Holocene Paleoenvironment Reconstruction By Using Pollen And Phytolith Records In Hanni Peatland

Peatland has the characteristics of wide distribution, good continuity, high timeresolution, and rich climate information. Furthermore, the requirement for itsexistence is extremely strict, and it is also sensitive to environmental change, so itplays an important role in global change research. In this study, a3.5m peat profilewas study in Hani peatland, and by studying156phytolith samples and35pollensamples, the paleoenvironment since16ka b2k in Hani peatland was reconstructued.Considering the combine of phytolith data and pollen data, Principle ComponentAnalysis was used, and the combined indicator was found better than single ones. Themain conclusions of this study are as follows:1. The phytolith record of Hani peatland could reconstruct the paleoenvirionmentof Hani peatland efficiently, and provided comparable climate event with otherregions, it could be found that in Hani peat land, the climate forcing factor is not thesame between Last Glacial Termination and Holocene.2. Hani peatland recorded world wide climate events such as Younger Dryas andNorth Atlantic Ocean ice-rafted debris events.3. In Hani peatland, since16ka b2k, there were flunctuations of cold and warm,between16ka b2k and14.9ka b2k, it was a cold period, between14.9ka b2k and13ka b2k, it was a warmer period compared to the prior period, between13ka b2k and11.3ka b2k, it was the coldest period of the profile, between11.3ka b2k and6.8kab2k, it was the warmest period of the profile, between6.8ka b2k and1.0ka b2k, itwas a cooler period compared to the prior period.4. The humidity of Hani peatland has similar changing trend with temperature inlarge scale, but not exactly the same pace. During16~8.6ka b2k and5.9~2.7ka b2k,humidity rose or fell with temperature rose or fell, during8.6~5.9ka b2k and2.7~1kab2k, humidity fell while temperature rose.5. Herbs in Hani peatland mainly include species from Cyperaceae, Artemisia,Pooideae, Oryzoideae and Panicoideae, woods in Hani peatland mainly includespecies from Abies, Picea, Quercus, Juglans, Ulmus and Betula, species from Pinusmight grow later. In Hani peatland, the forcing factor of the ratio of woods and herbscould be temperature, but during2.7~1.0ka b2k, because of the low humidity,although the temperature became warmer, the ratio of woods and herbs showed a lagof phase to temperature, and species from Pinus was considered a fast growth in thisperiod. 6. In this study, the combined indicator using PCA seem to have more advantagethan single indicator, and could reconstruct the paleoenvrionment more precisely.