Submarine channel evolution: active channels in fjords, British Columbia, Canada
Submarine channel evolution: active channels in fjords, British Columbia, Canada
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海底航道的演变：加拿大不列颠哥伦比亚省峡湾中的活跃航道
DOI：
10.1007/s00367-012-0280-4
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发表时间：
2012
影响因子：
2.1
通讯作者：
B. Bornhold
中科院分区：
文献类型：
--
作者：
K. Conway;J. Barrie;K. Picard;B. Bornhold
不列颠哥伦比亚省（加拿大）的几个峡湾，包括奈特、布特和多巴湾，海底水道系统十分发达。在三角洲前缘的峡湾头的情节故障的渠道是浊流的活跃导管。最近获得的条带多波束测深数据，使这些渠道系统的形式进行了全面和详细的评估。在布特和多巴入口（2008年3月和2010年11月）重复进行的多波束调查表明，深切的渠道可能会在短至2.5年的时间内经历加积或侵蚀。在水道系统中记录了局部显著（>15米）的水深变化，沿着约有超过5米的水深差异。20-25%的复测通道长度。在多巴入口观察到的涉及上三角洲前缘的斜坡破坏是新通道段快速形成的机制。在一些河道弯曲内侧的沉积物加积表明，随着河道侧向迁移的进行，可能会形成点坝。在某些外部河道弯道处发现了河道侧壁滑塌，这些部位可能出现堆积沉积。横向迁移伴随着外部弯曲侵蚀、河道整体加深和阶地发育。
Seafloor channel systems are well developed in several British Columbia (Canada) fjords, including Knight, Bute and Toba inlets. The channels are active conduits for turbidity currents during episodic failures of delta fronts at the fjord heads. Recently acquired swath multibeam bathymetric data enabled a complete and detailed assessment of the form of these channel systems. Repeated multibeam surveys in Bute and Toba inlets (Mar. 2008 and Nov. 2010) indicate that the deeply incised channels may undergo accretion or erosion over a period as short as 2.5 years. Locally significant (>15 m) bathymetric changes were documented in the channel systems, with bathymetric differences exceeding 5 m occurring along approx. 20–25% of the resurveyed channel lengths. Slope failure involving the upper delta front observed in Toba Inlet is a mechanism for the rapid initiation of new channel segments. Sediment accretion on the inner side of some channel bends indicates that point bars may form as lateral channel migration proceeds. Channel sidewall slumps are found at some outer channel bends and mounded deposits may occur at these sites. Lateral migration is accompanied by outer bend erosion, overall deepening of the channel and the development of terraces.