摘要
根据比较沉积学原理 ,论述了现代网状河沉积的沉积过程、沉积韵律特征、平面形态及其环境背景 ,进而对古代相关沉积类型进行了比较研究 ,对网状河的形成机制进行探讨和总结 。
Based on the theory of comparative sedimentology, this paper gives the detailed description of both the modern anastomosed river (Qiqihaer Nenjiang section) and the corresponding ancient ones(Huanghua depression and Qaidam basin). The paper presents the depositional processes,characteristics of sedimentary rhythm,geometry and heterogeneity of the modern anastomosed river with a reference material home and abroad, and generalizes the depesitiomal model. The river in Qiqihaer has the following features, that is, low slope gradient, small with/depth ratio, fast aggradation rate, the channel anastomosed, and confined lateral migration, and soon. The river can be divided into six sub-facies such as anastomosed channel, natural levee, crevasse splay, river beach, inter-river lake, and swamp. All provide the basis for the analysis of ancient corresponding reservoir quality sand bodies. The ancient anastomosed river, influenced by post-depositional physical or chemical reaction such as diagenesis, presents relative difference compared with the modern one, but both have similar sedimentary characteristics in morphology, environments, sand body structure, rhythm, and so on. It is this similarity that provides the basis of comparative sedimentology and its application. The authors discuss the formation mechanism on the anastomosed river so as to put forward a general discipline as a direction for further study. The river's formation is controlled by various factors, the authors explore that it is related to the low slope gradient, massive vegetation, flood development, and the uniform development. Sometimes the anastomosed river can be transformed from braided river. With the knowledge and comparative study on both the modern and ancient anastomosing river, we can analyse geometry, continuity, and heterogeneity of underground related sand bodies, which is very important in the course of exploration and development of petroleum.
出处
《沉积学报》
CAS
CSCD
北大核心
2000年第2期221-226,共6页
Acta Sedimentologica Sinica
关键词
比较沉积学
网状河
沉积模式
非均质性
沉积学
comparative sedimentology anastomosed river depositional model heterogeneity
