Biostratigraphy and paleoecology of an unusual palynological record from the Aquidauana Formation, Late Pennsylvanian of Paraná Basin

Abstract

The Aquidauana Formation is a Permo-Carboniferous sedimentary unit, widely stratigraphicaly distributed in the northwestern and northern portions of the Paraná Basin. However, little paleontological data is available from this formation, preventing accurate biostratigraphic and paleoecological interpretations. An abundant, diversified and well preserved assemblage of palynomorphs was recognized from sampling conducted in an outcrop section in Cipolândia District of Aquidauana Municipality, state of Mato Grosso do Sul, Brazil. A total of 35 indigenous palynomorph taxa was recognized, comprising 6 species of spores (related to 5 genera), 28 species of pollen grains (14 genera) and 1 species of chlorophycean algae. Monosaccate pollen grains are exceptionally dominant, representing 90.38% of the association, particularly constituted by species of the genera Cannanoropollis (30.41% of the total assemblage), Potonieisporites (28.14%) and Plicatipollenites (19.52%). This quantitative overrepresentation is not usual from Gondwana deposits, revealing a particular plant dominance of Cordaitales in the terrestrial flora. These results are interpreted as an upland ecology characterized by plants with a moisture-independent reproduction strategy, under a glacial climate influence. Certain species of pollen allow assignment of this assemblage to the Crucisaccites monoletus Zone (Late Pennsylvanian), which had been recognized only in the middle portion of the Itararé Group at the northeastern margin of the basin.

First Palynological Record from the Upper Carboniferous/Lower Permian Succession in West Beni Suef Basin, Egypt, with Paleoecological and Paleogeographical Implications

“…This finding could be attributed to a lacustrine flooding resulting from minor deglaciation events that could decrease/prevent the lowland spore-producing plants' persistence, thereby increasing the upland flora's representation (Stephenson & Osterloff, 2002). This finding is consistent with the results obtained from various Gondwanan basins by Azcuy (1979), Playford & Dino (2000) and Souza et al (2015) for South America; by Tiwari & Tripathi (1992) and Srivastava & Agnihotri (2009) for India; by Lindström (1995) for Antarctica; and by Balme (1980), Backhouse (1991) and Jones & Truswell (1992) for Australia (Souza et al, 2015 and references therein). However, the percentage of Cycadopsida in the uppermost sample from the horizon at 1362m increased slightly compared with that of the deeper samples (from 4% to 16%).…”

“…According to the obtained palynological data, we can conclude that two paleofloral types occurred in the Beni Suef Basin during the Late Carboniferous and Early Permian: a lowland paleoflora that was represented by a cold climate wetland fern community co-occurring frequently with Lycopsida, Sphenopsida and Cycadopsida vegetation; and an upland paleoflora that was dominated by a primitive group of conifers that produce monosaccate pollen (Cordaitanthales and Coniferales). This group mainly occupied relatively arid highlands because they have a unique moisture-independent reproductive strategy that enables them to tolerate the physiological drought that occurred in moisturedeficient or well-drained environments (Stephenson & Osterloff, 2002;Stephenson et al, 2005;Souza et al, 2015). In the present study, the upland flora's percentage increased compared with that of the lowland flora.…”

“…The dominance of monosaccate pollen grains (Potonieisporites, Plicatipollenites and Florinites) combined with the low frequency of taeniate pollen grains (Protohaploxypinus) confirms a late Pennsylvanian age (Westphalian-Stephanian; 306.5-299 Ma) as documented in various Gondwana basins in Brazil (Souza 2006;Souza et al 2015), Libya (Brugman et al, 1988;Loboziak & Clayton, 1988), Saudi Arabia and Oman (Love, 1994;Owens & Turner, 1995) and Australia (Kemp et al, 1977). Taeniate pollen grains first appear in the Moscovian (Westphalian), thus confirming a post-Westphalian age (e.g., Inosova et al, 1976;Souza, 2006;Souza et al, 2015), and this pollen has shown a continuous abundant and diverse presence since the Asselian (Early Permian) of both the Euramerican and Gondwanan provinces (Inosova et al, 1976;Kemp et al, 1977). A similar palynoevent as the monosaccate acme was recorded in Oman, Yemen and Pakistan during the Late Carboniferous (Kasimovian-Gzhelian; 307-298.9 Ma) (Stephenson et al, 2003;Stephenson, 2006;Jan & Stephenson, 2011;Stephenson et al, 2013).…”

Palinomorfos e associações de fácies da Formação Lagoa Azul (Grupo Itararé, Pennsilvaniano da Bacia do Paraná) no sudeste do Estado do Paraná, Brasil

“…Urban 1971 (ocorrente no nível CT1a do afloramento de Campo do Tenente) é restrita à ZAc. Contudo, há que se observar que esta mesma espécie ocorre também na Formação Aquidauana, no estado do Mato Grosso do Sul, em associação atribuída à Zona Crucisaccites monoletus (Souza et al, 2015), típica da Formação Campo Mourão (porção média do Grupo Itararé), o que requer melhor análise do zoneamento de Souza (2006) e do significado bioestratigráfico desta espécie.…”

“…Isto implica uma idade incluída no intervalo Neobashkiriano ao Kasimoviano e uma correlação bioestratigráfica da seção de estudo da Formação Lagoa Azul com a porção inferior do Grupo Itararé (Souza, 2006;Holz et al, 2010). Contudo, a constatação de Costatascyclus crenatus na Formação Aquidauana no Estado do Mato Grosso do Sul por Souza et al (2015), com associação característica da ZCm requer reanálise do zoneamento de Souza (2006), ainda que esta zona tenha sido proposta para o Grupo Itararé nos estados de São Paulo e Paraná, o que poderia refletir em distintas distribuições das espécies guias em áreas fora desta abrangência.…”