The onset of flood basalt volcanism, Northern Paraná Basin, Brazil: A precise U–Pb baddeleyite/zircon age for a Chapecó-type dacite

Janasi, Valdecir de Assis; Freitas, Vivian Azor de; Heaman, L. M.

doi:10.1016/j.epsl.2010.12.005

Cited by 213 publications

(79 citation statements)

References 33 publications

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“…Mincato et al, 2003;Thiede and Vasconcelos, 2010;Pinto et al, 2010). More recently, Janasi et al (2011), using U / Pb ratios from baddeleyite/zircon crystals determined by isotope dilution thermal ionization mass spectrometry from rocks of the Chapecó Member, obtained an age of 134.3 ± 0.8 Ma, compatible with previous age determinations. However, ages obtained in the basaltic flows indicate the duration of the volcanism to be around 3 Ma, which is consistent with paleomagnetic data presented by Ernesto and Marques (2004).…”

Section: Introductionsupporting

confidence: 77%

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: Introductionsupporting

confidence: 77%

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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“…Most recently, Thiede and Vasconcelos (2010) placed PCFB extrusion at 134.6 ± 0.6 Ma, concluding that the duration of the PCFB volcanism was less than 1.2 Ma. Baddeleyite/zircon LA-ICP-MS (laser ablation-inductively coupled plasma-mass spectrometry) and U-Pb age dating on felsic volcanic rocks from the PCFB yielded an age of 134.3 ± 0.8 Ma (Janasi et al, 2011), confirming the idea that this magmatic event was emplaced over a short period of about 1-2 Ma.…”

Section: Geological Settingmentioning

confidence: 63%

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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“…This formation belongs to the Paraná Magmatic Province, which spreads across approximately 917,000 km 2 (± 15,000 Km 2 ), with a volume of more than 600,000 km 3 (450,000 km 3 extrusive, and 112,000 km 3 intrusive sill-type bodies; Frank et al 2009) in central to south Brazil and neighboring areas in Argentina, Paraguay, and Uruguay, constituting one of the largest provinces of continental basalts in the world (Jerram & Widdowson 2005). The basalt volcanism preceded the opening of the South Atlantic, and recent precise Ar-Ar dating indicates that the main phase of volcanic activity occurred between 134 and 131 Ma (e.g., Thiede & Vasconcelos 2010, Janasi et al 2011. Tholeiitic basalts are largely predominant in the province, and a major two-fold division based on the TiO 2 content or Ti/Y ratio is recognized, with the low Ti/Y sequence restricted to the southernmost portion (e.g., Bellieni et al 1984, Peate 1997.…”

Section: Geological Contextmentioning

confidence: 99%

Local geological sections and regional stratigraphy based on physical geology and chemical stratigraphy of the Serra Geral Group from Araraquara to Avaré, SP

et al. 2018

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The onset of flood basalt volcanism, Northern Paraná Basin, Brazil: A precise U–Pb baddeleyite/zircon age for a Chapecó-type dacite

Cited by 213 publications

References 33 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

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

Local geological sections and regional stratigraphy based on physical geology and chemical stratigraphy of the Serra Geral Group from Araraquara to Avaré, SP

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