大连复州湾底质沉积物粒度特征与沉积环境分析

Grain size characteristics of surface sediments and the response to sedimentaryenvironment in Fuzhou Bay,Dalian

对辽东半岛西部复州湾海域底质沉积物样品进行粒度分析结果表明,其粒度特征有较大差异：样品平均粒径值为1.2～6.5Φ；分选系数为1.4～2.6,分选为较差-差；偏度特征表现为极正偏和极负偏并存.粒度的空间分布存在一定分异规律,由湾内至湾外粒径表现出粗-细-粗的变化特征.粒度变化是对该区域物质输运和地形变化的响应,借助Weibull分布,推断河流携带物质可以被推送至5 m等深线外堆积,5～10 m等深线间沉积物表现为细粒的浅海台地沉积,10 m等深线以外沉积物受河流的影响微弱.矿物学证据也表明,河流输运对湾内沉积物贡献有限,仅限于5 m等深线以内的水下三角洲,湾内沉积物主要来自于辽东湾沿岸冲刷和湾内基岩的剥蚀.

Marine surface sediments from the Fuzhou Bay,the western Liaodong Peninsula,were obtained for sedimentary analysis.The characteristics of grain size are corresponding to the sedimentary environment.The grain size parameters show a significant difference among samples from various positions,as the average grain sizes range from 1.2Φ to 6.5Φ.The grain sizes are all poor sorted （1.4～2.6） with fine to coarse skewness,and display a spatial change as fine to coarse to fine from the estuary to the shallow sea.The 5 m and 10 m isobaths mark the edge of these boundaries,probably resulting from sediment transport and submarine topography.Most of river sediments can be transported to the 5 m isobath,and sediments in the area between 5 m to 10 m isobaths are mainly from river and outer sea,while little river sediments can get to west of 10 m isobaths.With the evidence of both Weibull function and mineralogy,most of the sediments in Fuzhou Bay are from the erosion of Liaodong Bay and Fuzhou Bay.