摘要
海底峡谷是海底长条形且窄而深的负地形,在主动和被动大陆边缘以及岛弧附近都有出现。澎湖海底峡谷群具有坡度大、地貌复杂的特点。运用高分辨二维单道地震资料,解释了峡谷的下切侵蚀面。分析表明,澎湖海底峡谷在剖面上表现为"V"型、"U"型或者底部宽缓的"U"型下凹状地震反射。峡谷上游受到的侵蚀作用较强,谷底次级沟槽发育,坡面冲沟发育,峡谷内部未见现代沉积物充填。澎湖海底峡谷群的形成与第四纪晚期海平面的变化有关,低水位时期,陆架大片出露,大量碎屑物质可以直达陆架边缘甚至上陆坡,此时重力流活跃,不断切割地层,逐步形成了澎湖海底峡谷群。
Submarine canyons, a kind of elongated, narrow and deep negative reliefs, are common at active or passive continental margins. The Penghu submarine canyons are characterized by large slope and complex landform. High resolution single-channel 2-D seismic data are used in this paper to identify submarine canyons. Data shows that the canyons are generally in＂ V＂ shape or＂ U＂ shape, or ＂U＂ shape with a wide bottom in seismic profiles. Strong erosional features are commonly observed in the upper reaches of the canyons. There secondary grooves and slope gullies without sediment infilling are quite common. The formation of the Penghu submarine canyons is related to the sea level change during the late Quaternary. In the low water stage, the shelf was widely exposed to air and deposition occurred only in the area out of the shelf or even on the upper slope. Active gravity flow contributed to the formation of the submarine canyons.
作者
聂鑫
罗伟东
周娇
NIE Xin LUO Weidong ZHOU Jiao(Key Laboratory of Marine Mineral Resources, Ministry of Land and Resources, Guangzhou 510075, China Guangzhou Marine Geological Survey, China Geological Survey, Guangzhou 510075, China)
出处
《海洋地质前沿》
CSCD
2017年第8期18-23,共6页
Marine Geology Frontiers
基金
国土资源部海底矿产资源重点实验室项目(KLMMR-2014-A-13)
中国地质调查局项目(1212011220115)
关键词
澎湖海底峡谷
沉积物波
重力流
滑塌
Penghu submarine canyons
sediment waves
gravity flow
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