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Weathering and Erosion. Rock Cycle Revisited. What do volcanoes and tectonic activity do to the surface of the Earth?. Build it up!. Mt. Everest is increasing in height by approximately 2 inches each year. Mechanical Weathering.
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What do volcanoes and tectonic activity do to the surface of the Earth? Build it up! Mt. Everest is increasing in height by approximately 2 inches each year.
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
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)
Factors that Effect Rates of Weathering? Quartz: Moh’s hardness of 7 Sandstone: Moh’s hardness of 5 Rock Composition
More Factors • Amount of Exposure • Climate – what climate conditions or combination of conditions increase weathering? • Warm moist climates • Variable temperatures for freezing and thawing
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
What influences the rate of soil production? • Time • Climate • Plants & Animals • Slope
Soil,It’s Impoprtant! O = Organic Layer A = Topsoil B = Subsoil C = Parent Material Below that = bedrock soil
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)