Menardiiform planktonic foraminifera stratigraphy from Middle Pleistocene to Holocene in the Western South Atlantic

We studied the Middle Pleistocene to Holocene menardiiform planktonic foraminifera (MPF) stratigraphy in six continuous deep-sea sediment cores recovered from the Brazilian continental slope to evaluate its use in climatic characterization and as a reliable biostratigraphic tool in the western South Atlantic. For this purpose, an important issue was to construct a robust local biochronological framework for the past 772 ky in the western South Atlantic (Santos Basin). The oxygen isotope chronostratigraphic control allowed us to recalibrate the MPF events in the Santos Basin and identify diachronous bioevents. The bio-horizons found in the Santos Basin, such as the V/W and T/U (bio)zone boundaries, were found in a different chronostratigraphic position compared to previous studies. Results indicate that typical cyclic disappearances and reappearances of the MPF are not synchronous throughout the Atlantic Ocean and should not be employed for ‘climatic zonation’. This asynchronous evidence also provides information on the timing of the mechanisms responsible for the proliferation of these species throughout the Atlantic Ocean. Therefore, we strongly recommend that a local biochronological framework should be used for inter-basin comparisons and also accumulation rate estimates, both for paleoclimatic studies and continental slope geohazard assessment. © 2018, Sociedade Brasileira de Paleontologia. All rights reserved.