The early Paleogene sedimentary record of the Sao Paulo Plateau holds the key to understanding the timing and mechanisms of the onset of Atlantic oceanic circulation, with implications for ocean – climate feedback systems. The timing and evolution of South Atlantic Ocean connectivity remain poorly understood, hindering a full understanding of modern circulation mechanisms. In this work, we develop an improved magnetostratigraphic age model for the late- Cretaceous to Eocene sedimentary record of Deep-Sea Drilling Project (DSDP) Site 356, located on the São Paulo Plateau at the edge of the Rio Grande Rise. The model constrains the timing of the beginning of Atlantic Ocean circulation, as the last obstacle to a connected Atlantic was removed. We use the age model to quantify sedimentary rates, and correlate with rock magnetic and published geochemical data to explore links between ocean current rearrangement and climatic anomalies. We find that periods characterized by variations in the magnetic properties of sediments and sedimentation anomalies in the Sao Paulo Plateau are reflected in carbon isotope events, supporting a possible link between ocean circulation and hyperthermal events.

圣保罗高原的古近纪早期沉积记录是理解大西洋海洋环流发生的时间和机制的关键，这对海洋-气候反馈系统具有重要意义。对南大西洋连通性的时间和演变仍然知之甚少，这妨碍了对现代循环机制的充分理解。在这项工作中，我们开发了一个改进的地层年龄模型，用于位于里奥格兰德河谷边缘圣保罗高原的深海钻探项目（DSDP）站点356的白垩纪至始新世沉积记录。该模型限制了大西洋环流开始的时间，因为消除了连接大西洋的最后一个障碍。我们使用年龄模型来量化沉积速率，并与岩石磁性和已发布的地球化学数据相关联，以探索洋流重排与气候异常之间的联系。我们发现，以碳同位素事件反映了以沉积物的磁性特征变化和沉积异常为特征的时期，这反映了碳同位素事件，支持了海洋环流与高温事件之间的可能联系。