GRG 301C Lecture Notes - Lecture 8: Sediment Transport, Sea Level Rise, Alluvial Fan
22 Feb 2017
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Document Summary
Sand ripples, mega ripples (dunes) [localized landforms: point bars. Water slows down along the inner sections of the meanders which causes sediment deposition: along the river valley, natural levees. Built by floods as water overflows the channel it quickly loses its sediment transport capacity and begins to deposit the coarsest load: floodplains. Fine sediments (fine sands, silts, and clays) deposited. Overflowing discharge typically occurs once every 1-2 years: terraces. Remnant floodplain deposits no longer flooded by current river. Where the river continued cutting down and formed a new lower floodplain: at the end point of a catchment, watershed, or basin, alluvial fan. "fan" shaped deposits accumulating along steep mountain fronts. Where steep mountain streams in narrow valleys emerge into a low gradient flat valley. Drop in gradient and confinement promotes deposition: delta. Sediment-rich streams enter a lake, inland sea or the ocean [reaches base level] Flow slows down promoting deposition which decreases slope until channel is choked.
