Peat development in the Napahai wetland and its response to variations in the intensity of the Indian summer monsoon, southwestern China, since the last deglaciation

Knowledge of peatland dynamics and its response to the intensity of the Indian summer monsoon (ISM) is crucial to predict the future fate of the peatlands in the southwestern China under climate warming scenarios. In this study, we obtained a sediment core from the Napahai wetland in southwestern China and analyzed geochemical indices, including loss on ignition at 550 degrees C, carbonate content, as well as magnetic susceptibility, and ash-free bulk density, to investigate the peatland development since the last deglaciation. Results show that peat formation at ca. 13.3 cal. kyr BP in the Napahai wetland was likely attributed to climate warming during the Bolling-Allerod period. The results clearly suggest the peat continuously accumulated from 13.3 to 7.2 cal. kyr BP and weakened from the Middle to Late Holocene (7.2-1.5 cal. kyr BP), indicating notably wet conditions during the Early to Middle Holocene (11.8-7.2 cal. kyr BP) and a clear long-term drying trend in the Middle to Late Holocene. A comparison of the Napahai records with other monsoon intensity and related hydroclimatic records in areas dominated by the ISM suggests that the development of the Napahai peatland at orbital-suborbital timescales corresponded to the variations in the ISM intensity and the summer insolation.