G05_P08

Peatland initiation and carbon accumulation history during the Holocene in Xinjiang, China

Zhao H^1,2,3,  Zhou W^1,2,4,5,6,7, Cheng P^1,2,5,6, Du H^1,2, Xian F^1,2,4, Shu P^1,2

¹The State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China, Xi'an, China, ²Shaanxi Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi’an, 710061, China, Xi'an, China, ³Xi’an Institute for Innovative Earth Environment Research, Xi'an, China, ⁴CAS Center for Excellence in Quaternary Science and Global Change, , China, ⁵Xi’an Jiaotong University, Xi'an, China, ⁶Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China, ⁷Beijing Normal University, interdisciplinary Research Center of Earth Sciences, Beijing, China

Peatland ecosystems are important terrestrial carbon reservoirs, understanding the responses of carbon dynamics to climate change will provide useful insights into projecting the fate of peatland carbon in the future. Most studies about the carbon dynamics of peatlands were focused on boreal and tropical peatlands now. However, there are rare data about carbon dynamics in the Xinjiang region, which is sensitive to climate change. Here, we studied the carbon accumulation histories during the Holocene by measuring the radiocarbon ages, total organic carbon(TOC), and bulk dry density(BDD) at Halashazi(ALT, 48°06′58.2′′N, 88°21′50.8′′E, 2456.7 msl) and Tielishahan peatlands(KNS, 48°48′87.4′′N, 86°54′60.0′′E, 1766.5 msl) in the Altay mountains. The result indicates a rapid carbon accumulation (averages are 98.4 and 107.2 g C/m²/yr in ALT and KNS profile, respectively) happened in the early Holocene(10.5-8.4ka), then carbon accumulation deposition flux decreased (59.9 and 60.4 g C/m²/yr) during the mid-Holocene(8.4-4.2ka), after that, it significantly elevated(58.1 and 69.9 g C/m²/yr) during the early late-Holocene(4.2-2.0ka), followed by a rapid decline(only recorded in KNS profile with the average of 71.9 g C/m²/yr) at the end of late Holocene(after 2.0ka). Systematic analysis with 51 basal ages of peatlands in Xinjiang also suggested the fast peat initiation during the early Holocene and late Holocene. The peatland initiation and accumulation histories in Xinjiang are linked with the temperature records, suggesting the possible causal connection between peatland dynamics and local temperature. Furthermore, the fast initiation and accumulation of peat during the late Holocene might have contributed to high atmospheric carbon dioxide concentrations.