Weathering and river processes

Question 0

Why is weathering important?

Answer 0

Weathering is a very helpful process. It has been in Involved in the formation of most of the soil and the covers of the earths surface.

Question 1

What is weathering?

Answer 1

The definition of weathering is the decay and disintegration of rocks in situ, involving physical, chemical and biological processes

Question 2

Erosion

Answer 2

There are four processes of river erosion

Corrasion- where sand and pebbles are dragged along the river bed, wearing it away.

Attrition- where rocks and stones wear each other away as they knock together,becoming smaller and more rounded.

Hydraulic action- where fast flowing water us forced into cracks, breaking up the bank over time.

Solution- where rocks such as limestone are dissolved in acid rainwater.

Question 3

Deposition

Answer 3

Deposition occurs when a river loses velocity (energy). This can be caused by

A decrease in gradient
A decrease in river flow as water drains away after heavy rain
A river meeting the sea or a lake, often forming a delta
The river flowing more slowly on the inside of bends.

Question 4

River channel patterns

Answer 4

Meandering- the river flows in a series of broad bends.
Straight- there are very few bends in the channel.
Braided- the river continually splits into smaller channels and then re joins flowing around banks of material that it has deposited. When there is a lot of water flowing in the river, the small channels may join up for a time to form one large river.

Question 5

Oxidation

Answer 5

Oxidation is the addition of oxygen to a mineral. The process affects rocks in dry areas where there is oxygen in contact with the rocks.
Rocks that contain iron are affected by oxidation.

Question 6

Types of weathering processes

Answer 6

Physical- freeze thaw action
Exfoliation
Chemical- carbonation
Oxidation
Biological- wedging effect of tree roots
Release of acids and carbon dioxide
Vegetation trapping water