The Record About Carbon And Its Significance In The Sediments Of Hangbu River Valley In AnHui Province

As the information database of climatic and environmental changes, lake sediment provides high-resolution climatic change information which at the scale of century or even decade. Chaohu Lake is in the mid-downstream area of the Yangtze River, in eastern monsoon climate, it is particularly sensitive to the change of the environment. This thesis regarded Hangbu river valley which is relatively close basin in the monsoon environment as the research object,layout and gathered ACN, AC4 , AC3 and ALE core samples and samples in three small branches basin after collecting relevant materials and making an on-the-spot investigation in this region. We have carried on organic carbon content , total nitrogen content , organic carbon stable isotope,organic nitrogen stable isotope, carbonate content, granularity and determination of time and other experimental analysis. Drew environmental information from several deposit core, analyze the influence factor of the distribution about organic carbon , organic carbon stable isotope change in Hang Bu river valley,and the environmental meaning in its instruction with other environmental indexes has carried on the discussion.It shows that the organic δ ¹³C value in the ACN core mainly was reflected by the input of C3 vegetation primarily in land,the region environmental variation which carry influence isotope fractionation. Looked from the whple change, the higher δ ¹³C value instructs the warm climate ,the negative organic δ ¹³C value should instruct the climate changes of cold tendency,its value change show the acute reflection of environmental variation. The organic carbon content change is incompletely consistent with the organic δ ¹³C change, its height cannot instruct the climate changes in temperature change completely. In the lake deposition stage, δ ¹⁵N has the uniformity with δ ¹³C change,the smaller δ ¹⁵N shows climate change colder,the higher δ ¹⁵N return to the warmer weather. Since center the brand-new world the basin natural environment change has been possible to divide into the following several development phase: (1) 6.9⁴.3kaBP,organic δ ¹³C relatively higher approximately, but has gradually become negative tendency, the climate is warm, and show change tendency of cooler . The 6.0⁵.2kaBP time is a climate undulation : 6.0⁵.9kaBP,5.6kaBP and 4.3kaBP, δ ¹³C value obviously negative, instructed the climate changes the cold event; it is an elevation of warm change in 5.4kaBP. (2) 4.3².2ka BP, δ ¹³C value relative negative, but r slowly, δ ¹⁵N also became bigger...