Different origins of seafloor undulations in a submarine canyon system, northern South China Sea, based on their seismic character and relative location

Abstract

Shiguo 2019. Different origins of seafloor undulations in a submarine canyon system, northern South China Sea, based on their seismic character and relative location. Marine Geology 413 , pp.

Bedforms on the submarine flanks of insular volcanoes: New insights gained from high resolution seafloor surveys

“…The interpretation of large‐scale bedforms is often more complex, especially if only bathymetric data are available. The main diagnostic criterion for discriminating their origin is the analysis of their internal geometry using seismic profiles, similar to what was proposed for large‐scale bedforms in non‐volcanic settings (Lee et al ., 2002; Li et al ., 2019). For instance, the seismic profiles crossing the MC1 field at Maucaley volcano (Fig.…”

Nepheloid Layer Structure and Variability Along the Highly Energetic Continental Margin of the Northern South China Sea

“…The upper slope has an angle of inclination ranging from 1° to 3°, while the lower slope has an angle of inclination ranging from 2° to 4° (J. Liu et al., 2019). The topography of the northern margin of the South China Sea is composed of several major canyon systems, including Kaoping Canyon, Penghu Canyon, South Taiwan Bank Canyon, Dongsha Canyon, Shenhu Canyon, and Pearl River Mouth Canyon, as well as two gentle slopes, namely Dongsha Slope and Jianfeng Slope (H. Chen et al., 2019; J. Li et al., 2019). The submarine canyon system in the northern margin of the South China Sea serves as the primary channel for the transportation of sediment from the continental shelf to the deep‐sea basin.…”

“…Continental margins are significant and intricate regions that connect shelf seas and the deep ocean. They are often characterized by large submarine canyons that cut across the continental margin with tortuous paths (J. Li et al., 2019; Nash et al., 2007; X. Wang et al., 2022). Furthermore, continental margins often experience strong nonlinear internal waves (NLIWs) (L. Chen et al., 2019; Huang et al., 2022; Ramp et al., 2022).…”

Progress and Prospect of Seafloor Instability Research

“…沉积物输送到深海 [64] ，重新塑造海床并影响后续的 沉积过程，发育广泛的漂积体沉积，可见明显侵蚀 特征，进而控制深水环境中砂粒的分布。因此，海 底滑坡及其诱发的密度流是将泥沙从陆坡运往深海 的重要过程。 高分辨率的地球物理数据是识别海底滑坡的主 要手段。海底滑坡在地震剖面上一般表现为杂乱至 透明的地震相，表明滑塌沉积物混合均匀，具有典 型的碎屑流地震反射特征 [66,67] 。一般将海底滑坡划 分为头部物源区、体部滑移区和趾部挤压区，在不 同部位表现出拉张或挤压的构造特征。由于海洋环 境错综复杂，海底滑坡的成因机制与陆上滑坡存 在众多差异，海底滑坡发育的内在条件有沉积物的 类型、沉积物的饱和度、地形条件(坡度)和软弱 层等 [68] 。除此之外，还有一些触发因素可能会降低 海底陆坡的稳定性，如地震活动、高沉积速率、火 山喷发、削峭作用、侵蚀、差异压实、泥底辟、火 山隆升、人类活动、流体活动、超孔隙压力、天然 气水合物分解、气体泄露和海平面变化等 [69] 。 海底滑坡主要存在两种滑移形式，即旋转式滑 坡和板片式滑坡(见图 2) ，前者通常伴随海底陆坡 的滑塌过程，后者则与地层内部的沿层滑动面息息 相关 [70,71] 。世界上最大的 Storrega 海底滑坡的发育坡 度约为 0.7°，但滑坡体波及范围超过 95 000 km 2 。 已有研究 [64,71] 在西非的 Agadir 和 Sahara 大型海底滑 坡中均识别出了多期次的沿层滑动面，并表现出阶 表 2 海底蠕变的全球分布、地形地貌特征与内部地质结构 海域 土耳其马尔马拉海 [48] 里海 [50] 地中海 [51] 法国阿基坦陆缘 [52] 加拿大波弗特海 [53] 韩国东海 [54] 南海东南部 [55] 南海神狐海域 [49,56] 南海东沙海域 [45] 地形地貌特征与内部地质结构 沟槽近平行于等深线，隆起侧翼坡度可达 40°，其高度随水深增加而增大 经济发展造成巨大危害 [73] 。例如，在加拿大海域 Grand Banks 的海底滑坡(1929 年) [74] 、印度尼西亚…”