Deposition of Eroded Sediments - Earth Sci · of deposition (how fast the particles fall to the bottom of a column of water) also increases. Particle size Settling rate (or speed)

Deposition of

Eroded

Sediments

• Deposition is the laying down (or dropping) of weathered sediments that have been transported by some agent of erosion.

What is deposition?

•Because running water is the dominant agent of erosion, most deposition occurs in bodies of water like lakes and oceans.

When and where does Depostion occur?

•When an agent of erosion loses its carrying power, the sediments are deposited.

What agents of erosion can deposit sediments on land?

Wind

Glaciers

Gravity

Settling time vs. Settling rate?

Deposition occurring.










Deposition has occurred.


Settling time refers to the time it took for the sediment to fall to the bottom.

Settling rate or speed = the distance divided by the time it took the sediment fall.

Factors that affect deposition:

• Particle size

• As particle size

increases the rate

of deposition

(how fast the

particles fall to

the bottom of a

column of water)

also increases.

Particle size

Settling

rate (or

speed)

Stream velocity and Sediment

Size (ESRT pg. 6)

• Stream velocity

generates kinetic

energy. The faster a

stream is flowing, the

more energy it has.

• As stream velocity

increases, the volume

and size of sediments

being carried also

increases.

Velocity of stream

Volume

and

particle

size

Particle shape...

• Smooth rounded

particles will

settle out more

quickly than

flatter more

irregularly

shaped particles.

Particle density...

• Denser

particles will

fall faster than

less dense

particles of

similar size and

shape. Particle density

Settling

rate

Types of Deposition: Horizontal Sorting

Pebbles

Incoming

stream with

sediments

The biggest sediments will be deposited first.


Pebbles

Incoming

stream with

sediments

As velocity decreases, smaller and smaller sediments are deposited.

Sand


Pebbles

Incoming

stream with

sediments


Sand

size Silt

Size


Pebbles

Incoming

stream with

sediments


Sand

size Silt

size Clay

size


Pebbles

Conglomerate

Incoming

stream with

sediments

Over time, the sediments will form layers and produce sedimentary rock according to sediment size.

Sand

Sandstone

Silt

size Clay

size

Siltstone Shale

Evaporites

Limestone


Pebbles

Conglomerate

Incoming

stream with

sediments

Over time, the sediments will form layers and produce sedimentary rock according to sediment size.

Sand

Sandstone

Silt

size Clay

size

Siltstone Shale

Evaporites

Limestone

Types of Deposition: Vertical Sorting

Vertical sorting happens when landslides occur under water at the continental shelves and slopes.

Vertical Sorting

Types of Deposition: Vertical Sorting

Largest Sized Sediments

Smallest Sediments

Agents of Deposition & Features

a) Stream deposition - Horizontal sorting usually occurs as the running water enters the calm waters of a lake or ocean.

Delta - A triangular or fan shaped deposit from streams and rivers as they enter larger bodies of water.

Mt. Pinatubo (S. America) from space.

Two of the world’s largest deltas.


Flood Plain – A flat land area surrounding a river that is occasionally flooded.

50/100 Year – The area that was flooded during the worst flood of the last 50 or 100 years. It is used to plan where buildings should or should not be built.

Landscape Development

Location of Proposed New High School


b) Wind deposition – Sediments are usually well sorted and form sand dunes which can show crossing bedding.

c) Deposition by Gravity – Sediments are often unsorted and can be found at the bottom of a cliff called Talus.

Deposition by Glaciers – occurs several different ways producing many different

landscape features.

Documents

Deposition of Eroded Sediments - Earth Sci · of deposition (how fast the particles fall to the bottom of a column of water) also increases. Particle size Settling rate (or speed)