Palynology (fungi and fern spores, gimnosperm pollen grains, algae cysts and scolecodont) from the solimões and içá formations (neogene and pleistocene, solimões basin), Amazonas, Brazil Rosemery Rocha da SILVEIRA, Paulo A. SOUZA Pesquisas Em Geociencias, 2016 O conhecimento palinológico dos depósitos das formações cenozoicas da Bacia do Solimões tem sido substancialmente aprimorado nas últimas décadas, a partir de materiais de subsuperfície, bem como de afloramentos. Este trabalho apresenta parte dos resultados taxonômicos do estudo de 93 amostras oriundas de 12 afloramentos das formações Solimões e Içá, na região de Coari (cinco afloramentos), e Alto Solimões (sete afloramentos), estado do Amazonas, Brasil, que revelaram conjuntos palinológicos abundantes, diversificados e bem preservados. Aqui são listadas e ilustradas 53 espécies de palinomorfos, compreendendo 11 espécies de esporos de fungos, 31 de esporos de pteridófitas e dois de grãos de pólen de gimnospermas, oito de algas (sete clorofíceas e uma dinofícea), e um de escolecodonte, com descrições quando necessário. A composição palinológica é distinta para as duas áreas analisadas, tendo na região do Alto Solimões documentação de formas como Crassoretitriletes vanraadshooveni, Foveotriletes ornatos, Magnastriatites grandiosus e a ocorrência de um cisto de dinoflagelado. Na região de Coari foi verificado predomínio de esporomorfos, com grande diversidade e abundância de esporos de fungo e pteridófitas.
Neogene-Quaternary sedimentary and paleovegetation history of the eastern Solimões Basin, central Amazon region Afonso César Rodrigues Nogueira, Rosemery Silveira, José Tasso Felix Guimarães Journal of South American Earth Sciences, 2013 Palynological and stratigraphical analyses were carried out on the outcrops of the Solimoes River to present new information about freshwater paleoenvironments of a fluvial–deltaic and meandering river system, evaluate the vegetation changes in the upper Solimoes and Ica Formations in the eastern Solimoes Basin, and the role of the Purus Arc in the evolution of central Amazon during the upper Neogene. The upper Miocene to Pliocene Solimoes Formation is related to a fluvial–deltaic system, with fine-grained sediments of the prodelta–lacustrine environment supplied by meandering distributaries and delta front environment. The lake and distributaries were surrounded by extensive deltaic and floodplains colonized by lowland freshwater forests under wet climate conditions, persisting until the Pliocene. The Ica Formation started to deposit unconformably on the Solimoes Formation during the Pleistocene, following the development of extensive meandering channels surrounded by floodplains of an essentially fluvial system linked to development of the present eastward direction of the Amazon River until the Atlantic coast. These floodplains were colonized by few palm species and pteridophytes of lowland freshwater forests during the Pleistocene. Additionally, no algae and fungi were observed, which may be related to drier climate conditions and/or different morphological conditions than the upper Solimoes Formation.
Fossil fungi from miocene sedimentary rocks of the central and coastal Amazon Region, North Brazil José Tasso Felix Guimarães, Afonso César Rodrigues Nogueira, José Bandeira Cavalcante Da Silva, Joelson Lima Soares, Rosemery Silveira Journal of Paleontology, 2013 Samples from outcrops of the Miocene Solimões and Barreiras formations from the central and coastal Amazon regions of Brazil were analyzed palynologically. Assemblages of fossil fungi were identified, and are described herein, and their relevance to paleoenvironmental and paleoclimatic studies in tropical regions discussed. The fungal assemblage comprises four spore groups, 19 species belonging to 12 genera. Additionally, two new species are proposed. The samples from the Solimões Formation contain the following taxa: Mediaverrunites elsikii, Mediaverrunites mulleri, Monoporisporites sp., Fusiformisporites crabbii, and Multicellites cingulatus. The presence of these suggests river channel margins colonized by freshwater vegetation, where seasonal fluctuations of water table and rainfall produce wetter substrates. The samples from the Barreiras Formation showed higher species and generic diversity than those from the Solimões Formation with Hypoxylonites minutus, Hypoxylonsporites ater, Hypoxylonites sp., the new species Inapertisporites multiporus n. sp., Pluricellaesporites regularis, Lacrimasporonites levis, Monoporisporites annulatus, Spirotremesporites simplex, Dyadosporites novus, Dyadosporites sp., and Multicellaesporites attenuates. All of these correspond to parasitic fungi from a range of from tropical wetlands. Spegazzinites sp. and Dicellaesporites aculeolatus, good indicators of marine influence and mangrove presence, were also identified in the samples from the Barreiras Formation. Furthermore, the fungal spore taxa Inapertisporites multiporus, Mediaverrunites elsikii, Mediaverrunites mulleri, Pluricellaesporites regularis, and Spirotremesporites simplex serve as stratigraphic indicators when combined with miospore index taxa such as Crassoretitriletes vanraadshooveni, Grimsdalea magnaclavata and Fenestrites longispinosus indicating a Miocene age for these sediments in the Amazon region.
