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Geomorphic Features Associated with Erosion
Published in Ramesh P. Singh, Darius Bartlett, Natural Hazards, 2018
Niki Evelpidou, Isidoros Kampolis, Anna Karkani
A waterfall corresponds to a broken section of a stream’s bed with continuous flow, characterized by an abrupt change of its topographic slope. It owes its formation to intense differential erosion or discontinuities (i.e. faults). The height from which the water flows in a waterfall ranges from a few metres to several hundreds of metres.
Surface Processes
Published in F.G.H. Blyth, M. H. de Freitas, A Geology for Engineers, 2017
F.G.H. Blyth, M. H. de Freitas
At the base of many coastal cliffs a wave-cut platform is formed, which slopes gently seawards (Fig. 3.22). The rocks of the foreshore are bevelled off and exposed on the platform, and may be partly covered by beach deposits. The sea exerts a ‘sawing’ action at the base of cliffs, cutting a horizontal notch which gradually weakens the cliff base. While this goes on, atmospheric denudation slowly wears away the upper part of the cliff and gravity induced shear stresses weaken it internally; slides and debris which fall to the foot of the cliff is broken up by the waves and largely removed into the offshore zone. Thus the cliff face recedes as it is undercut by waves and denuded by rain and frost; and as the wave-cut platform is widened the erosion at the cliff foot is slowed down. Streams which drain to the coast may be rejuvenated by the steepening of their lower courses, as cliffs are cut back; if this takes place faster than the streams can achieve a new grade, waterfalls are formed where the truncated valleys meet the cliff. Instances of truncated valleys are seen in the famous Chalk cliffs on the Sussex coast, e.g. the Seven Sisters.
Geotourism and geoparks for sustainable rural development and poverty alleviation: Huanggang Dabieshan UNESCO Global Geopark, China
Published in Australian Journal of Earth Sciences, 2022
The fluvial morphology of the DBGG is dominated by bedrock channels and high-energy, boulder-rich braided channels. Bedrock channels are abundant in the headwater sections of valleys but in many places the bedrock is concealed under recent debris flow deposits. Longitudinal stream profiles are irregular in shape, with multiple steps and knickpoint zones, locally reflecting the resistance of the bedrock and can be used as an indicator of ongoing uplifting and incision forming canyons and waterfalls. Waterfalls, which form on the streams of all sizes, range from free falling for more than 50 m to steep chutes to cascading staircases and are associated with potholes and other minor forms of bedrock erosion.