The impacts of volcanic eruptions and climate changes on the development of Hani peatland in northeastern China during the Holocene

Peatland development is closely correlated with regional environment and climate changes. In this study, two sediment cores covering the past 13.8 cal kyr BP were collected from Hani peatland in northeastern China. The organic content, carbonate content, Rb/Sr and Zr/Rb ratios were obtained to discuss the peat development process and associated environment and climate changes. The results showed that there were two deposition events in Hani peatland during 11.2–9.3 cal kyr BP and 2–1.4 cal kyr BP, when the organic content and Rb/Sr ratio decreased sharply, the carbonate content and Zr/Rb ratio increased dramatically. The synchronous occurrence of these two events and nearby volcanic eruptions, combining with tephra observed in sediments, indicated that volcanic activities have some impacts on the peat development. Except for the two events, the organic content of peat sediments increased gradually from the early to mid Holocene, and was highest at 8–6 cal kyr BP, then decreased gradually from the mid to late Holocene. The comparison with regional vegetation and paleoclimate records, together with the chemical weathering intensity obtained from the Rb/Sr, suggested that the orbital scale peat development in Hani during the Holocene was closely coupled with regional climate changes, including both temperature and precipitation. In addition, the 0.5–2 ka band filtering results of organic content showed similar oscillations with the drift ice indices of the North Atlantic Ocean and the atmospheric Δ¹⁴C record, implying that the North Atlantic climate and solar activities could also leave footprints on peat development of Hani on millennial timescale.