Pennsylvanian palynofloras from the Itu rhythmites (Itararé Subgroup, Paraná Basin) in São Paulo State, Brazil

详细信息    查看全文

• 作者：Paulo A. Souza ; Cristina M. F&#xe9 ; lix ; Annabel P&#xe9 ; rez-Aguilar ; Setembrino Petri
• 关键词：Palynology ; Paran&#xe1 ; Basin ; Itu ; Pennsylvanian ; Brazil
• 刊名：Revue de Micropaleontologie
• 出版年：2010
• 出版时间：April-June 2010
• 年：2010
• 卷：53
• 期：2
• 页码：69-83
• 全文大小：3379 K

文摘

The rhythmites of Itu present the best exposures of glacial varvites known in the Paraná Basin, and constitute a classic geological monument related to the Late Palaeozoic Gondwanan glaciation. Palynological results in this paper are based on rhythmites from two quarries in Itu area, central-eastern State of São Paulo, Brazil, including correlate levels of the “Itu Varvite Park”, as well as based on samples from the borehole IT-IG-85 (at 171 and 228 m) drilled also in the Itu City. Well-preserved indigenous miospores and microphytoplankton elements have been recorded. The former comprise 15 spore species and 19 pollen species, of which three are recorded for the first time in the Brazilian part of the Paraná Basin (Verrucosisporites cf. V. andersonii, Convolutispora archangelskyi and Caheniasaccites verrucosus). Microalgae include prasinophyceans (Leiosphaeridia sp., Tasmanites sp., Deusilites tenuistriatus), chlorophyceans (Botryococcus braunii) and zignemataceans (Tetraporina). The palynological content confirms a late Pennsylvanian (Kasimovian/Gzhelian) age for these rhythmites, which are assigned to the Crucisaccites monoletus interval Zone, based on the record of the eponymous pollen species and Scheuringipollenites maximus. Although very scarce, prasinophycean algae suggest low salinity marine conditions.