Geochronological data from the Faxinal coal succession, southern Paraná Basin, Brazil: A preliminary approach combining radiometric U-Pb dating and palynostratigraphy

Guerra-Sommer, Margót; Cazzulo-Klepzig, Miriam; Menegat, Rualdo; Formoso, Milton Luiz Laquintinie; Basei, Miguel Ângelo Stipp; Barboza, Eduardo Guimarães; Simas, Margarete Wagner

doi:10.1016/j.jsames.2007.06.007

Cited by 58 publications

(18 citation statements)

References 11 publications

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“…Taking into account important characteristics identified in the uppermost Coal Seam S, such as the patterns of floristic changes across the coal accumulation phase and the important compressed flora (Glossopteris Flora) preserved in the tonstein level (Guerra-Sommer et al, 2006, 2008a, and recent data from Jasper et al (2009) recording the presence of charcoal in this tonstein, the aim of the present study was to estimate, in a study case, the persistence of paleoecological conditions over a geologically short time span and to evaluate the effect of ash-fall deposition on coalforming plants. According to Crowley et al (1994), the water in peat mire often increased after deposition of volcanic ash, and palynological analysis could contribute significantly to determining if volcanic ash-fall affected the peat-forming vegetation in the mires, which formed the coals (Williams, 1992).…”

Section: P R O V a Smentioning

confidence: 99%

Effect of volcanic ash-fall on a Permian peat-forming environment, on the basis of palynology, palynofacies and paleobotany (Faxinal Coalfield, Brazil)

Cazzulo-Klepzig¹,

Filho²,

Guerra-Sommer³

et al. 2009

Rev. bras. paleont.

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-The aim of this paper was to assess, in a study case, whether ash-fall deposition influenced the character of the peat-forming vegetation in some coal beds in the southernmost Paraná Basin in Brazil, taking into consideration that records of tonstein levels are common in some coal bearing-strata. An investigation was made of the uppermost Faxinal coal seam (Coal Seam S), which displays two adjacent coal beds interbedded with a tonstein level. On the basis of the botanical affinity between the miospores and the parent plants as well as the relative abundance of the different plant groups, each coal plant assemblage was determined. Furthermore, previous paleobotanical data obtained on the tonstein level that identified a compressed Glossopteris flora were incorporated in the study. Palynofacies analyses performed on both coal and tonstein levels demonstrated good results for the recognition of preserved organic matter and changes in paleoenvironmental conditions along the coal sequence. The effect of volcanic ash-fall deposition was reflected by changes in the character of the vegetation associated with coal layers below and above the tonstein. Palynofacies results corroborated palynological and paleobotanical interpretation and contributed to the establishment of the floral succession deposited over a short time interval, under the effect of volcanic ash-fall deposition.Key words: palynology, paleobotany, palynofacies, coal, tonstein, Paraná Basin.RESUMO -O trabalho objetivou avaliar o efeito da deposição de cinza vulcânica sobre o caráter da vegetação responsável pela formação de alguns carvões na jazida do Faxinal, levando em consideração que registros de tonstein são comuns em sequências de carvão na porção sul da bacia do Paraná, no Brasil. Em estudo de caso, foi analisada a camada de carvão superior (Camada S) que apresenta, na sua porção mais superior, dois leitos adjacentes de carvão intercalados por um nível de tonstein originado de cinza vulcânica. A composição das palinofloras foi determinada com base na afinidade dos esporos e dos grãos de pólen e na relação de freqüência dos diferentes grupos vegetais. Dados paleobotânicos anteriores desenvolvidos nesse nível de tonstein, que demonstraram a presença de uma importante Flora Glossopteris, foram incorporados ao trabalho aqui proposto. As análises de palinofácies produziram resultados significativos para o reconhecimento da matéria

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Section: P R O V a Smentioning

confidence: 99%

Effect of volcanic ash-fall on a Permian peat-forming environment, on the basis of palynology, palynofacies and paleobotany (Faxinal Coalfield, Brazil)

Cazzulo-Klepzig¹,

Filho²,

Guerra-Sommer³

et al. 2009

Rev. bras. paleont.

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“…The present study focuses on a fossiliferous argillite approximately 7 cm thick, interbedded with the upper coal seam (S). Petrographic studies in this argillite reveal a volcanic ash-fall origin for this sediment, thus identifying it as a tonstein (Guerra-Sommer et al, 2008a). Ion microprobe (SHRIMP II) dating of zircons from the tonstein by Guerra-Sommer et al (2008b) yielded an age of 290.6 ± 1.5 Ma (Sakmarian).…”

Section: P R O V a Smentioning

confidence: 85%

Variation in stomatal numbers of Glossopteris leaves from the Lower Permian of Paraná Basin, Brazil

Schmidt¹,

Guerra-Sommer²,

Bernardes-de-Oliveira³

2011

Rev. bras. paleontol.

