Thursday, 22 March 2012

Mass Wasting

Types of Mass Wasting
Scree- When water enters rocks and then freezing which causes the rock to shatter and tumble down the face of the cliff

Soil Creep- When soil is loose and so it adjusts causing a tree to tilt.

Landslide- Rapid movement of soil down slope caused by heavy weight on unstable rock

Mudflow-Water absorbs so much water that it flows downhill mixing with soil creating mud

Slump- Slab of land breaks away of slips a short distance down slope

Avalanche-Mass of snow and ice that breaks away and slides down a mountain slope

Soil Solution- Invisible form of mass wasting when dissolved soil is moved by water horizontally and vertically

Sunday, 18 March 2012

Erosion vs Weathering

Weathering is the breakup of rocks and erosion is the transportation of these weathered rocks.

Different types

Physical includes
-Frost shatter: Occurs in the northern and temperate regions. Occurs when water enters pores and cracks and ultimately freezes causing the rock to expand and crack.

-Thermal expansion: Occurs in desert regions where there is a considerable difference in temperature between the day and night. Heating takes place during the day and expansion occurs. This heat is lost during the cool nights and this contraction of the rocks cause them to break,

-Exfoliation: Occurs when thin layers of rock peel of the outer surface of the rock face due to wind and sand.

Chemical Weathering

Solution: Occurs when carbonic acid rain dissolves limestone and other rocks.

Hydrolysis:Carbonic acid works on minerals called silicates and this water replaces the silicate ions which results in the transportation of dissolved minerals away from the rock leaving clay.

Oxidation: Occurs when a metal is in the presence of oxygen. This form of weathering causes rust on metals( such as hammers)