| 台湾东部海域沉积物波特征及其成因探讨 |
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| 引用本文： | 刘杰,孙美静,高红芳,李学杰. 台湾东部海域沉积物波特征及其成因探讨[J]. 沉积学报, 2019, 37(1): 155-162. DOI: 10.14027/j.issn.1000-0550.2018.106 |
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| 作者姓名： | 刘杰 孙美静 高红芳 李学杰 |
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| 作者单位： | 中国科学院广州能源研究所,中国科学院天然气水合物重点实验室,广州 510640;国土资源部海底矿产资源重点实验室,广州海洋地质调查局,广州 510075 |
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| 基金项目： | 国土资源部海底矿产资源重点实验室开放基金资助项目（KLMMR-2015-A-11）；中国地质调查局项目（DD20160138，DD20160140，GZH201300502）；广州市珠江科技新星（201710010198） |
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| 摘 要： | 利用地震剖面对沉积物波的分布、形态和内部结构进行了分析,结合区域地质背景对沉积物来源和成因进行了探讨。识别出的沉积物波域主要位于台东峡谷与陆坡其他峡谷的交汇区,单个波形的波长为0.8～7.2 km,波高为18～75 m左右,呈NE—SW向展布。台东峡谷弯曲段内侧向上坡迁移的沉积物波,其底界发育块体流沉积,内部可细分为下部过渡单元和上部波形单元。弯曲段外侧的沉积物波呈垂向加积的特征,底部无块体流沉积。基于沉积物波的几何形态,估算整个波域的流体厚度在196～356 m之间,流体速度在15～21 cm/s之间。沉积物波的形态特征、内部结构、分布规律以及数值计算表明这些沉积物波为浊流成因。台湾东部海域沉积物波域的发育与台湾西南部的沉积物波域一样,是台湾造山运动的沉积响应。距今3.5 Ma以来花东海脊的形成以及广燠火山岛—绿岛—兰屿火山岛间闸口的抬升和封闭使得沉积物经由卑南溪及海下水道向南输送到绿岛西侧的台东海槽残留弧前盆地时受阻,转而沿台东峡谷及陆坡冲沟体系向东输送入花东海盆。浊流沉积物沿着峡谷/沟谷体系向下坡方向输送的过程中,在峡谷/冲沟的嘴部等地形限制性降低的位置卸载,或在台东峡谷的高弯曲段漫溢出来,从而形成沉积物波域。
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| 关 键 词： | 台东峡谷 沉积物波 浊流 成因机制 |
| 收稿时间： | 2017-12-04 |
Sediment Waves Characteristics and Origin of Taitung Canyon in Eastern Waters of Taiwan Island |
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| LIU Jie,SUN MeiJing,GAO HongFang,LI XueJie. Sediment Waves Characteristics and Origin of Taitung Canyon in Eastern Waters of Taiwan Island[J]. Acta Sedimentologica Sinica, 2019, 37(1): 155-162. DOI: 10.14027/j.issn.1000-0550.2018.106 |
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| Authors: | LIU Jie SUN MeiJing GAO HongFang LI XueJie |
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| Affiliation: | 1.Key Laboratory of Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China;2.Key Laboratory of Marine Mineral Resources, Ministry of Land and Resources, Guangzhou Marine Geological Survey, Guangzhou 510075, China |
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| Abstract: | Based on numerous high-resolution seismic profiles, sediment waves are identified in the eastern waters of Taiwan Island, and their distribution, morphological characteristics, internal structure, and potential origin are illustrated. The sediment waves are located at the junction of the Taitung canyon with other canyons on the slope. The wavelength of a single waveform is 0.8-7.2 km, and the wave height is about 18-75 m, which is a northeast-southwest (NE-SW) distribution. Sediment waves located inside the bend section of Taitung canyon have characteristics of upward migration, their bottoms develop MTD, and the interior can be subdivided into lower transition units and upper wavy units. The sediment wave on the outside of the bend is characterized by vertical accretion, and there is no mass flow deposit at the bottom. According to the sediment wave geometry, the flow thicknesses across the entire wave field are calculated as 196-356 m, and the current velocity falls in the range of 15-21 cm/s. The morphological characteristics, internal structure, and distribution of sediment waves and our numerical calculations show that these sediment waves are turbidity currents. The development of the sediment wave field in east Taiwan is the same as that of the sediment wave field in southwestern Taiwan. It is the sedimentary response of the Taiwan orogeny. Turbidity sediments overflow in the bend section of Taitung canyon or in places of less topographical constraint, thus forming a sediment wave field. |
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| Keywords: | Taitung Canyon sediment wave turbidity current formation mechanism |
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