TAPHONOMY OF PALYNOLOGICAL RECORDS IN A SEQUENCE STRATIGRAPHIC FRAMEWORK - AN EXAMPLE FROM THE EARLY PERMIAN PARANA BASIN OF SOUTHERN BRAZIL

An Early Permian succession has been studied From the viewpoint of seq uence stratigraphy, in ail area approximately 10.000 km(2) wide, locat ed at the northeastern region of Rio Grande do Sul State (Brazil). Thi s research is based on data acquired From 92 entirely cored boreholes, each with lithological/geophysical logs and cores supplied by the Bra zilian Agency CPRM. The chronostratigraphic framework, which consists of four third-order sequences, is compared to pollen and spore percent age curves, in order to test whether major variations in the palynolog ical record are related to changes in relative sea level, as defined b y detailed sequence stratigraphic analysis. The results conclusively s hows that transgressive surfaces and maximum flooding surfaces have a distinct palynological signature. Lon stands have a high spore content . while transgressive systems tracts have a gradually decreasing spore record. Some specific conclusions include the following : the highsta nd system of sequence III is marl;ed by the appearance of abundant acr itarchs. Forms of Botryococcus, previously considered to be a freshwat er alga, are recorded in the transgressive systems tracts of every map ped sequence, which suggests a broader paleoecological occurrence for this genus than documented until nom in the literature. (C): 1998 Else vier Science B.V.