Palinologia da formação Codó (Aptiano) na região de Codó, Nordeste da Bacia do Parnaíba

Abstract

The present study focused on the palynological results obtained from quantitative and qualitative analyses of sedimentary strata from drilling hole 9-PIF-4A-MA, corresponding to the Codó Formation, close to the Codó region, northern portion of the Parnaíba Basin, State from Maranhão. The deposits of this formation form a sequence composed of sandstones and shales, with intercalations of carbonates and evaporites, where its shales are known for their significant potential for generating hydrocarbons. Palynological analyses were carried out on 11 core samples, which resulted in identifying 32 species of palynomorphs, predominantly of continental origin. Among these palynomorphs, the guide species Equisetosporites maculosus stands out, whose presence limits the strata to the Sergipea variverrucata palynozone (P-270), confirming the upper Aptian age usually attributed to the strata of the Codó Formation. Likewise, quantitative analyses, showing a predominance of the genera Classopollis, Gnetaceaepollenites, and Equisetosporites, reveal that the deposition of sediments occurred mainly in a fluvio-lacustrine environment under a paleoclimate characterized by arid to semi-arid conditions.