Ostracods from the late Albian-early Cenomanian of the Sergipe-Alagoas Basin, Brazil: New taxonomic and biostratigraphic inferences

摘要

This paper presents new taxonomic reports and biostratigraphic inferences based on ostracods in the basal section of the cored well UFRJ-2-LRJ-01-SE, perforated in the Votorantim quarry, Sergipe-Alagoas Basin, Brazil. The studied material comprised 44 samples in the range 438.65 to 315.30 m, identifying 52 species of ostracods distributed in 31 genera and 16 families. Five new species are proposed: Aracajuia separatta sp. nov.; Cytheropteron laranjeirensis sp. nov.; Microxestoleberis riachuelensis sp. nov.; Parahemingwayela fauthi sp. nov. and Quasihermanites? punctata sp. nov. The age of the studied interval was established by the occurrence of Aracajuia antiqua (MSA-1) between 434.00 and 347.25 m indicating the upper Albian. The first occurrence of Bythoceratina tamarae marks the upper Albian-lower Cenomanian boundary at 315.30 m. The biozones proposed with ostracodes coincides with the biozones of calcareous nannofossils made found at cored well.