Paleoenvironmental interpretation through the analysis of ostracodes and carbonate microfacies: study of the Jandaíra Formation, Upper Cretaceous, Potiguar Basin Interpretação paleoambiental por meio de análise das associações dos ostracodes e das microfácies carbonáticas: estudo da Formação Jandaíra, Cretáceo Superior, Bacia Potiguar

ABSTRACT: Paleoecological analyses are important tools for the reconstruction of paleoenvironments. This paper had the objective of using analysis of ostracode assemblages and carbonate microfacies of a well (Carbomil) and an outcrop (Quixere) from the Jandaira For-mation, Potiguar Basin, in order to verify how they corroborate and complement the other. Two paleoenvironments for Carbomil Well (assemblages 1 and 2, respectively marine and brackish to neritic en-vironments) and one for Quixere Outcrop (assemblage 3, marine en-vironment) were identified through the ostracode assemblage analy-sis. Thin section analysis allowed the identification of two different facies for Carbomil Well, i.e. bioclastic packstones to wackstones, a marine brackish or restricted marine system; and bioclastic grainsto-nes to packstones, a normal, shallow marine system. High levels of alteration on the samples prevented an adequate analysis of Quixere Outcrop; however, it seems to point towards a low-energy environ-ment. Overall, information provided by the thin sections corroborate and complement data of the ostracode assemblages, which allowed a higher degree of certainty for the paleoenvironmental analysis.