CICYTTP   12500
CENTRO DE INVESTIGACION CIENTIFICA Y DE TRANSFERENCIA TECNOLOGICA A LA PRODUCCION
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
New palynological and floral information from the Potí Formation (late Viséan), Riacho do Roncador creek, Parnaíba Basin, northern Brazil
Autor/es:
IANNUZZI, R.; DI PASQUO, M.M.
Lugar:
Lisboa
Reunión:
Congreso; 1st International Congress on Stratigraphy (STRATI 2013); 2013
Institución organizadora:
Department of Earth Sciences and the Research Centre in Geological Science and Engineering, of the Faculty of Science and Technology, Universidade Nova de Lisboa (New University of Lisbon).
Resumen:
The aim of this contribution is to present the first
palynological assemblage recovered from surface deposits of the Poti Formation
cropping out in the Riacho do Roncador, northeastern Brazil. The lower Pennsylvanian
Piaui Formation unconformably overlies this unit, and unconformably is underlain
by the Longá Formation. The Potí Formation consists mainly of sandstones with
minor proportions of carbonaceous shales and other siliciclastic lithologies in
part fossiliferous, containing plant remains, bivalves, and palynomorphs of
early late Visean age. The formation accumulated in fluvial to marine
environmental settings. From an outcrop of 5 m thick, five carbonaceous shales and siltstones
(3m thick) yielded diverse and abundant well-preserved palynomorphs. The
assemblage is composed of 62 indigenous species, of which 57 are spores and 5 are algae, and 32 are
reworked species (9 spores and 23 microplankton). First records for the Mississippian of Brazil and South
America are also recorded. Stratigraphically significant
species, some of them not previously recorded in subsurface investigations,
include: Anapiculatisporites concinnus,
Tricidarisporites phippsae, Punctatisporites subvaricosus, Foveosporites
pellucidus, Grandispora maculosa, Knoxisporites ruhlandi, Verrucosisporites
morulatus, Retusotriletes mirabilis, Waltzispora polita, which confirm the
late Visean age of the Mag Zone Melo and Loboziak. Worldwide comparison of the
Brazilian association indicates greater affinity with coeval palynofloras from
Gondwana region (South America and North Africa) and North
America. The degree of similarity is likely to be determined by
paleolatitude. Sedimentologic features along this section clearly reflect
depositional environments between brackish deltaic to estuarine facies. The
dominance of Botryococcus with
varied morphologies throughout this section, the presence of reworking
restricted to the uppermost level and the plant remains found into the basal
part, support this interpretation.