Vila Maria Formation (Silurian, Paraná Basin, Brazil): integrated radiometric and palynological age determinations
AUTOR(ES)
Mizusaki, Ana Maria Pimentel
DATA DE PUBLICAÇÃO
2011
RESUMO
Fresh shale samples taken from a well-known outcrop section of the Silurian Vila Maria Formation, located on the northeastern margin of the Paraná Basin (Três Barras Farm, Goiás State, central-western Brazil), have been analysed for both palynological and radiometric age determinations. The rocks yielded a fairly diverse, age-definitive cryptospore assemblage, and the same samples proved suitable for Rb–Sr analysis, despite Silurian sedimentary rocks being rarely suited to radiometric dating techniques. This study thus introduces an alternative, independent method for estimating the minimum depositional age of the Vila Maria Formation. The Rb–Sr age value has been calculated via an isochron diagram that yields 435.9±7.8 Ma. Accordingly, the latter value is interpreted as the minimum depositional age of the analysed Vila Maria strata, implying their deposition during Llandovery times. This concurs with the palynological results, which indicate an age no older than Early Silurian and, more particularly, favour an Early to Middle Llandovery (Rhuddanian–Early Aeronian) attribution.
ASSUNTO(S)
bioestratigrafia : bacia do parana silurian absolute age palinologia siluriano palynology biostratigraphy parana basin
ACESSO AO ARTIGO
http://hdl.handle.net/10183/27444Documentos Relacionados
- Quaternary colluvial episodes (Upper Paraná River Hydrographic Basin, Brazil)
- Facies, 3rd order sequence stratigraphy and hydrologic potential of sandstones, Mafra Formation (late Paleozoic), Paraná Basin, Brazil
- Allometric scaling and heterochrony in Mesosaurids (Amniota, Sauropsida) from the Irati Formation (Permian of the Paraná Basin, Brazil)
- Diplognathodus occurrence in the Itaituba Formation, Amazonas Basin, Brazil
- Biostratigraphy and paleoecology of an unusual palynological record from the Aquidauana Formation, Late Pennsylvanian of Paraná Basin