Weathering and Erosion

Weathering and Erosion

Rock Cycle Revisited

What do volcanoes and tectonic activity do to the surface of the Earth?

Mt. Everest is increasing in height by approximately 2 inches each year.

Build it up!

Mechanical Weathering

The breaking down of rock by mechanical means. The smaller pieces retain the characteristics of the larger piece.

• Ice Wedging• Organic Activity• Abrasion

Organic Activity

Abrasion

Chemical Weathering

Chemical reactions alter the internal structure of rock breaking it down.

• Hydrolysis• Carbonation• Oxidation• Acid precipitation

Hydrolysis: Chemical reaction between minerals and water

Carbonation: Carbon dioxide and water combine to form a weak acid (carbonic acid)

Oxidation: When elements (especially metals) combine with oxygen

Acid Precipitation: Oxides of sulfur and nitrogen dissolved in water form acids (usually produced in industrial areas)

What factors affect the rate of weathering?

Factors that Effect Rates of Weathering?

• Rock Composition

Sandstone: Moh’s hardness of 5

Quartz: Moh’s hardness of 7

More Factors

• Amount of Exposure • Climate – what climate conditions or combination of conditions increase weathering?

• Warm moist climates• Variable temperatures

for freezing and thawing

Bill Nye - Erosion

SoilThe top 6 elements in the human body are

• Nitrogen• Carbon• Hydrogen• Oxygen• Phosphorous• Sulfur

Where do we get them from?

Soil is a combination of…

• Mineral matter• Organic matter• Water • Air

Humus = Organic Matter

Decayed plant & animal matter provides nutrients and helps with water retention

Not to be confused with Hummus

What influences the rate of soil production?

• Time• Climate• Plants & Animals• Slope

Soil,It’s Impoprtant!

soil

O = Organic LayerA = TopsoilB = SubsoilC = Parent Material

Below that = bedrock

Soil texture is important for…

• Agriculture• Engineering

Soil Texture TriangleThe rock material in soil is made up of• Clay (<0.002mm)

• Silt (0.002 – 0.6 mm)

• Sand (0.6 mm – 2 mm)