Pollen Assemblages And Paleoenvironment Change Since Holocene In Ba Shang

Spore-pollen is an effective indicator for paleoenvironmental and paleoclimatic research. The reliable relational model of surface soil pollen assemble and climatic parameters is the basis for quantitative reconstruction of past climate variability. Using the interpolation method to get the meteorological dates(temperature and precipitation dates)in sampling sites based on the regional climatic data set is the key to establish the model.Therefore, this study firstly studied the meteorological data interpolation method in Bashang. The results show that Co-kriging is the best method for the interpolation of temperature precipitation data.Then According to the latitude and longitude, the interpolation results directly assigned to surface pollen, pollen and climate model establishment, we can establish the pollen precipitation and temperature model. Combined with the 344 cm profile in the lake of ChaHannaoer, including pollen samples, size samples and reliable 6 dating sample, We through the comprehensive analysis. Finally Bashang of paleoclimate evolution since the Holocene was quantitative reconstruction.The main analysis of the time is Holocene, the other part merge into a group. In 11.73 ka B.P.~45.66 ka B.P. phase, the average temperature of 4.80?, average rainfall of 344.96 mm. In 7.68 ka B.P.~11.73 ka B.P. phase, The annual average temperature and annual average rainfall rose slightly. In 6.04 ka B.P. ~ 7.68 ka B.P. phase, the average temperature of 4.84 ?, the average rainfall of 347.81 mm. In 4.12 ka B.P.~6.04 ka B.P. phase, The annual average temperature increased slightly. In 3.81 ka B.P. ~ 4.16 ka B.P.phase, the average temperature and average rainfall continued to rise. In 3.54 ka B.P.~3.81 ka B.P. phase,the average temperature reached the highest,and the average rainfall was the maximum value.the average temperature of 5.08?, average rainfall of 354.28 mm.Thereafter in 2.80 ka B.P.~3.54 ka B.P. the average temperature and average rainfall all had a downward trend.In 2.21 ka B.P.~2.73 ka B.P. phase, the annual average temperature and annual average rainfall rose sustained. Since 2.21 ka B.P. the average temperature of 4.79 ?, average rainfall of 348.15 mm.On the whole, the quantitative reconstruction of Bashang region since the Holocene climate change suggests that in Bashang region the Holocene climate change and the classic Holocene climate change is almost the same changes This is the overall performance of the early Holocene, the temperature rise and precipitation increasing,and in the middle of the Holocene, the temperature is the highest and precipitation is the most. And since the late Holocene, the climate of this area has changed the trend of decreasing the temperature again.It is roughly equal to the surrounding research levels since Holocene,and it has its own peculiar climatic characteristics.Result of this study is helped to understand typical climatic characteristics of this region, especially the farming-pastoral zone in North China, and then provides basic data and theoretical basis for the development of environmental policies.