SCIENTIA GEOGRAPHICA SINICA ›› 2015, Vol. 35 ›› Issue (10): 1318-1324.doi: 10.13249/j.cnki.sgs.2015.010.1318

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Grain-size Features of Lacustrine Sediments from Chaohu Lake and Its Sedimentary Implications

Li-qiang XU1(), Fang XU2, Tao-fa ZHOU1   

  1. 1. School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui 230009, China
    2. School of Medical Engineering, Hefei University of Technology, Hefei, Anhui 230009, China
  • Received:2014-03-16 Revised:2014-06-21 Online:2015-10-25 Published:2015-10-25

Abstract:

Lacustrine sediments are ideal natural archives for studying environmental changes in the past. A sediment core, namely CHX, was collected from the western Chaohu Lake, east of China and its grain-size features at the intervals of 2 cm were investigated in the present study. The changes of grain-size compositions throughout the profile CHX were reconstructed. Grain size parameters, including mean grain-size (Mz), standard deviation (Sd), skewness (Sk) and kurtosis (Ku) were calculated. It is found that those sediments are mainly composed of fine grained silt and clay. Mz, Sd, Sk and Ku and fractal dimension of the sediments suggest that those deposits were well to very well sorted, positive to very positive-skewed, very to extremely leptokurtic and also show evident fractal features. C-M pattern and probability cumulative curve of the sediments from core CHX unveiled an low-energy environment, and revealed that grains move in the major forms of saltation and suspension, which accounts for about 70% and 25%~30%, respectively. Principal component analysis (PCA) was applied to identify controlling factors for grain size features of sediments from the Chaohu Lake. From principal component analysis, it is identified that the first principal component (PC1) controls fine-grained clay content in the bulk sediments and further reflects the offshore distance of detritus in the lake. PC1 and mean grain-size Mz are thus robust markers for lake water level and local precipitation. These sediments can be further used to reconstruct regional precipitation history.

Key words: Chaohu Lake, sediments, grain size, fractal dimension, factor analysis

CLC Number: 

  • P532