Late Quaternary deglaciations in the western tropical Atlantic and eastern tropical South AmericaLate Quaternary deglaciations in the western tropical Atlantic and eastern tropical South America

Deglaciations are periods in Earth’s geological history marked by the transition from glacial to interglacial climates. Recent research has increasingly focused on identifying similarities and differences among terminations, particularly the role of millennial-scale climate variability. These transitions are marked by episodes of a weakened Atlantic Meridional Overturning Circulation (AMOC), with widespread climate impacts. Observational data suggest that the AMOC may be weakening at present due to human-induced climate change, reinforcing the importance of terminations as case studies for understanding climate behavior under reduced AMOC, global warming, global ice loss, and monsoon changes. This study compares the evolution of Terminations V (ca. 430 ka), II (ca. 135 ka), and I (ca. 20 ka) from a paleoceanographic and paleoclimatic perspective based on marine sediment cores from the western tropical Atlantic. Sea surface temperature and salinity, bottom-water ventilation, and continental precipitation over the adjacent tropical South America will be reconstructed. For this purpose, we are conducting stable oxygen and carbon isotope analyses on planktonic and benthic foraminifera, Mg/Ca analyses on planktonic foraminifera, and X-ray fluorescence analyses on bulk sediment. Our goal is to identify specific patterns of climatic variability among these terminations, focusing on regional and global ocean-atmosphere responses. These results may improve our understanding of the dynamics of rapid climate transitions and their effects on the tropical Atlantic, as well as provide insights into potential present-day climate responses to AMOC weakening. Preliminary results will be presented. [FAPESP grants 2022/06452-0, 2024/11054-9, 2024/00949-5, 2025/19613-0 and 2025/05117-0].