Foraminíferos da Formação Calumbi, Bacia de Sergipe-Alagoas e suas correlações com os eventos descritos para o Cretáceo Superior

Abstract

Paleoecology is an important area of Ecology that consists of applying ecological knowledge and theories to the environments of the past through the analysis of fossil organisms. The Cretaceous period is much studied because its climatic condition has been defined as very similar to the greenhouse effect. The Calumbi Formation - Sergipe Alagoas Basin, belongs to the Upper Cretaceous and is associated to large geological events that interfered in the environmental conditions for the period. The present work aims to determine how these events described for the Cretaceous occurred for the Calumbi 01 outcrop through the identification of fossil forms of foraminifera and paleoecological analyzes. About 300 foraminifera were identified for each sample collected in the Calumbi 01 outcrop, located at 10.882900 ° S, 37.117405 ° W, WGS 84, Nossa Senhora do Socorro, SE-Brazil. The material was removed from three levels, named Superior, Intermediate and Lower. From the results of the analysis of the ecological indexes and Beta diversity, in addition to the analyzes made for the oxygen index of each level from benthic foraminifera, it was verified that the three levels present significant differences between them and that they were oxygenated environments, Although the most abundant species are classified as suboxic and are related to environments with low amounts of oxygen, which may infer that these environments suffered from resurgence and transgression events. Depth and temperature were also analyzed from planktonic forms, indicating shallow and warm environments. Despite the difficulties in defining ecological and habitat preferences for the identified species, it was possible to define the paleoecological characteristics for outcrop 01 of the Calumbi Formation.