| Peat mainly developed from the accumulation of plant residue decomposition after vegetation in situ death. It is a kind of good geological archives to obtain the information of regional past environment change in high resolution.The Zoige plateau in the northeast qinghai-tibet plateau is the biggest peat resource distribution area in China, which is very sensitive to climate change.We digged in and obtained a peat profile near Huahu lake in the Zoige plateau,and then use the dating technique of natural and artificial radionuclides 210 Pb and 137 Cs to establish the high precision chronological sequence of this sedimentary sections.On this basis, the determination of the basic physical and chemical properties,including the dry density, water content, organic carbon content data and so on, were used tocharacterize the structure of sedimentary section and study therecent peat sediment accumulation rate, as well as the organic carbon deposition rate.Peat deposition and organic carbon accumulation as well as its response to climate change are analyzed by the reconstruction of climate change from proxies, including particle size, the degree of humification and observation and simulation of meteorological data.Through the analysis of black carbon, susceptibility, the content of heavy metals and organic contaminants, environmental pollution history of the zoige plateau area is concluded, thus to explore the region record of the transition of Holocene epoch to the Anthropocene.The main results and conclusions are:First, using the constant supply rate(CRS) model of210 Pb radioactive dating technique established the high precision framework of 30 cm peat profile.It is concluded that the peat sediment accumulation rate is 0.16 cm yr-1 and the sedimentation flux is 0.095 g cm-2 yr-1 between 1824-2011 a.Second, according to the dry density and the organic carbon content and other physical and chemical indicators, calculate the organic carbon deposition rate of peat profile, namelythe recent rate of carbon accumulation(RERCA) is86.12 g C m-2 yr-1, the carbon stock of Huahu lake peatland in the last more than one hundred years of is 16.10 kg C m- 2.Third, through the observation data by meteorological stations, satellite observations and reconstruction of climate data obtained by proxy, we found that there is a relatively small increase of temperature, at the same time, there is significant fluctuations in precipitation changes, and the rate of carbon accumulation in line with the change of precipitation, indicating that the main factors affecting the accumulation of carbon is precipitation.Fourth,based on the research of black carbon,magnetic susceptibility, heavy metal elements and PAHs which are related to human activities and industrial development, the change of environmental pollution of the zoige area in the past nearly 200 years is inversed, indicating the influence of modern human activities on the natural environment.According to the pollution history and literature of the development and changes in the zoige area, we concluded that the transformation of the holocene into the anthropocene happened in the first industrial revolution period in zoige area, which is in accordance with the starting point of the anthropocene put forward by Crutzen etc.The study reveals the peat sedimentary characteristics, modern carbon accumulation rate, the influence of climate change on carbon accumulation, the history of environmental pollution of the region as well as of the transition of the holocene epoch to the anthropocene near Huahu Lake in the past nearly two hundred years. To a certain extent, this study not only is an improvement and supplement to the research of peat deposition in the northeast of Qinghai-Tibet plateau, but also has scientific guiding significance to the human and production activities, scientific development and ecological civilization construction.Furthermore, China’s Anthropocene issues were preliminary discussed. |
PDF Full Text Request