| 摘要: |
| 琼州海峡东口潮流沙脊主要受到东西向往复流和地形地貌的控制，是我国重要的海砂资源地。通过对琼州海峡东口海域350个站位的表层样粒度数据的分析，探讨了研究区的沉积物粒度特征，并划分了沉积环境。结果显示，研究区底质类型共17种，以砂、砾质砂、砾质泥质砂、泥质砂质砾、砂质粉砂为主，其中潮流沙脊区，主要分布有砂、砾质砂和砾质泥质砂，以东则分布有砂质粉砂和粉砂质砂，砂质砾和泥质砂质砾多分布于冲刷槽内。研究区沉积物砾、砂、粉砂、粘土的平均占比分别为9.7%、71.0%、15.3%、4.0%，平均粒径为2.15 φ，分选系数为1.69，其中潮流沙脊区砂占比多超过95.0%，平均粒径多小于2.00 φ，分选较好，随着水动力的减弱，由西向东，沉积物逐渐变细。通过聚类分析，研究区共划分出6类沉积区，Ⅰ类、Ⅱ类沉积区分别代表潮流沙脊区和冲刷海槽区，Ⅲ类代表海湾环境，Ⅳ类代表潮流沙脊前缘，Ⅴ类代表开阔陆架，Ⅵ类代表河口水下三角洲沉积环境。 |
| 关键词: 海洋地质学 潮流沙脊 表层沉积物 沉积环境 琼州海峡东口 |
| DOI：10.3969/J.ISSN.2095-4972.2022.04.008 |
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| 基金项目:2019年海南省基础与应用基础研究计划（自然科学领域）高层次人才项目资助项目（2019RC349）;2022年海南省自然科学基金资助项目（422RC800）;海南省国土资源厅资助项目（HZ2015-235）;海南省地质局资助项目（T102972.510）;南方海洋科学与工程广东省实验室（珠海）创新团队建设项目资助项目（311020003） |
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| Surface sediment characteristics and sedimentary environment division of tidal sand ridge at the east entrance of Qiongzhou Strait |
| TONG Changliang,WANG Huaqiang,QIN Maogang,WANG Aijun |
| (Hainan Key Laboratory of Marine Geology Resources and Environment， Haikou 570206， China;Hainan Geology Detection and Research Centre， Haikou 570206， China;Marine Geological Institute of Hainan Province， Haikou 570206， China;Guangzhou Hydrographic Center of the Navigation Guarantee Center for South China Sea, MOT， Guangzhou 510320， China;Third Institute of Oceanography, MNR, Xiamen 361005， China;Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082， China) |
| Abstract: |
| The tidal sand ridges at the east entrance of the Qiongzhou Strait controlled by the eastwest reciprocating current and the landform are an important resource area of sea sand in China. Based on grain size analysis of 350 seafloor samples at the east entrance of Qiongzhou Strait, the grain size characteristics of sediments in the study area are discussed and the sedimentary environment was classified. There are 17 sediment types in the study area, which are mainly sand, gravelly sand, gravelly muddy sand, muddy sandy gravel and sandy silt. Among them, sand, gravelly sand and gravelly muddy sand mainly distribute in tidal sand ridge area, where sandy silt and silty sand distribute to the east, and sandy gravel and muddy sandy gravel distribute mostly in the shallow channel. The average contents of sediment gravel, sand, silt and clay in the study area are 9.7%, 71.0%, 15.3% and 4.0%, respectively, with an average particle size of 2.15 φ and a sorting coefficient of 1.69. The sediments contain more than 95.0% sand with average particle size of less than 2.00φ, which shows good sorting. With the weakening of hydrodynamic force, the sediments gradually become finer from west to east in the study area. According to the cluster analysis, the study area can be divided into 6 types, which represent tidal sand ridges, shallow channel, bay environment, tidal sand ridge front, open continental shelf and submerged estuarine delta sedimentary environment from typeⅠto VI, respectively. |
| Key words: marine geology tidal sand ridge surface sediments sedimentary environment east entrance of Qiongzhou Strait |
