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Frost Heaving. Plant Roots (Root Pry). Talus. Talus. Water. Burrowing of Animals. Chemical Weathering. The process that breaks down rock through chemical changes. New substances can be formed. Agents/Types of Chemical Weathering
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Talus Talus
Chemical Weathering • The process that breaks down rock through chemical changes. New substances can be formed. • Agents/Types of Chemical Weathering • Carbonic Acid-in rainwater. Forms caves/karst. • Oxidation (rust) • Living organisms (lichens/mosses) • Humic Acid-from decaying organic matter.
Carbonic Acid • in water weathers mainly limestone and dolomite by dissolving these rock types. 7
Carbon Dioxide • CO2 dissolves in rain water and creates carbonic acid • Carbonic acid easily weathers limestone, dolomite, and marble
Oxygen • Iron combines with oxygen in the presence of water in a processes called oxidation • The product of oxidation is rust
Living Organisms • Lichens that grow on rocks produce weak acids that chemically weather rock
As the particles get smaller, the total surface area available for chemical weathering increases.
Soil: A product of weathering. • Soil Composition - Soil has four major components: • 1. Mineral matter, or broken-down rock • 2. Organic matter or humus, which is the decayed remains of organisms • 3. Water • 4. Air. • Soil Texture = refers to the proportions of different particle sizes. (Loam, Sand, Silt, Clay).
What affects Soil Formation? • 1. Time! More time means a thicker, more developed soil with clear horizons. • 2. Climate! Probably has the larges affect on soil formation. Soil forms most quickly in humid, warm, wet climates. • 3. Organisms. An abundance or lack of organisms can affect the physical and chemical nature of a soil.
Special Types of Soils • Loess: Wind blown, angular silt that is usually the product of glaciers or wind blown volcanic ash. • Caliche: Soil primarily made of carbonate (limestone) found in arid areas. • Peat: Accumulation of partially decayed organic matter. Found in swamps/bogs • Paleosol: A fossil soil.