【摘要】 对冲绳海槽西部陆坡上两个航次 (95航次和 99航次 )共计 2 0 0 0多公里的单道地震资料进行分析和解译 ,对斜坡沉积环境下沉积体系发育、分布特征进行了研究。结果表明 :a)冲绳海槽西部斜坡环境下 ,上新世以来的沉积层均不同程度的变形和错动 ;b)存在两种斜坡相地震反射模式———退覆模式和叠覆模式 ,这两种模式都反映了冲绳海槽西部陆坡得到充足的沉积物供给 ;c)斜坡环境下主要发育陆架边缘三角洲、重力流沉积和水道充填等沉积体系 ;d)沉积层发育特征表明 ,冲绳海槽西部陆坡具有北段坡度缓、沉积物供应丰富、构造相对不活跃 ,中段坡度陡、沉积物供应充足、构造活动强烈 ,南段坡度陡、沉积供应相对较少、构造和火山活动十分强烈 3种主要沉积环境。西部陆坡的沉积特征也揭示了东海陆架向陆坡提供了大量碎屑沉积物质。更多还原

【Abstract】 The Okinawa Trough is an active back-arc basin. In order to better understand the character,development and evolution of this trough,deposit systems and deposit processes in the slope,were analyzed and interpreted using 2000 line-km high-resolution single channel seismic reflection profiles (collected from cruises in 1995 and 1999). Studies have shown that Pre-Pliocene and Pliocene-Holocene strata had been distorted by normal faults. New data refutes the viewpoint that modern sediments have not been distorted. Two seismic reflection models were identified in the west slope of the Okinawa Trough: offlapping and uplapping. Results from both infer the west slope has rich sediment supply. Dominant depositional systems in the west slope include continental margin delta,gravity flow deposits and channel (or canyon)-filled deposits. Three depositional frameworks were summarized in the west slope of the Okinawa Trough corresponding to three depositional environments: a) slow slope,rich sediment supply with poor tectonic movements in the northern segment;b) steep morphology,rich sediment supply with violent tectonic movements in the middle segment;c) steep morphology,poor sediment supply with violent tectonic movements in the southern segment.更多还原