An accurate record of volcanic ash fall deposition as characterized by dispersed organic matter in a Lower Permian tonstein bed (Faxinal Coalfield, Paraná Basin, Brazil)
Simas, M. W. (Universidade Federal do Rio Grande do Sul (UFRGS). Instituto de Geociências)
Guerra-Sommer, M. (Universidade Federal do Rio Grande do Sul (UFRGS). Universidade Federal do Rio Grande do Sul (UFRGS))
Mendonça, J. G.
Cazzulo-Klepzig, Filho M. (Universidade Federal do Rio Grande do Sul (UFRGS). Instituto de Geociências)
Formoso, M. L. L. (Universidade Federal do Rio Grande do Sul (UFRGS). Instituto de Geociências)
Degani-Schmidt, I. (Universidade Federal do Rio Grande do Sul (UFRGS). Instituto de Geociências)

Fecha:	2013
Resumen:	For the first time, the dispersed organic matter in the tonstein layer interbedded with a coal seam in the Faxinal Coalfield (Sakmarian, Southern Paraná Basin, Brazil) is characterized. The deposition of clusters of pollen grains was highly influenced by the intense ash fall process that probably occurred during seasonal dehiscence of reproductive structures. The well-preserved phytoclasts with their upper and lower leaf cuticles stuck together indicate that the rapid fall of ash on this material hindered organic biodegradation. The preservation of seemingly autochthonous Botryococcus colonies at the top of the tonstein layer is evidence of the subaqueous deposition of this layer. The darkening in cuticles and xylem phytoclasts can be attributed to different causes: the thermal influence of ash fall during deposition, chemical effects of the ash, prolonged oxidation of organic matter in low water level conditions or the burning of plant organs by wildfires. Analyses of dispersed organic matter along the tonstein layer showed that the organic matter succession reflects the composition of different plant strata (herbaceous pteridophytes and arboreal glossopterids-cordaitaleans) around the deposition site.
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Tonstein ; Organic matter ; Volcanic ash fall ; Southern Paraná Basin
Publicado en:	Geologica acta, Vol. 11, Núm. 1 (març 2013) , p. 45-57, ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/263717
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/105.000001835
DOI: 10.1344/105.000001835

14 p, 2.1 MB

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