【摘要】 以地震资料为基础,对南海北部第四系深层等深流沉积进行了研究。南海北部水深约1200～3000m范围内发育大型长条状漂积体、限制型漂积体、陆坡席状漂积体及沉积物波。大型长条状漂积体外形为丘状,水道在靠陆一侧发育。限制型漂积体主要沉积于地形突起之间的地势相对低洼处,外形多平坦,水道较为发育。陆坡席状漂积体外形为席状。沉积物波面积较大,部分与漂积体伴生。深层等深流在自北东向南西沿南海陆架运动过程中,在中上陆坡由于地形变化相对较大及科氏力作用影响形成螺旋型等深流,进而产生次生环流,形成大型长条状漂积体及限制型漂积体。在中下陆坡因地形相对平坦、开阔,等深流为层状水流,多形成陆坡席状漂积体。本研究不仅能提高对南海深层等深流沉积的认识,还能为油气勘探服务。更多还原

【Abstract】 Quaternary deep water contourites were studied based on seismic data in northern South China Sea(NSCS).Giant elongated drifts,confined drifts,slope sheeted drifts and sediment waves were found between about 1200 m and 3000 m water depth in NSCS.Giant drifts showed mounded morphology with moats on the landward flank.Confined drifts were developed in the negative relief among topography prominences,where were relative flat and with moats.Slope sheet drifts displayed with sheet morphology.Large scale of sediment waves were generated partially associated to drifts.When deep water contour current moved from northeastern to southwestern,because of relatively obvious topographical change and Coriolis force,helical contour current was produced and secondary circulation appeared in further and formed giant elongated drifts and confined drifts in the upper-middle slope.However,tabular contour current may produce slope sheet drifts for flat and unrestricted environment in middle-low slope.This study was not only helpful to improve the recognition of deep water contourite,but also was beneficial to serve the hydrocarbon exploration.更多还原