The depositional evolution and internal sedimentary architecture of a flood event-dominated experimental alluvial fan
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ORIGINAL PAPER
The depositional evolution and internal sedimentary architecture of a flood event-dominated experimental alluvial fan Wenjie Feng 1 & Shenghe Wu 2 & Junling Liu 1 & Changmin Zhang 1 & Yanshu Yin 1 & Taiju Yin 1 Received: 12 December 2018 / Accepted: 1 April 2019 # Saudi Society for Geosciences 2019
Abstract In this article, based on a flume tank experiment, we attempt to provide some key insights to the depositional process and geomorphological evolution of an experimental alluvial fan dominated by flood events. In the experiment, all boundary conditions were kept constant besides the sediment and water supply in each flood event. The experimental fan formed after 12 flood events. The elevation at the observation points was measured and the geomorphology evolution during the whole experiment was recorded by time-lapsed digital images. It is showed that the depositional process of the experimental fan could be subdivided into three stages, including the sheet flood-dominated stage, the unconfined channel-dominated stage, and the confined channeldominated stage. The spontaneous evolution of the experimental fan was indicated to be controlled by the continuously occupation of the accommodation space and resulted in the three-layer sedimentary architecture. With the growth of this experimental fan, the increasing rate of fan area and the vertically aggradational rate decreased. Meanwhile, the roughness of the fan edge changed from rapid fluctuation to gradually decrease. Keywords Flood event-dominated alluvial fan . Autogenic . Flume experiment . Depositional evolution . Sedimentary architecture . Geomorphology
Introduction Alluvial fan is a type of complex terrestrial sedimentary system that commonly developed at the margin of basins (Bull 1977; Al-Sarawi 1988; Stanistreet and McCarthy 1993; Brierley et al. 1993; Blair 1999a, 1999b). As for the alluvial fans, their depositional evolution, internal sedimentary architecture, and the reservoir configurations have received numerous concerns worldwide (Hooke 1967; Le Hooke and Rohrer 1979; Sorriso-Valvo et al. 1998; Clarke et al. 2010; Straub and Esposito 2013; Delorme et al. 2018). The piedmont setting of alluvial fans where the feeder channel of an upland drainage basin intersects the mountain front assures Editorial handling: B. Badenas * Wenjie Feng [email protected] 1
School of Geosciences, Yangtze University, Wuhan, China
2
State Key Laboratory of Petroleum Resource and Prospecting, College of Geosciences, China University of Petroleum (Beijing), Beijing, China
that catastrophic fluid gravity flows and sediment gravity flows, including sheet floods, rock falls, rock slides, rock avalanches, and debris flows, are major constructional processes, regardless of climate (Blair and McPherson 1994). Braided river and low sinuosity/meandering river also play an essential role on the formation of alluvial fans (Stanistreet and McCarthy 1993). Sedimentary process of alluvial fan is controlled alternately by flood periods and inter-flood periods. Alth
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