Sorting of Sediments and Deposition
Agents of Deposition
• The agents of erosion are also agents of deposition.
• Depositional rate depends on sediment size, shape and density.
• Depositional rate also depends on characteristics of the depositional agent.
Speed or velocity
Agents of Deposition
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Settling Rate Vs. Velocity
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Velocity
Settl
ing
Rate
Settling Rate Vs. Density
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Density
Sett
ling
Rate
Settling Time Vs. Rate
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Settling Time
Sett
ling
Rate
Mountain side
Stream
Lake
As the stream enters the lake or an ocean, the stream velocity decreases
and sediments are deposited.
Stream velocity
decreases
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Horizontal Sorting
BouldersCobbles
PebblesSand Silt Clay
Region of maximum stream velocity changes when streams bend or turn. There is an interface between regions of erosion and deposition…
Stream
BouldersCobblesPebblesSand
Vertical SortingClay
Silt
Vertical Sorting
Vertical Sorting
•-Vertical Sorting
Latest layer
Earliest layerLater layer
•Vertical sorting can occur as a single depositional event in still water or a series of events as when a stream’s velocity decreases through the seasons allowing particles to settle in a -
Vertical Sorting
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Named for the Greek letter
Stream
Ocean
Deltas
Mississippi Delta• Sediment-laden
river water mixes with cold, deep-sea currents, creating a nutrient rich zone where both salt and freshwater fish flourish.
• Wind--• -
Deposition by other agents of erosion
Crossbeds in a Sand Dune
Unsorted Sediments
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Final Question
• What are the factors that affect the settling rates of sediments?
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