摘要
通过总结河流变迁规律,明确了辫—曲转换特征,建立了辫—曲过渡型河流的沉积序列;通过分析弯曲度与废弃河道沉积特征的相互关系,提出不同类型河流中存在分叉分流、串沟取直及颈项截直三类废弃河道,并提出三类废弃河道的分类依据,进而建立了相应的沉积模式。通过解剖北京西山军庄二叠系河流相野外露头,分析了辫状河、以曲流河及其过渡型河流的沉积特征与演变特点,识别出该露头中发育的废弃河道,进而明确该露头中产生辫—曲转换的地质因素是不同气候条件下,由于沉积供源的差异导致河道类型的变化。
Based on summing up the great variability and dynamic behavior of rivers, we analyzed the meander- brai-ded transition characteristics and constructed its sedimentary sequence. According to the relationship between sinuosity and abandoned channels, we divided abandoned channels into three patterns which are avulsion, chute cutoff- and neck cutoff- abandoned channel, respectively, and each pattern has its particular sedimentary sequence model. Fur-thermore ,by analyzing the sedimentary characteristics from a Permian fluvial outcrop located in Beijing western sub-urbs ,we clarified the evolution of braided, meander-braided transition and meandering channels and distinguished three abandoned channels. We reached the conclusion that the main factor leading to meander-braided transition in the study area is the change of sediment supply caused by different climate conditions.
出处
《沉积学报》
CAS
CSCD
北大核心
2017年第1期1-9,共9页
Acta Sedimentologica Sinica
基金
国家自然科学基金项目(41572080
41272132)
中石油华北油田重大科技专项(HBYT-YJY-2015-JS)~~
关键词
河流辫-曲转换
沉积序列
废弃河道
二叠系河流相
meander-braided transition of river
sedimentary sequence
abandoned channel
fluvial environment in Permian
