The tropical southern Atlantic Ocean climatic shifts and eco-system responses during the Paleogene-Quaternary along the Brazilian Margin.

Abstract

The Paleocene epoch showed short and extremely warm (hyperthermal) episodes.They are known as the Late Danian Event (LDE); the Danian/Selandian (D/S) event; the early-late Paleocene event (ELPE), also known as the mid-Paleocene biotic event (MPBE); and likely part of the long-lasting environmental disruption known as the Selandian-Thanetian Transition Event (STTE). Such prevailed warm and tropical climatic conditions were culminated during the Paleocene-Eocene Thermal Maximum (PETM) global warming event (55.8 Ma). This global warming event interrupted at the end of the early Eocene Climatic Optimum (EECO, ~49 Ma) by long-term cooling and arid trend, followed by the middle Eocene climatic optimum (MECO, ~40 Ma) global warming event which lasted ~500-600 kyrs. The Paleogene warming events was not equally distributed across the globe; it was intensive at the Northern mid, southern mid and high latitudes, coupled with increase in sea level, photic zone euxinia, global water anoxia expansion and an accelerated hydrological cycle while these environmental and ecological conditions remain unclear in several tropical open ocean regions due to the lack of sufficient records of low-latitude sediments. On the other hand, during the Quaternary period (2.6 Ma-Recent), there were remarked variations in the earth's orbit around the sun that resulted from insolation fluctuations of the planet (Milankovich theory) and resulted in major climatic changes that were translated by glacial and interglacial periods during the middle-Late Pleistocene. The Holocene Epoch (11,500 kyrs- Recent) is one of these interglacial stages. The Paleogene-Quaternary sediment archive cores along the Brazilian Margin will be used for multi-proxy biostratigraphic, paleoenvironmental and geochemical analysis for detecting the different global paleoclimatic events, the responses of the biotic assemblages and the paleoecological conditions prevailed in the tropical southern Atlantic Ocean during the Paleogene-Quaternary periods as main objectives of the current project.