摘要
本文基于多波束测深和高分辨率多道反射地震数据研究了东沙海域深水巨型水下沙丘的特征.巨型水下沙丘发育在230~830m水深的上陆坡范围内,呈斑块状分布.NW-SE向的近海底流体运动不仅冲蚀地层,形成了三条与水下沙丘间隔分布的冲蚀带,为水下沙丘提供了沉积物来源,同时也为水下沙丘的形成提供了动力源.研究区水下沙丘波长(L)范围55~510m,波高(h)范围1.5~20m,二者呈指数关系分布.沙丘的波长随水深增大而增大,波高则在500~700m水深范围内最大.水下沙丘NE—SW向展布的脊线和几何参数关系是与现今水动力条件相平衡的结果.
Analysis of multi-beam bathymetric and high-resolution multi-channel seismic data acquired by the Guangzhou Marine Geological Survey reveals the presence of deep-water very large subaqueous sand dunes in the Dongsha region of the northern South China Sea. These subaqueous sand dunes are distributed as patches on the upper continental slope at depths of 230~830 m below water. It is suggested that their formations and migrations are influenced by a NW-SE toward near-seabed flow for supplying sediments and energies to maintain sand dunes. The flow scours the seafloor, generating three erosion strips which are separated by subaqueous sand dune zones. A highly correlated exponential relationship is defined by sand dunes geometric parameters in the Dongsha region, with a trough-to-trough wavelength range of 55~510 m and wave heights of 1.5~20 m. Sand dune wavelengths increase with growing seawater depth, but the larger wave heights are found at water depths of 500~700 m. It is the current hydrodynamic conditions that bring up both geometric parameters relationships and sand dunes＇ NE-SW trending ridges.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2017年第2期628-638,共11页
Chinese Journal of Geophysics
基金
国家自然科学基金(41576047
41506054)和国家自然科学基金重大计划重点项目(91128205)资助
关键词
东沙海域
深水巨型水下沙丘
水流冲蚀条带
水下沙丘几何参数关系
多波束
Dongsha region
Deep-water very large subaqueous sand dunes
Erosion strips
Geometric parameters relationships of sand dunes
Multi-beam sounding
