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以松辽盆地齐家—古龙地区白垩系嫩江组一段为研究对象,通过地震沉积学、沉积构造和沉积序列等分析,发现异重流成因的大型水道—湖底扇系统,对大型坳陷湖盆深水区分布的异重流及其形成的异重岩进行研究,构建了陆相湖盆异重流成因的水道—湖底扇沉积模式。研究表明,异重流发源于盆地边缘,经北部三角洲后在深水区形成完整的水道—湖底扇系统。自北向南依次发育顺直水道和弯曲水道,直线延伸距离超过80 km,宽度100~900 m;水道末端发育湖底扇,最大面积可达20 km~2。该系统主要以细粒沉积为主,发育块状砂岩和流水成因的沉积构造,内部发育侵蚀接触面,富含陆源有机质碎屑,具底床载荷和悬浮载荷兼有的形成机制。异重岩沉积序列表现为向上变粗和向上变细的旋回成对出现,反映洪水逐渐增强随后又减弱的动力学特点。
Taking the first member of Cretaceous Nenjiang Formation in Qijia-Gulong area of Songliao Basin as the research object, through the analysis of seismo-sedimentology, sedimentary structure and sedimentary sequence, it is found that the large-scale channel - Heterogeneous flow distributed in the deepwater area and the heavy rock formed by them are studied, and the sedimentary model of water channel-subduction fan with heavy gravity in the continental lacustrine basin is established. Studies have shown that heavy flow originates from the margin of the basin and forms a complete waterway-sublacustrine fan system in the deepwater after the northern delta. From north to south, the straight and curved watercourses are developed in sequence. The straight line extends over 80 km and the width is 100 to 900 m. At the end of the waterway, the sublacustrine fan grows to a maximum of 20 km 2. The system is dominated by fine-grained sediments, with the development of massive sandstone and fluid-sedimentary structures. The erosion-contact surface is developed in-house and is rich in terrigenous organic debris with the formation mechanism of both bed load and suspended load. The sedimentary sequences of the hematite rocks are paired upwards with the upward thickening and the upward spiraling, reflecting the kinetic characteristics that the flood is gradually enhanced and then weakened.