北部湾海岸现代风沙与海滩沙粒度特征对比

A comparative analysis of grain size characteristics of modern aeolian sand and beach sand from the coast of Beibu Gulf in China

对分布在北部湾海岸——广西北海、钦州、防城港与海南西部棋子湾的88个现代风沙和95个海滩沙样品进行了粒度分析与对比。结果表明:北部湾海岸风沙与海滩沙均以细沙、中沙为主,二者在风沙中的平均含量分别为68.55%和28.61%,在海滩沙中则分别为50.57%和40.11%;海岸风沙和海滩沙的平均粒径分别为2.26Φ和2.11Φ,分选系数分别为0.48Φ和0.62Φ,偏度分别为0.00和0.04,峰态分别为0.96和1.21,海岸风沙比海滩沙略细、分选更好、偏度趋于对称、峰态趋于中等;二者粒度概率累积曲线均以跃移组分为主,海滩沙中含少量推移和悬移组分。海滩沙与风沙的粒度特征还呈现明显的区域性差异,底质以中沙为主的北海、棋子湾海滩沙与其上发育的风沙在粒度结构参数散点图上区分度更高。

Based the comparative analysis of grain size properties of 88 modern aeolian sand samples and 95 beach sand samples from Beihai,Qinzhou,Fangchenggang in Guangxi and Qiziwan in western Hainan along the Beibu Gulf,it suggests that both coast aeolian sand and beach sand mainly consist of fine sand and medium sand,and their average contents account for 68. 55% and 28. 61% in aeolian sand,and 50. 57% and 40. 11% in beach sand,respectively. In terms of grain size parameter,the mean grain size of coastal aeolian sand and beach sand is 2. 26 Φ and 2. 11 Φ,the sorting coefficient is 0. 48 Φ and 0. 62 Φ,the skewness is 0. 00 and 0. 04,and the kurtosis is 0. 96 and 1. 21,respectively. Compared with the beach sand,the aeolian sand is slightly finer,sorted better,skewness tends to be symmetrical,and kurtosis tends to be moderate. Both grain size probability cumulative curves are dominated by the jumping component,and the beach sand contains a small amount of moving and suspended components. The grain size characteristics of beach sand and aeolian sand also display obvious regional differences. The scatter of grain size structure parameter is distinguishable between the beach sand in Beihai and Qiziwan that is mainly the medium sand,and its overlying developed coastal aeolian sand.