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

Soil The 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 Layer A = Topsoil B = Subsoil C = Parent Material Below that = bedrock

Soil texture is important for… Agriculture Engineering

Soil Texture Triangle The rock material in soil is made up of Clay (<0.002mm) Silt (0.002 – 0.6 mm) Sand (0.6 mm – 2 mm)