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WEATHERING: Is the breakup of rock due to exposure to processes that occur at or near Earth’s surface. Types of Weathering. Chemical Weathering. Mechanical Weathering. Chemical Weathering. Biomechanical Weathering. Biochemical Weathering. Biomechanical Weathering. Biochemical Weathering.
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WEATHERING: • Is the breakup of rock due to exposure to processes that occur at or near Earth’s surface
Types of Weathering Chemical Weathering Mechanical Weathering Chemical Weathering Biomechanical Weathering BiochemicalWeathering Biomechanical Weathering BiochemicalWeathering
Abrasion: • The wearing away of rock material by grinding • action • Exfoliation: • The peeling of surface layers from exposed • bedrock • Hydrolysis: • The chemical reaction of water with other • substances
Oxidation Oxidation of Desert Landscape
EROSION: • The removal and transport of materials by natural agents.
Transport Agents Wind Water Glaciers Gravity Volcanic Eruption
Types Mass Movement Erosion: (Mass Movement ) • Talus – rock fragments that have been weathered from a cliff and pulled down by gravity.
Types Mass Movement Erosion: (Mass Movement ) • Landslide – movement of a mass of bedrock or loose soil and rock down a slope of a hill, mountain, or cliff. • usually occurs on steep slopes after heavy rains or when large amounts of snow melt. • (makes soil heavier and can make a layer of water betweenthe soil and bedrock which makes the soil easier for gravity to pull down)
Types of Landslides: (Mass Movement Erosion) • Creep – slow, gradual movement of soil down a slope. • Objects fixed in the soil (fence) will also lean downhill. • The presence of water in soil contributes to creep.
Types of Landslides: (Mass Movement Erosion) • Slump - blocks of land tilt and move downhill along a surface that curves into the slope. • Usually occurs becausethe top of the slope istoo steep and the bottom can’t support it. Slump Animation
Types of Landslides: (Mass Movement Erosion) • Mudflow - rapid movement of water that contains large amounts of suspended clay and silts. • Can travel up to 100km/Hr • can move rock, boulders, trees, and houses • occurs in drier regions that get infrequent, but heavy rainfall
Types of Landslides: (Mass Movement Erosion) • Earthflow - mass of weathered material saturated with water flows downhill • Slower and less fluid than a mudflow. • speed depends on the amount of water in soil, composition of soil, and steepness of slope • can last a couple of days to years
Types of Landslides: (Mass Movement Erosion) • Lahar - mudflow that accompanies a volcanic eruption. • heat from the erupted material melts the snow on top of a volcano which and it moves down the side of the volcano.
Soil is a combination of highly weathered clastic sediments (mostly sand, silt and clay), chemical sediments and organic material in which plants can grow.
The material from which soil is formed is called Parent Material.
Soils formed from sediments that were produced elsewhere are called Transported Soils (Example: Glacial and Alluvial Soils)
A soil whose parent material is the bedrock beneath it is a Residual Soil
Residual Soils form as their parent material is weathered away. How fast this happens depends on four things:1. The rock type of the parent material (ex. some rocks are more chemically stable than others)2. Climate (high rainfall, hot temps. Increase rate of soil formation)3. Plant and Animal Activity (Biochemical and Biomechanical Weathering)4. Slope (A deep soil can’t form on a slope)
A cross-section of a soil, from the surface (A) to the un-weathered parent material (R) is called a Soil Profile. (A) (B) (C) (R)
Organic remains (Humus) Fine particles of weathered parent material mixed with Humus- Topsoil Clays, Iron Oxides and dissolved minerals that have leached From above- Subsoil, usually brown or red Partially weathered parent material- Rock Fragments Parent Rock- “Bedrock”
Conditions in which soils develop in different locations cause the profiles of soils to vary in appearance. What causes this variation is the composition, appearance and thickness of the 4 major layers or Horizons of a soil profile.
Examples of Soil Profiles from around the World (Different types of soils)