Advances in Earth Science ›› 2012, Vol. 27 ›› Issue (1): 42-51. doi: 10.11867/j.issn.1001-8166.2012.01.0042

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Advances in Palaeoclimatic Research Recorded by Peat in China since the Last Deglaciation

Zhang Junhui 1,3,Xia Dunsheng 1,2,Zhang Ying 1,Liu Yuhang 1   

  1. 1.Research School of Arid Environment & Climate Change, Lanzhou University,Lanzhou730000, China;
    2. Key Laboratory of Desert and Desertification,Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences,Lanzhou730000,China;
    3.Key Laboratory of Disaster Monitering & Mechanism Stimulating Baoji University of Arts and Sciences,Baoji721016, China
  • Received:2011-04-28 Revised:2011-11-03 Online:2012-01-10 Published:2012-01-10

Zhang Junhui,Xia Dunsheng,Zhang Ying,Liu Yuhang. Advances in Palaeoclimatic Research Recorded by Peat in China since the Last Deglaciation[J]. Advances in Earth Science, 2012, 27(1): 42-51.

Studies of palaeoclimatic and paleoenvironmental evolution recorded by peat are one of the important research areas of past global change. As for these studies since the last deglaciation in China, the works have mainly concentrated on eastern monsoon regions, especially Hani region in Northeast, Zogie-hongyuan in the Qinghai-Tibetan Plateau, Dajiuhu in Shennongjia basin and the Dahu swamp in South China, totalizing four districts. The research results on the above four areas which are characterized by high-resolution integrated information on peat deposits reveal the spatiotemporal features of climate change during the research period, i.e. there were not only consistencies of changes on temperature and humidity, but regional differences in research areas. The climate in the northeast, the eastern and southern mountain areas was displayed on a cold wet weather, whereas that in the Qinghai-Tibet Plateau was cold and dry during the last deglaciation period. However, after the Younger Dryas(YD)event, warm and wet were the main climate features in the Qinghai-Tibet plateau, the eastern and southern mountain areas during the early and middle Holocene, while in the northeastern regions the effective precipitation decreased and the climate took on a dry trend in the late Holocene. Since the last deglaciation, another remarkable feature reflected by the peat records from the eastern monsoon region has been the frequent fluctuations on temperature and precipitation, and that from Hongyuan and Hanni regions reveals there were some dry-cold events in Qinghai-Tibet plateau and the Northeast Region parallelling the north Atlantic (IRD) ice events. The results showed that the change rhythm in the long time scale(from hundreds of years to thousands of years)and climate abruption appeared again and again, which is a wider range of phenomenon and reveals the instability of climate. There had occurred several important climatic abrupt events since the last deglaciation, such as B ~ A (Bølling ~ Allerød) warming period, YD event, “8.2 ka event” and “4.2 ka event”, the medieval warming period and the little ice age climate events. Obtaining the change intensity, process and time limit of these major events in the global major districts is crucial to further deduce the cause and incentive mechanism of the event occurrence. B ~ A event is a warm event, followed by the coldest YD event, which was recorded by the peat from Hani in Northeast,Dajiuhu in Shennognjia Basin and Dahu in South China. The most ancient peat sediments of Hongyuan region were discovered that these deposited from 13 ka BP that was close to the end time of B ~ A event. YD event had been clearly recorded by all the peat deposits of these four regions, but there were difference from its starting time and time range. The peat depositions of Dajiuhu and Hongyuan started later about 0.3 ka than that in Dahu and Hani, which might be relevant to their latitude and altitude. However, the further north the latitude was, the later the starting times of 8.2 ka event recorded by peat in China were, whereas the earliest starting time of 4.2 ka event appeared in Hani region, and the further north the latitude was, the earlier the end time came. Therefore, the two events in different regions showed that there were various time durations, which meant that they were controlled by diverse dynamic reasons or mechanisms.
Finally, we prospected the future of palaeoclimatic research on the peat records, and suggested that sequence comparision among  multiregional climate change should be expanded and reconstructed. Moreover, establishing a high-resolution peat archive recording  the palaeoclimatic and paleoenvironmental change for the northwest arid and semi-arid areas is significant  for  studying  evolution mechanisms, further response processes and mechanisms of peat to climate change in the region influenced by the west wind. To strengthen the theoretical research and make an  analysis of  the cause, evolutionary process and its mechanism in different peatland are very important. Only by understanding the characteristics  of peat deposition and development mechanism in the palaeoclimatic research recorded by peat, can the obtained environmental and climatic information be more and more reliable and persuasive. With deep understanding about the physical meaning of all climatic proxies and reconstruction of the reasonable and accurate relationship between proxies and environmental factors, the application of climate factors in the peatland is expected to make breakthroughs, which will promote the research of peatland in palaeoclimate. Improving and paying attention to the atmospheric settlement peat records, in accordance with chemical elements and the research methods of environmental magnetism, has  good prospect for the atmospheric environment tracer research. In particular, using the environmental magnetism means to elucidate magnetic properties of peat sediment, mechanisms of magnetic viability and whether the change of magnetic properties is responds  to the changing environment and climate should be carried on. The study of basic theory and carbon cycle mechanism of peat deposit is meaningful to research peatlands and global change. If we can carry out the peat ecological system mechanism study of the carbon cycle, to reduce the increase in greenhouse gas emissions rate and maintain ecological balance have an important meaning, what′s more, to slow current global climate change effectively has the substantial practical significance. 

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