Humification degree of peat and its implications for Holocene climate change in Hani peatland, Northeast China

The humification degree of peat is a significant climatic proxy for paleoclimate change. Using the alkali-extraction method, a time series of absorbance values of the Hani peatland, Northeast China, was determined, which is used as an indicator for the humification degree of peat. Combined with ¹⁴C dating data of peat cellulose, and compared with δ¹⁸O and δ¹³C time series of the cellulose in the Hani peatland, the evidence for the existence of 14 ka paleoclimate was provided. Higher humification degrees hint a warmer-wetter climate, and vice versa. It also reconstructs the four stages of Holocene climate evolution in this region: 11.5–9.8 cal ka B.P., warm and wet period; 9.8–9.0 cal ka B.P., cold and dry period; 9.0–4.8 cal ka B.P., warm and wet period; and 4.8–0 cal ka B.P., warm-wet and dry-cold alternation period. Meanwhile, it is revealed that the abrupt climate shifts signals such as the “8.2 ka” event and the “4.2 ka” event. Results showed that the Hani peat humification degree is of sensitive response to paleoclimate change. Therefore, it is a feasible method to analyze the relationship between paleoclimate change and peat humification degree.