1.4 River gravel, sand and clay

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• Middelbare school
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• Leerjaar 2

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Instruction 1.4 River gravel, sand and clay

Quiz 1.1 - 1.4

Homework check

1.2 Rock changes: 2, 3, 8

1.3 Rock is moved 2, 4, 7, 8

A low-lying, flat area is called a plain.      
The lower course of the river flows through the plain.

The ground consists of meters-thick layers of sand, river gravel and clay.
This material was taken from the upper course via the middle course into the lower course. This process is called sedimentation.

New layers of sediment get increasingly thicker, and when this continues long enough, new land is created: a delta.

Dunes

Some of the sand from the rivers ends up in the sea and eventually it forms dunes.

Dunes

How are dunes formed? Enter the following terms on the dotted lines: waves, sandbanks, beach.

.................... bring sand to the ……………….. from ……………….. in the sea.

After each wave a little sand is left behind.

Dunes

How are dunes formed?

Waves bring sand to the beacht from sandbanks in the sea.

After each wave a little sand is left behind.

Dunes

How are dunes formed?
Enter the following terms on the dotted lines:
dune, obstacle, wind.


The ………..…. takes the sand land inwards until it reaches an ………..….
By a piece of wood or plant a little heap of sand is formed which over time becomes several metres high and forms a ……..……..

Dunes

How are dunes formed?

The wind takes the sand land inwards until it reaches an obstacle.
By a piece of wood or plant a little heap of sand is formed which over time becomes several metres high and forms a dune.

Sedimentary rock

In some places in the plain and at sea there are thick layers of sediment (sand and clay) kilometers deep.

Due to the pressure of the layers above, the sediment is compressed and sedimentary rock is formed.

Sedimentary rock

Sand -> Sandstone

Shells -> Limestone

Clay -> Shale

Sedimentary rock

How can you recognise sedimentary rock?

• You can still see layers and sometimes you find fossils in the rock.

Question

Which two types of weathering are there?

Question

Which two types of weathering are there?

Mechanical weathering and chemical weathering.

Give three examples of mechanical weathering.

Question

Which two types of weathering are there?

Mechanical weathering and chemical weathering.

Give three examples of mechanical weathering.

Due to freezing, due to temperature changes and due to roots of plants and trees.

Question

What is the most ideal climate for chemical weathering?

Question

What is the most ideal climate for chemical weathering?

A warm, humid climate.

Question

How do we call the falling down of loose rock down a slope?

Question

How do we call the falling down of loose rock down a slope?

Mass movement: falling down, sliding, rolling.

What do we mean with erosion?

Question

How do we call the falling down of loose rock down a slope?

Mass movement.

What do we mean with erosion?

The abrasive effect of running water, wind or ice is called erosion.

Question

In which part of the river do we find river gravel (pebbles)?

Question

In which part of the river do we find river gravel (pebbles)?

In the upper course.

What about sand and clay?

Different valleys

Which of the following valleys is formed by a river and which by a glacier?

Explain your answer.

Different valleys

Next week

Small test about 1.1 - 1.4