Earth Science: Weathering, Erosion, Deposition PDF

EARTH SCIENCE SURFACE PROCESSES: WEATHERING.EROSION.DEPOSITION WEATHERING. EROSION. DEPOSITION  WEATHERING. EROSION. DEPOSITION Mass wasting is the movement of rock and soil DOWN SLOPE under the influence of GRAVITY. Rock falls, slumps, and debris flows are all examples of mass wasting. WEAT...

EARTH SCIENCE SURFACE PROCESSES: WEATHERING.EROSION.DEPOSITION WEATHERING. EROSION. DEPOSITION  WEATHERING. EROSION. DEPOSITION Mass wasting is the movement of rock and soil DOWN SLOPE under the influence of GRAVITY. Rock falls, slumps, and debris flows are all examples of mass wasting. WEATHERING. EROSION. DEPOSITION  BREAKING OF ROCKS TRANSPORTATION OF SEDIMENTS (FRAGMENTS OF ROCKS) DROPPING OF SEDIMENTS TO NEW POSITION/LOCATION AGENTS OF WEATHERING WATER WIND ACIDS ICE BIOLOGICAL TEMPERATURE ACTIVITIES TYPES OF WEATHERING Mechanical Weathering also known as Physical Weathering Chemical Weathering Biological Weathering TYPES OF WEATHERING No change in chemical composition Same mineral components Change in size due to the interaction of rocks with ice, wind, water, and living organisms TYPES OF WEATHERING PHYSICAL WEATHERING ❑ Abrasion ❑ Freeze-thaw ❑ Exfoliation ❑ Physical weathering by biological means  PHYSICAL WEATHERING- ABRASION It occurs when rocks surface is frequently exposed to water, wind, and gravity. PHYSICAL WEATHERING- FREEZE-THAW It occurs when water continually seeps into cracks, freezes, and expands, eventually breaking the rock  PHYSICAL WEATHERING- FREEZE-THAW Alternate freezing and thawing form potholes and frost heave. PHYSICAL WEATHERING- FREEZE-THAW Water collects in Ice thaws, contracts Repeated expansion rock crack, joints, or and water gets deeper pores and contraction Water freezes and into cracks again cause further cracks expands, forcing till rock splits or cracks to widen breaks PHYSICAL WEATHERING- EXFOLIATION It occurs when there is dramatic change in temperature alternating hot and cold temperatures weaken the rock as it expands and contracts.  PHYSICAL WEATHERING- BIOLOGICAL WEATHERING BY PHYSICAL MEANS Burrowing animals like snakes and earthworms create holes on the ground by excavation and move the rock fragments to the surface. These fragments become more exposed to other environmental factors that can further enhance their weathering. Furthermore, humans also indirectly contribute to biological weathering by different activities that cause rocks to break. TYPES OF WEATHERING change in chemical composition May change in color due to the chemical reaction of rocks with substances such as acids and oxygen TYPES OF WEATHERING CHEMICAL WEATHERING ❑ Carbonation ❑ Hydrolysis ❑ Hydration ❑ Oxidation ❑ Chemical weathering by biological means CHEMICAL WEATHERING - CARBONATION It occurs when water combines with carbon dioxide in the air to form carbonic acid. Carbonic acid easily dissolves rocks like limestone and marble. CHEMICAL WEATHERING - CARBONATION CHEMICAL WEATHERING - OXIDATION the breakdown of rock by oxygen and water, often giving iron rich rocks a rusty- colored CHEMICAL WEATHERING - HYDROLYSIS The term hydrolysis combines the prefix hydro, referring to water, with lysis, which is derived from a Greek word meaning to loosen or dissolve. Thus, you can think of hydrolysis as a chemical reaction where water loosens the chemical bonds within a mineral and produces a different mineral in addition to ions. An example of hydrolysis is when water reacts with potassium feldspar to produce clay minerals and ions. CHEMICAL WEATHERING - HYDROLYSIS CHEMICAL WEATHERING - HYDRATION Hydration reactions involve water being added to the chemical structure of a mineral. An example of a hydration reaction is when anhydrite (CaSO4) is transformed into gypsum (CaSO4·2H2O) CHEMICAL WEATHERING – BIOLOGICAL MEANS FACTORS AFFECTING THE RATE OF WEATHERING Exposure Particle size Mineral Composition Climate FACTORS AFFECTING THE RATE OF WEATHERING Exposure The rate and type of weathering are dependent on exposure to air, water and living things. The greater the amount of rock exposed, the greater the weathering. FACTORS AFFECTING THE RATE OF WEATHERING Particle Size- an increase in surface area increases the rate of weathering. FACTORS AFFECTING THE RATE OF WEATHERING Mineral Composition-rocks made of harder minerals weather slower than rocks made of softer minerals. Fast Weathering Rate of Slow Mineral Hardness FACTORS AFFECTING THE RATE OF WEATHERING 4. Climate-physical and chemical weathering are affected by climate. a.In cold and moist climates, physical weathering is dominant. b. In hot and moist climates, chemical weathering is dominant.