The Study Of Climate Recorded Since Nearly1500aBP From A Peat Core Located In Northern Mountain Area Of Fujian Province

With the development of PAGES, the paleo-climatic and paleo-environmental reconstruction has become one of the most productive research projects. In this project, it is important to choose and study some geological records and climatic indicators. Peat deposition is normally formed in the Quaternary, especially in the Holocene. Since the formation of peat is mainly controlled by the climate condition, peat deposition contains a lot of the paleo-climatic and paleo-environmental information.Xianshan basin, an no fiver affluxes basin, locate in the eastern of section on the subtropical monsoon region Pingnan, in the southeast part of China. It is surrounded by low hills and supplied by atmospheric precipitation. With peat of the typical lake sediment, the Xianshan basin is extremely sensitive to the climatic change, and it is an ideal site for the research of regional climate in response to the global climatic change.In this paper, we do a research with the peat’s environment proxy index of Xianshan. According to chronology and environmental proxy index of pollen, degree of humification, TOC, TN and C/N, environmental changes sequence since nearly1500aBP in this region. Also, the chronological sequence of this core was established using6AMS14C dates, and according to the comprehensive analysis of the peat humification, combined with pollen records, TOC, TN, C/N for the profile, We reconstruct nearly1500years climate history of the study area, which can be divided three phases:Ⅰ:1423-1144aBP, equivalent to the warm stage of sui and tang dynasties, the pollen zone is Quercus, Castanopsis, Glyptostrobus assemblage, representing a tropical and subtropical forest environment in this area, peat humification, TOC, TN and C/N are higher, indicating a warm and wet climate;Ⅱ:1144-1750aBP, the pollen zone is Dicranopteris, Poaceae,Cyperaceae, Quercus, Pinus, Polypodiaceae assemblage, implying that the primarily regional vegetation composition characteristica are herbs and ferns, overall, the peat humification, TOC and TN are lower, indicating a relatively dry and cold conditions corresponding to the MWP, the signal of the peat recorder is not significant, however, The LIA has a significant performance;Ⅲ:about from200aBP to so far, the peat humification, TOC and TN are the highest of whole section, generally, has a increasing trend, indicating precipitation increased, which as warm and wet environment, the pollen zone is Pinus, Dicranopteris, Poaceae, Cyperaceae, Myriophyllum, Concentricystes assemblage, indicating the regional vegetation to coniferous forest and arbor is given priority to, should be tropical and subtropical forest vegetation.Also, using red noise spectrum analysis with the redfit3.8show that it exist aquasi-periodic with173a、41a、32a、22a、21a in changes of humification and C/N, which are in relation to climate of the monsoon region at low-latitude subtropical change on the secular solar activity response.