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台湾浅滩陆坡处于被动大陆边缘环境,发育众多的海底峡谷,其中台湾峡谷的走向与沿陆坡向下的侵蚀沟壑明显不同,呈近45°相交;在峡谷的下部又出现一次明显的转向,随后平行于陆坡自西向东延伸,最终汇入马尼拉海沟.本次研究利用多波速水深数据、高分辨地震资料和沉积柱状样,描述了台湾峡谷的地形地貌特征,初步讨论了峡谷的成因及其对沉积的控制作用.台湾峡谷的地形、地貌和沉积特征具有分段性:上段以侵蚀作用为主,呈V形下切,广泛发育滑动、滑塌等重力流类型;中段以侵蚀-沉积过渡作用为主,呈U形,发育内堤岸;下段以沉积作用为主,发育沉积物波,底流对峡谷内部沉积物有明显的改造(reworked sand).台湾峡谷的形成演化与沉积物供给、重力滑动(滑塌)、断裂活动和海底刺穿密切相关:(1)由于陆源碎屑物质供应较充足,陆架边缘沉积物不断向海方向推进,在前缘形成滑动、滑塌,为峡谷的形成提供了动力;(2)断裂活动导致地层破碎,重力流优先侵蚀较脆弱的地层,使峡谷的延伸方向与周边侵蚀沟壑呈明显斜交;(3)海底刺穿形成海山,由于海山的阻挡作用,峡谷的下段转为近东西走向,同时大量沉积物在拐弯处溢流出来形成沉积物波.
Taiwan Shoal slope in the passive continental margin environment, the development of many submarine canyons, of which the trend of Taiwan’s Canyon and the slope along the slope of the erosion gully significantly different, was nearly 45 ° intersection; in the lower reaches of the valley there is a clear turn, followed by parallel Which extends from west to east on the slope and finally flows into the Manila trench.This study described the topography of Taiwan canyon using multiwave depth, high resolution seismic data and sedimentary column samples, and discussed the causes of the canyon and its influence on sediment . The topography of the canyon in Taiwan is subdivided into topography, sedimentation and topography. The upper segment is dominated by erosion and is undercut by the V-shape. Gravity flow types such as slip and slump are widely developed. The middle part is dominated by the erosion-sedimentation transition , Which is U-shaped with inner embankment developed. In the lower part, sedimentary waves and underflow mainly reworked the sediments in the gorge. The formation and evolution of the Taiwan canyon and the sediment supply, (1) Due to the sufficient supply of terrigenous clastic material, the sediments on the edge of the shelf are continuously advancing toward the sea, and (2) Fracture activities lead to crustal fractures, and gravity flow preferentially erodes the more vulnerable strata, so that the extension direction of the canyon is obviously oblique to the surrounding erosion gully. (3) Seabed piercing formation Seamount, due to the blocking seamounts, the lower reaches of the canyon to near the east-west direction, while a large number of sediment overflows at the bend to form sediment waves.