RECENT ADVANCES IN CARBONIFEROUS PALYNOLOGY FROM WESTERN ARGENTINA

CÉSARI, S.N.; PEREZ LOINAZE, V.S.

Florianopolis, Brasil

Simposio; XII Simpósio de Paleobotânicos e Palinólogos; 2009

Asociación Latinoamericana de Paleobotánica y Palinología

During the last years studies on Carboniferous sequences from western Argentina increased noticeably the palynological knowledge of this Gondwanic region. Early Carboniferous assemblages from Rio Blanco Basin were revised on the basis of many samples coming from different stratigraphic levels of the Angualasto Group. Palynofloras from the Cortaderas Formation allowed the improvement of the previous biostratigraphic scheme with the definition of the Late Visean MQ Biozone. Assemblages obtained from diamictites exposed at the top of Cortaderas Formation contain diagnostic species that support the recognition of the Late Visean glacial episode in this part of Gondwana. An abrupt paleofloristic change is recognized in the passage from the Serpukhovian assemblages to the overlying associations of the Guandacol Formation. The floristic change is marked by the sudden and abundant incoming of monosaccate pollen together with the occurrence of Cordaitales in the macrofossil record. The lowermostpart of the Guandacol Formation is characterized by diamictites from which were recovered, for the first time, abundant palynological associations. These deposits characterize the Serpukhovian glacial event in western Gondwana. Glacigenic sediments from the Malanzán (Sierra de Los Llanos), Agua Colorada (Sierra de Narváez), Jejenes and Rio Francia (Precordillera) formations together with the El Imperial and Agua de Jagüel Formations (Mendoza Province), were sampled and provided abundant palynological associations. An analysis of the distribution of the species present in the glacial and postglacial sediments, will enable better characterization of the Sub-biozones A and B of the DM Biozone. A refinement of the worldwide correlations will be possible.