncumulate units. In chondrite‐normalized REE diagrams the cumulate rocks show flat LREE and MREE patterns and a moderate positive Eu anomaly (in plagioclase‐bearing ultramafics) due to plagioclase cumulation. The rocks of the noncumulate unit show a strongly fractionated REE pattern and no Eu anomaly. The noncumulate mafic rocks are geochemically comparable to high‐phosphorous/high‐titanium basalts (HPT) indicative of low pressure fractional crystallization. In a primitive mantle‐normalized multielement diagram some of the cumulate rocks show pronounced negative anomalies for K and P, indicating anorogenic mafic magmatism in a within‐plate setting. The rocks of the noncumulate unit show a slight negative anomaly for Yb and a Nb–Ta trough, indicating a subduction‐related signature that perhaps is inherited from subducted sedimentary rocks incorporated during crustal contamination of the derived magma (left after crystal cumulation) with country rocks. Various trace element ratios for the cumulate mafic rocks indicate parent EMI/EMII/HIMU sources with a very limited crustal signature. The noncumulate mafic rocks (corresponding to the derived evolved magma) indicate EMI/EMII/HIMU sources with a pronounced crustal contamination. The Sr–Nd isotopic compositions of the Mawpyut samples typically plot in the continental flood basalt field, with an affinity to the EMII source. The isotopic compositions of the noncumulate rocks also clearly indicate crustal contamination. We suggest that partial melting (involving garnet in the residue) of the enriched mantle source EMI/EMII/HIMU could have derived the parental melt; this melt, in turn, underwent assimilation and fractional crystallization to produce the variety of cumulate‐noncumulate lithologies of the Mawpyut complex. Copyright © 2013 John Wiley & Sons, Ltd.

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Petrogenetic Aspects of Acid and Basaltic Lavas from the Paran Plateau (Brazil): Geological, Mineralogical and Petrochemical Relationships

Cited by 209 publications

References 0 publications

New insights on the occurrence of peperites and sedimentary deposits within the silicic volcanic sequences of the Paraná Magmatic Province, Brazil

New insights on the occurrence of peperites and sedimentary deposits within the silicic volcanic sequences of the Paraná Magmatic Province, Brazil

Platô de São Joaquim, Província Magmática do Paraná: Feições de Campo e Questões Genéticas

Petrology and geochemistry of the ultramafic-mafic Mawpyut complex, Meghalaya: a Sylhet trap differentiation centre in northeastern India

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