Geochemical Characteristics And Provenance Analysis Of East Dongting Lake

In this thesis,the element geochemistry of the samples taken from the sediments of the East Dongting Lake in summer and winter was measured,and the geochemical characteristics of the sediments in East Dongting Lake were analyzed.The main purpose was to clarify the elemental composition characteristics of sediments in the East Dongting Lake,to reveal the provenance of the sediments in the East Dongting Lake,and to analyze the chemical weathering degrees,sedimentary sorting of the sediments in East Dongting Lake.The results show that:1.The major element content in summer and winter of the East Dongting Lake sediment have change little,and the major elements compositon are closer to the upper and middle reachers of the Yangtze Rvier,and are quite different from the Xiangjiang River and the Lishui River.The trace element content did not change much in winter and summer as a whole,but some trace element content have season change a lot such as Ba?V?Ni?Co?Rb,Ba has higher winter content than summer because of biological factors,V,Ni,Co are adsorbed by colloidal substances,making winter content higher than summer,the solubility of Rb makes its summer content higher than winter.2.The Q-type cluster analysis of sediment samples from the East Dongting Lake shows that the samples come from the same provenance.The provenance rocks of the East Dongting Lake sediments have granite characteristics and originate from the upper crust,and are affected by the combined effect of the continental quartz provenance area and the acid volcanic provenance area,the rocks types are mainly granites.The main provenance area of the East Dongting Lake sediments is the middle reaches of the Dadu River in the upper reaches of the Yangtze River,and is also affected by the provenance of the middle reaches of the Yangtze River.3.The chemical weathering intensity of the East Dongting Lake sediments is medium-low and is related to the climate and hydrological conditions in the upper reaches of the Yangtze River where the provenance rocks are located.The hydrodynamic separation of the East Dongting Lake sediments is lower than that of the Yangtze River and the Yellow River.The reason is that the Dongting Lake is a lake with storage function,and its hydrodynamic conditions are weaker than other rivers.