Depositional Characteristics and Formation Mechanisms of Contour Current in South Dongsha Uplift during the Quaternary
-
摘要: 珠江口盆地东沙隆起南缘深水陆坡区（水深约900~2 600 m）是西北太平洋和南海水体交换的活跃区域，发育了类型丰富的等深流沉积体，但等深流沉积特征和成因机制尚不明确，相关研究仍缺乏足够证据。通过区域地震资料和ODP1144站钻井数据分析发现，该区第四系地层中可识别5种深水底流成因的等深流沉积：涂抹形漂积体、伸长形-丘形漂积体、限制形漂积体、沉积物波以及席状漂积体。根据等深流沉积特征、发育类型以及分布范围，从陆坡到深海平原大致依次出现涂抹形漂积体、伸长形-丘形漂积体、限制形漂积体和席状漂积体，而具有波状沉积底形的沉积物波主要发育于陆坡区。东沙隆起南缘第四系等深流沉积的形成、演化受控于多种因素，其中主控因素包括：西北太平洋与南海中-深层水体的"双层"环流结构、科里奥利力的"右偏"效应、冰期-间冰期海平面升降所诱导的底流与重力流交互作用机制以及新构造运动时期火山活动对海底地貌的改造。Abstract: The continent slope of the South Dongsha Uplift of the Pearl River Mouth Basin (water depth is between 900 m~2 600 m) with series of contourite developed exist prominent water exchange between South China Sea and Western North Pacific, but the researches on depositional characteristics and formation mechanisms of contourite are still lack of sufficient evidences. Based on the analysis of regional seismic data and drilling data from ODP1144 site, 5 types of bottom current deposition can be established:plastered drift、elongated-mounded drift、separated drift、sediment wave and sheeted drift. Through the characteristics and distribution of contour current, the contourite developed successively from continent slope to abyssal, and sediment wave mainly developed in continent slope. The development and evolution of contourite in South Dongsha Uplift during the Quaternary controlled by various factors, the main factors including:the "two-layers" circulation pattern of intermediate and deep-water masses between South China Sea and Western North Pacific、Coriolis effect、the interaction between bottom current and gravity current which induced by eustacy during glaciation and interglacial periods and the topography of seafloor which was modified by neotectonic movement.
-
Key words:
- Pearl River Mouth Basin /
- South Dongsha Uplift /
- Quaternary /
- bottom current /
- contour current
-
点击查看大图
计量
- 文章访问数: 455
- HTML全文浏览量: 23
- PDF下载量: 805
- 被引次数: 0
下载:
