COMPARATIVE STUDY OF SEDIMENT GRAIN-SIZE FEATURES OF THE QIQU ISLANDS

Comparison of grain-size features of surficial sediments between the Qiqu Islands area and other areas is made with the data from published papers. The higher sorting is often found in the sediments with mean grain size of 0.1~0.2 mm, while the fine sediments are often badly sorted. Positive skewness is often in company with sediments whose mean grain sizes are between 4.5Φ~7.5Φ, and the coarser the sediments, the more positive the skewness. The skewness of the sediments coarser than 4Φ shows no distinctly negative or positive tendency. Sediments in median grain size of 4Φ~5Φ are are less common in the Qiqu Islands area, perhaps because the sediments are between suspension and saltation loads. The deficiency of the components may be the reason to cause the positive skewness of the sediments finer than 4Φ.