![]() It is these basic processes that give rise to the growth of sedimentary systems and to a large extent determine the internal sedimentary architecture. 2014).Īutogenic processes control the fundamental deposition of the sedimentary system, such as channel migration, avulsion, and abandonment (Clarke et al. The widely existing fining upward sequence in the meandering river reservoir and the coarsening upward sequence in the delta are typical autogenic deposits (Hajek and Straub 2017 Miall et al. As controlled by the within-basin factors only, the above processes are called autogenic processes (Miall et al. 2016 Hajek and Straub 2017, 2017 Hamilton et al. The periodic and spontaneous evolution of geomorphology has been observed in most of the terrestrial sedimentary systems (such as alluvial fan, fluvial delta, braided river, and meandering river) when the extra-basin factors were maintained approximately constant (Carlson et al. In order to clarify the controlling mechanism of each factor on the sedimentary system, Beerbower ( 1964) first classified the above factors into two types, including within-basin and extra-basin factors. There are a number of controlling factors that govern the depositional processes and the internal architecture of a sedimentary system including water and sediment supply, climatic changes, base-level variation, tectonic activities, and so on (Gong et al. Dynamic allocation of accommodation space and the following adaptive sediments filling were the two main driving factors of the autogenic evolution of deltas. The experimental delta consisted of six autogenic depositional successions. The three sedimentary layers formed in the three stages constituted an autogenic succession. In the late aggradational–progradational stage, the feeder channel branched into several radial distributary channels, overlapped distributary channels were formed on the delta plain, and terminal lobe complexes were formed at the end of distributary channels. These distributary splay complexes were retrogradationally overlapped due to the continuous migration of the bifurcation point of the feeder channel. In the middle retrogradational stage, the feeder channel was blocked by the mouth bar(s) which grew out of water at the end of the initial stage, and a set of large-scale distributary splay complexes were formed on the delta plain. In the initial progradational stage, one feeder channel incised into the delta plain, mouth bar(s) was formed in front of the channel mouth, and small-scale crevasse splays were formed on the delta plain. The evolution of river-dominated delta controlled only by autogenic process is obviously periodic, and each autogenic cycle can be divided into an initial progradational stage, a middle retrogratational stage, and a late aggradational–progradational stage. Through the flume tank experiment under constant boundary conditions, the depositional process, evolution principles, and the sedimentary architecture of a river-dominated delta was presented, and a corresponding sedimentary architecture model was constructed. ![]() However, autogenic processes are often affected by changing allogenic factors and are difficult to be identified and analyzed from modern and ancient records. Autogenic processes are widely found in various sedimentary systems and they play an important role in the depositional evolution and corresponding sedimentary architecture. ![]()
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