摘要
台湾东部峡谷的研究程度较低,对其沉积特征及成因缺乏系统的论述.利用近年来在台湾东部海域获得的地震剖面,对台东峡谷的形态特征、沉积充填以及成因进行了详细的分析.台东峡谷主体位于花东海盆,该部分水深在4 000～5 500 m范围内,以NE方向为主,长度约为160 km,宽度为0.2～14 km.根据峡谷的平面延伸特征,可以将台东峡谷分为3个区段:上游段为NE-NEE走向段、中游段为NE-NNW走向段、下游段为NE走向段直到峡谷嘴部;下切谷剖面形态从上游段的"V"型、中游段的复合形态("UV"并行)逐渐过渡到下游段的"U"型.台东峡谷上游段-中游段滑塌构造发育,峡谷转弯处的侧翼可见波状沉积,其下游段则以沉积充填为主.台东峡谷的成因与构造作用、地形特征和深水沉积作用关系密切.受西南高东北低的地形特征及基底隐伏断裂控制,峡谷总体呈现NE向延伸;重力流作用为峡谷的下切侵蚀和充填提供了动力与物质来源,峡谷从上游段到下游段下切侵蚀能力减弱,谷底充填增厚;峡谷中游段受海山的阻挡,发生转向;峡谷下游段因多条峡谷携带的沉积物汇入和"喇叭状"地形的影响,输送的沉积物在出加瓜脊末端后,形成了大型深水扇.
There is a lack of systematic discussion on the sedimentary characteristics and causes of Taitung Canyon. The morphological features,sedimentary filling characteristics and origin of Taitung Canyon are analyzed by using the single-channel and multi-channel seismic profiles recently acquired in eastern Taiwan. Taitung Canyon is mainly located in the Huatung Basin and is generally oriented NE oriented with a length of 160 km,a width of 0.2-14 km in the water depth of 4 000-5 500 m.The Taitung Canyon can be divided into three types in profile shape： V,U,complex types and three segments in plane： upper,middle and lower segments,which are NENEE-striking,NE-NNW-striking and NE-striking respectively. Mass movements such as slides or slumps are ubiquitous in the upper of Taitung Canyon,which are driven by a variety of erosional processes from gravity flow erosion to turbidity current. Wavy deposition can be observed in the flank of the middle section of Taitung Canyon,which may be formed by turbidity current. The sufficient deposits could be discharged at the lower of Taitung Canyon,where the modern submarine fan developed.The formation and development of the Taitung Canyon resulted from the interaction between the tectonic activity,topography and deep-water deposition. Upper segment is controlled by topography and deep-water deposition. Gravity flow deposition provides a material and power source for the erosion and fills in the canyon.The middle segment is controlled by tectonism,which Gagua Ridge changes the orientation of the middle reach of Taitung Canyon; The deep-water fan,located at the end of Taitung Canyon,is controlled by＂trumpet＂topography.When they get rid of the lat-eral constraints from Gagua Ridge,the debris occur to unload,resulting in a large deepwater fan.
作者
孙美静
高红芳
李学杰
Sun Meijing;Gao Hongfang;Li Xuejie(Key Laboratory of Marine Mineral Resources,Ministry of Land and Resources,Guangzhou Marine Geological Survey,Guangzhou 510075,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2018年第10期3709-3718,共10页
Earth Science
基金
国土资源部海底矿产资源重点实验室开放基金(No.KLMMR-2015-A-11)
中国地质调查局项目(Nos.GZH201300502
DD20160138
DD20160140
1212011220117
GZH201400202
1212011220116
GZH201100301)
关键词
花东海盆
台东海底峡谷
形态特征
深水沉积
沉积学
Huatung Basin
Taitung Submarine Canyon
morphological features
deepwater sedimentation
sedimentology
