| 摘要: |
| 利用1992年以来采自南黄海的沉积物样品和1996年的南黄海水文调查资料，采用地层对比、沉积动力及环境分析等方法，研究了济州岛西北海域反气旋型涡旋流型的环流性质、其下方泥质沉积物的特征以及它们之间的因果关系，并与南黄海中部的气旋型涡旋沉积进行了深入的对比。结果表明，反气旋和气旋型沉积物都是细粒的泥质沉积，是在沉积动力较弱的低能环境下生成的，但它们之间还存在明显的差异，特别是反气旋型涡旋的沉积厚度大、粒度较粗，进一步反映了两者沉积动力的差别，显示了气旋型涡旋和反气旋型涡旋是具有独立属性的两种低能环境。 |
| 关键词: 反气旋型涡旋沉积 下降流 沉积环境 济州岛西北海域 |
| DOI：10.11693/hyhz200002015015 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目，49894170、49776296号 |
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| AN ANTICYCLONIC EDDY SEDIMENT PATTERN IN NORTHWEST OF CHEJUS ISLAND |
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SHEN Shun-xi, YU Hong-jun, ZHANG Fa-gao
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Institute of Oceanology, The Chinese Academy of Sciences, Qingdao, 266071
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| Abstract: |
| To the northwest of Cheju Island there is an anticyclonic eddy type below a mud patch. Using sediment samples collected since 1992 and oceanographic investigation data in 1996, studies to understand the sedimentary environment of the mud patch including analyses of grain-size composition, mineral content and stratum chronology, and with comparison to the cyclonic eddy sediments in the center part of the South Yellow Sea were made. The results show that the mud patch can be classified into upper and lower stratum units at about 13.5m depth below the seabed, the lower sediment is composed of hard homogeneous dark greenish-gray mud with a lower water content (38.5%), and has an acoustic internal reflection and eroded surface. The upper sediment is composed entirely of soft dark-gray homogeneous mud with relatively higher water content (50.3%). Besides, in comparison with the cyclonic eddy sediments in the center part of the South Yellow Sea, it is found that there are differences in the sedimentary grain size and accumulation thickness from each other. This suggests that the upper mud sediment would be considered as the anticyclonic eddy sediment, while the lower layer sediment the eroded mud deposit.
This findings were as follows. 1) The vertical circulation of anticyclonic eddy type in the area northwest of Cheju Island has a double-eddy structure, i.e., the upper layer eddy is clockwise and more intense, with downwelling in the center, and the lower layer eddy is anticlockwise and weaker, with upwelling in the center. 2) According to their intrinsic properties, the mud sediments in the area, northwest of Cheju Island, can be classified into anticyclonic eddy sediment and eroded mud deposit. 3) An anticyclonic eddy sediment is thicker and is of larger grain size than that of the cyclonic eddy sediment in the center part of the South Yellow Sea, this suggests that there would have some differences in sediment dynamics between an anticyclonic eddy and a cyclonic one. |
| Key words: An anticyclonic eddy sediment, Downwelling, Sedimentary environments, The area northwest of Cheju Island |
