Hill Philip R, Conway Kim, Lintern D Gwyn, Meulé Samuel, Picard Kim, Barrie J Vaughn
Natural Resources Canada, Geological Survey of Canada, Box 6000, Sidney, British Columbia, Canada V8L 4B2.
Mar Environ Res. 2008 Dec;66 Suppl:S39-48. doi: 10.1016/j.marenvres.2008.09.003. Epub 2008 Oct 8.
This paper presents a review of sediment dispersal processes in the Strait of Georgia, based on marine geological studies. Sediment from the Fraser River is dispersed around the Strait through a variety of transport pathways. Most sand and coarser silt fractions settle out and are deposited within a few 100 m of the channel mouths. Both channelled and non-channelled gravity flows probably transport sediment downslope and onto the basin floor. Asymmetric tidal currents force a predominantly northward sediment drift, resulting in a reworked slope off Roberts Bank and a finer-grained depositional slope off Sturgeon Bank. Far-field sediment accumulation is controlled by local morphology and sediment dynamics. Multibeam mapping and seismic profiling reveal that some parts of the basin floor are characterized by bottom sediment reworking and erosion. Given the complexities of sediment dispersal and seafloor reworking, generalizations about sediment dispersal paths and sedimentation rates are difficult. Future understanding will be advanced by the cabled observatory, VENUS, which will enable near real-time monitoring of key processes.
本文基于海洋地质研究，对佐治亚海峡的沉积物扩散过程进行了综述。弗雷泽河的沉积物通过多种输送路径在海峡周围扩散。大部分沙子和较粗的粉砂级颗粒沉降下来，沉积在河口口外几百米的范围内。有槽和无槽重力流可能都将沉积物向下坡输送到盆地底部。不对称潮流导致沉积物主要向北漂移，使得罗伯茨浅滩外的斜坡受到重塑，鲟鱼浅滩外形成了粒度更细的沉积斜坡。远场沉积物堆积受局部地形和沉积物动力学控制。多波束测绘和地震剖面显示，盆地底部的一些区域以底部沉积物的重塑和侵蚀为特征。鉴于沉积物扩散和海底重塑的复杂性，很难对沉积物扩散路径和沉积速率进行概括。未来，通过“金星”海底观测站将推动相关认识的进步，该观测站将能够对关键过程进行近实时监测。
