Weathering and Erosion

Summary

Weathering breaks rock in place; erosion removes and transports the resulting material by water, wind, ice or gravity.

Core idea

Understand the system

Weathering breaks rock in place; erosion removes and transports the resulting material by water, wind, ice or gravity.

Why and how it happens

Causes and context

Weathering breaks rock in place; erosion removes and transports the resulting material by water, wind, ice or gravity. The governing relationship is: Physical, chemical and biological weathering weaken material, after which moving agents entrain, transport and deposit sediment.

How it works

Physical, chemical and biological weathering weaken material, after which moving agents entrain, transport and deposit sediment.

Key facts

• Weathering is in situ; erosion involves removal.
• Hydrolysis, oxidation, carbonation and solution are chemical weathering processes.
• Abrasion is wearing caused by transported particles scraping a surface.

Important terms

• weathering
• erosion
• abrasion
• mass wasting
• denudation

Examples and case studies

• River incision and slope wash in the Himalaya supply sediment to the Ganges-Brahmaputra delta.

Causes and components

• Key components: weathering, erosion, abrasion.
• Physical, chemical and biological weathering weaken material, after which moving agents entrain, transport and deposit sediment.

Effects and significance

• Hydrolysis, oxidation, carbonation and solution are chemical weathering processes.
• Abrasion is wearing caused by transported particles scraping a surface.
• Application: River incision and slope wash in the Himalaya supply sediment to the Ganges-Brahmaputra delta.

Geography connection

River incision and slope wash in the Himalaya supply sediment to the Ganges-Brahmaputra delta. This illustrates how weathering and erosion varies by location, scale or environmental context.

Bangladesh connection

Riverbank erosion along the Jamuna and braided channels displaces land and settlements, while weathering supplies sediment from uplands.

BCS preliminary facts

• Weathering is in situ; erosion involves removal.
• Hydrolysis, oxidation, carbonation and solution are chemical weathering processes.
• Abrasion is wearing caused by transported particles scraping a surface.

BCS written analysis

Build an analytical answer

• Weathering breaks rock in place; erosion removes and transports the resulting material by water, wind, ice or gravity.
• Physical, chemical and biological weathering weaken material, after which moving agents entrain, transport and deposit sediment. Use river incision and slope wash in the himalaya supply sediment to the ganges-brahmaputra delta. as a named application in a comparative answer.

Common misconceptions

• Deposition is not erosion; it is the settling of transported material.
• Weathering does not require movement of material.

Quick revision

• Weathering and Erosion
• Weathering is in situ; erosion involves removal.
• Hydrolysis, oxidation, carbonation and solution are chemical weathering processes.
• weathering / erosion
• Definition → process → spatial example