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-The stomatal density and index in compressed leaves of Glossopteris communis from two different roof shales from the Lower Permian in Paraná Basin, Brazil (Western Gondwana) have been investigated to test the possible relationship with modeled global changes in atmospheric CO 2 during the Phanerozoic. The obtained parameters show that the genus Glossopteris from the Cool Temperate biome can be used as CO 2 -proxy, despite the impossibility of being compared with living relatives or equivalents. When confronted with already published data for the Tropical Summer Wet biome, the present results confirm the detection of low levels of atmospheric CO 2 during the Early Permian, as predicted by the modeled curve. Nevertheless, the lower stomatal numbers detected at the climax of the coal interval (Faxinal Coalfield, Sakmarian) when compared to the higher ones obtained in leaves from a younger interval (Figueira Coalfield, Artinskian) could be attributed to temporarily high levels of atmospheric CO 2 . Therefore, the occurrence of an extensive peat generating event at the southern part of the basin and subsequent greenhouse gases emissions from this environment may have been enough to reverse regionally and temporarily the reduction trend in atmospheric CO 2 . Additionally, the Faxinal flora is preserved in a tonstein layer, which is a record of volcanic activity that could also cause a rise in atmospheric CO 2 . During the Artinskian, the scarce generation of peat mires, as revealed by the occurrence of thin and discontinuous coal layers, and the lack of volcanism evidence would be insufficient to affect the general low CO 2 trend.Key words: paleo-CO 2 proxy, pteridosperms, fossil cuticles, Rio Bonito Formation, peat-forming floras, Gondwana.RESUMO -Frequências estomáticas foram calculadas em cutículas de Glossopteris communis, procedentes de dois afloramentos do Permiano Inferior na bacia do Paraná, com o objetivo de relacioná-las com variações na concentração atmosférica de CO 2 modeladas para o Fanerozoico. Os resultados indicam que as glossopterídeas do bioma Temperado Frio podem ser utilizadas como equivalentes climáticos para inferência de níveis de CO 2 paleoatmosférico, apesar da impossibilidade de estabelecer um equivalente ecológico atual. Quando confrontados com dados obtidos para o bioma Tropical de Verão Úmido, os resultados aqui apresentados confirmam a detecção de baixos níveis de CO 2 na atmosfera durante o período, de acordo com o modelamento da curva. Porém, as frequências estomáticas mais baixas detectadas no clímax do intervalo formador de carvão (jazida de Faxinal, Sakmariano), quando comparadas às frequências mais altas obtidas nas folhas de intervalo mais jovem (jazida de Figueira, Artinskiano), poderiam ser atribuídas a níveis temporariamente altos de CO 2 na atmosfera. A ocorrência de extenso evento gerador de turfa na parte sul da bacia, com a consequente emissão de gases-estufa deste ambiente, poderia ter sido suficiente para reverter a tendência de queda de CO 2 atmosférico em âmbi...

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“…Several authors (Guerra-Sommer et al 1984, Dias and Guerra-Sommer 1994, Cazzulo-Klepzig et al 2007, Guerra-Sommer et al 2008b) performed palynological studies in the Faxinal Coalfield, which have demonstrated the dominance of gymnosperm pollen grains over pteridophytic spores, ratifying the results of macro-paleobotanical analyses.…”

Section: Introductionmentioning

confidence: 90%

“…The coalfield is actually located at downthrown structural blocks, mainly controlled by a N40 • E fault system, having its extent limited by subsequent erosion. The coalfield includes five coal seams ( interbedded with siltstones, mudstones, sandstones and paleosoils (Guerra-Sommer et al 2008b). The present study is based on fossil charcoal records recovered from a light gray clay bed approximately 7 to 10 cm thick identified as a tonstein layer and interbedded with the uppermost coal seam.…”

Section: Geological and Stratigraphic Settingmentioning

confidence: 99%

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Charcoal remains from a tonstein layer in the Faxinal Coalfield, Lower Permian, southern Paraná Basin, Brazil

Jasper

Uhl

Guerra-Sommer

et al. 2011

An. Acad. Bras. Ciênc.

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Fossil charcoal has been discovered in the Faxinal Coalfield, Early Permian, Rio Bonito Formation, in the southernmost portion of the Paraná Basin, Brazil. Three types of pycnoxylic gymnosperm woods recovered from a single tonstein layer are described and confirm the occurrence of paleowildfire in this area. A decrease of the charcoal concentration from the base to the top within the tonstein layer indicates that the amount of fuel declined during the deposition probably due to the consumption of vegetation by the fire. The presence of inertinite in coals overlying and underlying the tonstein layer indicates that fire-events were not restricted to the ash fall interval. The integration of the new data presented in the current study with previously published data for the Faxinal Coalfield demonstrates that volcanic events that occurred in the surrounding areas can be identified as one potential source of ignition for the wildfires. The presence of charcoal in Permian sediments associated with coal levels at different localities demonstrates that wildfires have been relatively common events in the peat-forming environments in which the coal formation took place in the Paraná Basin.

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Geochronological data from the Faxinal coal succession, southern Paraná Basin, Brazil: A preliminary approach combining radiometric U-Pb dating and palynostratigraphy

Cited by 58 publications

References 11 publications

Effect of volcanic ash-fall on a Permian peat-forming environment, on the basis of palynology, palynofacies and paleobotany (Faxinal Coalfield, Brazil)

Effect of volcanic ash-fall on a Permian peat-forming environment, on the basis of palynology, palynofacies and paleobotany (Faxinal Coalfield, Brazil)

Variation in stomatal numbers of Glossopteris leaves from the Lower Permian of Paraná Basin, Brazil

Charcoal remains from a tonstein layer in the Faxinal Coalfield, Lower Permian, southern Paraná Basin, Brazil

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