Late Holocene paleoclimate in the central Andes of Peru based on peatland record

The high central Andes have experienced significant hydroclimatic changes in recent decades, impacting ecosystems through glacier retreat, temperature variations, and altered precipitation seasonality. Andean peatlands are crucial to water and biogeochemical cycles and are sensitive to climate change. To infer past climatic and environmental conditions, we analyzed X-ray fluorescence (XRF) core scanning data, principal component analysis (PCA) with clr-transformation, and total organic carbon (TOC) on the APA01 peat core (basal age ~2500 years). PCA-clr explained 88.8% of variance, revealing interactions between organic matter (OM) content, accumulation dynamics, and climatic influences. The correlation between Log [S/Ti] and PC1-clr highlighted the interplay of OM concentration and erosion intensity. Environmental proxies such as Ln [Si/S] and Ln [Zr/Ti] ratios provided insights into accumulation processes and climatic impacts. Analysis of carbon accumulation rates (CAR) and mineral accumulation rates (MAR) from 507 BCE to 1565 CE indicated distinct phases of organic and mineral accumulation, reflecting climatic changes.

Comparative analysis with regional climate records (Quelccaya and Illimani ice cores, Pumacocha Lake sediments) during the Medieval Climate Anomaly (MCA) and Little Ice Age (LIA) demonstrated broader climatic influences on peatland dynamics. Decreased OM accumulation during the MCA was linked to drier conditions, while increased accumulation during the LIA corresponded to wetter climates. Warming phases such as the MCA, post-LIA, and recent decades showed high clastic mineral input without necessarily wetter conditions, likely due to glacier and permafrost melting and increased snow-to-rain proportion. Our data indicate a decline in peatland growth and OM accumulation since 2010, emphasizing the need for careful monitoring and future restoration efforts.