Re–Os isotope and highly siderophile element systematics of the Paraná continental flood basalts (Brazil)

Rocha-Júnior, Eduardo R.V.; Puchtel, I. S.; Marques, Leila Soares; Walker, Richard J.; Machado, Fábío Braz; Nardy, Antônio José Ranalli; Babinski, Marly; Figueiredo, Ana Maria Graciano

doi:10.1016/j.epsl.2012.04.050

Cited by 79 publications

(35 citation statements)

References 68 publications

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“…10). The results provide evidence that the majority of the NW-PCFB tholeiites have high-TiO 2 contents (2.6-4.2 wt %), as do most of the basalts from the northern PCFB reported in previous studies (e.g., Piccirillo and Melfi, 1988;Peate et al, 1992;Marques et al, 1999;Rocha-Júnior et al, 2012, 2013. Of this high-Ti group, we can distinguish two magma types which emerge from the major, minor, and trace element compositions, referred to as Pitanga (predominant) and Paranapanema (subordinate) magma types, according to the parameters proposed by Peate et al (1992).…”

Section: Major Minor and Trace Element Geochemistrysupporting

confidence: 58%

Volcanological aspects of the northwest region of Paraná continental flood basalts (Brazil)

Machado

Rocha-Júnior

Marques³

et al. 2015

Solid Earth

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Abstract. There has been little research on volcanological aspects of Paraná continental flood basalts (PCFBs), and all investigations have mainly been concentrated on the internal portions of the lava flows. Thus, this study describes for the first time morphological aspects of lava flows and structural characteristics caused by lava-sediment interaction in the northwestern PCFB province (NW-PCFB). Early Cretaceous (134 to 132 Ma) tholeiitic rocks of the PCFB were emplaced on a large intracratonic Paleozoic sedimentary basin (Paraná Basin), mainly covering dry eolian sandstones (Botucatu Formation). As this sedimentary unit is overlain by the basic lava flows of the PCFB, the interaction of lavas and unconsolidated sediments resulted in the generation of fluidal peperites. This aspect is significant because it shows that restricted wet environments should have existed in the Botucatu desert. The peperite zones of the NW-PCFB are associated with compound pahoehoe-type (P-type) flows and are always related to the first volcanic pulses. These flows have dispersed vesicles and sand-filled cracks in their base and top borders, as well as the presence of interlayered sandstones with irregular contacts and varied thicknesses. It is remarkable that, to the best of current knowledge, only in this area of the whole PCFB did the volcanic activity start with lowTi basalt flows of Ribeira type (TiO 2 < 2.3 wt %), which are scarce in the province.

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Section: Major Minor and Trace Element Geochemistrysupporting

confidence: 58%

Volcanological aspects of the northwest region of Paraná continental flood basalts (Brazil)

Machado

Rocha-Júnior

Marques³

et al. 2015

Solid Earth

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“…However, the origin and evolution of such provinces remain a disputed subject, with no agreement about the role of shallow/deep mantle plumes as the triggers of the magmatic activity, as well as the participation of subcontinental lithospheric mantle (SCLM) and subduction-related materials (ancient oceanic crust and sediments) in their genesis (e.g., White & McKenzie 1989;Richards et al 1989;Anderson 1994;De Min et al 2003;Rocha-Júnior et al 2012, 2013Heinonen et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Lead isotope constraints on the mantle sources involved in the genesis of Mesozoic high-Ti tholeiite dykes (Urubici type) from the São Francisco Craton (Southern Espinhaço, Brazil)

et al. 2016

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ABSTRACT:The first results of Pb isotope compositions of the high-Ti Mesozoic dykes of the Southern Espinhaço are presented. The results do not show large variations and are significantly more radiogenic than the Pb isotope compositions of the high-Ti tholeiites from the Paraná Continental Flood Basalts. The data combined with published geochemical and Sr-Nd isotope results rule out crustal contamination processes in the genesis of the dykes, requiring magma generation in metasomatized subcontinental lithospheric mantle with the involvement of HIMU-type and carbonatite components. The magmas may have been also derived from a mantle source containing ~4 -5% of pyroxenite and ~1% of carbonatite melts, agreeing with published Os isotope compositions of high-Ti rocks from the Paraná Continental Flood Basalts. These metasomatizing agents could be responsible for mantle source refertilization, as was also proposed in the literature to explain the characteristics of xenoliths of the Goiás Alkaline Province, which also occurs in the border of the São Francisco Craton. Additionally, to evaluate the risks of Pb contamination during sample preparation for analysis, several experimental tests were accomplished, which indicate the need of sawed surface removal and a careful washing of small-sized rock fragments before powdering, especially for rocks with [Pb] < 7 μg/g.

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“…Em trabalhos recentes, Rocha-Júnior et al (2012 Ar sugerem que o magmatismo Serra Geral teve duração < 1,2 milhão de anos e foi iniciado há 134,7 ± 1 Ma, o que resultou em uma taxa de erupção mínima geral de ~2,0 km³ de magma por ano (Renne et al, 1996 e referências ali contidas; Thiede & Vasconcelos, 2010 Brasiliano e a evolução dessa subsidência à flexura litosférica regional por sobrecarga tectônica, ambas devido a uma série de episódios orogênicos ocorridos na borda sul-ocidental do paleocontinente Gondwana -os Gondwanides -uma extensa faixa de orógenos fanerozóicos e bacias associadas.…”

Section: Bacia Do Paranáunclassified

“…O fator reforça ainda mais a hipótese da diferença entre dois reservatórios mantélicos sob a Bacia do Paraná. O limite litosfera-astenosfera sob a porção norte da Bacia do Paraná teria sido enriquecido ainda durante o Neoproterozóico (Rocha-Júnior et al, 2012Padilha et al, 2015). Este cenário poderia explicar a diferença geoquímica observada entre os basaltos da porção norte da Bacia do Paraná, ricos em TiO2, e os da porção sul, pobres em TiO2 (Bellieni et al, 1984).…”

Section: Considerações Sobre a Evolução Da Bacia Do Paraná E Da Margeunclassified

Modelo de velocidade sísmica de ondas P da crosta e manto superior ao longo do perfil PABBRISE, estado de São Paulo

Bernardes¹

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Re–Os isotope and highly siderophile element systematics of the Paraná continental flood basalts (Brazil)

Cited by 79 publications

References 68 publications

Volcanological aspects of the northwest region of Paraná continental flood basalts (Brazil)

Volcanological aspects of the northwest region of Paraná continental flood basalts (Brazil)

Lead isotope constraints on the mantle sources involved in the genesis of Mesozoic high-Ti tholeiite dykes (Urubici type) from the São Francisco Craton (Southern Espinhaço, Brazil)

Modelo de velocidade sísmica de ondas P da crosta e manto superior ao longo do perfil PABBRISE, estado de São Paulo

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