沉积环境系指沉积物形成时期的外界条件.它包括地质、地貌情况,水动力条件,水介质的物理与化学性质,物质的来源、途径和多寡,以及生物作用等.古今沉积序列的研究都是为了分析和解释沉积环境,因为沉积环境的研究在地层对比、古地理的恢复和新构造运动中具有重要的科学意义.同时,它对寻找沉积矿床、分析油气的生成、运移、储集与保存条件,进而评价含油气远景具有重大的现实意义.我队在开展南海北部大陆架地质-地球物理综合调查研究中,进行了八年(1971—1978)的野外工作,包括样品在内的第一性资料较为丰富,近年来进行了广泛而深入的研究,本文着重讨论表层沉积物的沉积环境.一、大陆架沉积物概述根据野外调查资料,南海北部大陆架50米水深以外广泛分布着以细砂为主的灰黄色、黄褐色粗碎屑沉积,重矿物为金红石-钛铁矿组合,合较多的不稳定矿物,铁锰质、有机质含量较低,碳酸钙含量较高.该沉积物中有的贝壳、有孔虫壳体被海绿石(图版 Sedimentary environment refers to the external conditions during the formation of sediments, including the geological and geomorphological conditions, the hydrodynamic conditions, the physical and chemical properties of the aqueous medium, the sources, the ways and amounts of the materials, the biological functions, etc. Both ancient and modern sedimentary sequences Is to analyze and explain the sedimentary environment because the study of sedimentary environment has important scientific significance in stratigraphic correlation, palaeogeographic restoration and neotectonic movement.At the same time, it is of great significance to find sedimentary deposits, analyze the formation, migration and accumulation of oil and gas And preservation of conditions, and thus evaluate the future of oil and gas has great practical significance.Our team in the north of the South China Sea continental shelf geology - geophysical survey, conducted eight years (1971-1978) fieldwork, including samples, including One of the more abundant data, extensive and in-depth research in recent years, this article focuses on the depositional environment of surface sediment.First, continental shelf sediment overview According to field survey data, the South China Sea continental shelf outside the water depth of 50 meters widely distributed with fine sand Mainly gray-yellow, tawny coarse clastic sediments, heavy minerals rutile - ilmenite combination, combined with a lot of instability It was ferromanganese quality, low organic matter content, a high calcium carbonate content. Some of the deposit shell, glauconite is FORAMINIFERAL housing (Plate