oa South American Summer Monsoon Variability and Water Stress Reconstruction Over Glacial-Interglacial Timescales

Climate variability over glacial-interglacial timescales is not well characterized in the tropical Andes, and paleoclimate records are lacking in this region. To offset this gap, we analyzed organic compounds from sediment cores retrieved from Lake Junin (central Peruvian Andes) to better understand climate variability in the region since the LGM, with a focus of South American Summer Monsoon (SASM) intensity, changes in temperature, and water stress. We measured the hydrogen and carbon isotopic composition (dD; d13C) of long and mid-chain n-alkanes (nC29 – terrestrial and nC23 – aquatic) to characterize changes in the intensity of the South American Summer Monsoon (SASM) and evaporative enrichment of lake water. We used ?Aquatic-terrestrial as a water stress indicator, focusing on the sensitivity of the region to changes in monsoon intensity. Our results suggest that SASM intensity is controlled by insolation intensity in the southern hemisphere (11 °S). More importantly, there is a tight coupling between the position of the ITCZ, and the intensity of the SASM. We also assessed trends in temperature change using brGDGTs, which suggest a consistent regional climate signal. We also aim to explore monsoon variability during MIS 7 and 11 to explore monsoon response to different boundary conditions.