Week 4: Weathering, Erosion, Deposition, Flooding, and Flood Control

weathering

the gradual destruction of rock at the surface of the earth

transportation

the movement of material across the earth’s surface by water, ice, wind, or gravity

erosion

the name of the process of weathering and transportation

types of weathering

1. physical weathering

2. chemical weathering

physical weathering

process by which rocks are broken down into smaller pieces by external conditions, creating sediment

types of physical weathering

1. frost heaving and frost wedging

2. Exfoliation (pressure release)

3. Plant roots

4. Friction and impact

5. Burrowing of animals

6. Temperature changes (repeated thermal expansion and contraction)

7. Evaporite crystal growth (salt crystals)

Chemical weathering

The process that breaks down rock through chemical changes (corrosion), creating smaller particles (soil)

Agents of chemical weathering

1. Temperature

2. Pressure

3. Acceleration of reactions by catalysts (like water, oxygen, carbon dioxide, biological (living) organisms, or other chemicals like sulfur and chlorine)

types of sediment

1. saprolite

2. colluvium

3. alluvium

saprolite

A coating of bedrock or other earth materials at the surface, typically loose and unconsolidated. Typically has significantly lower strength parameters in the original parent material. like an outer skin of corroded material (because exposed and subject to chemical. weathering)

sediment formation due to: chemical weathering

transportation method: JK it hasn’t moved lol

distance traveled: forms in place (again hasn’t moved lol)

colluvium

sediment formation due to: physical weathering

transportation method: gravity?

distance traveled: from origin to base of slope

alluvium

sediment formation due to: physical weathering

transportation method: fluid action (usually water)

distance traveled: moved a significant distance

sediment load

the total amount of earth material being carried by a stream

types of sediment load

1. suspended load (silt and clay sized particles)

2. bed load (sand, gravel, cobble, and boulder sized particles)

3. dissolved load (ions carried in solution)

deposition

generalized areas of sediment accumulation (alluvium deposition)

what is the actual definition for deposition and does it apply only to alluvium since it is the only type of sediment that has traveled a long distance and has the opportunity to “accumulate”?

what is shoreline deposition? as mentioned in the videos, does that just mean: how do beaches form?

shoreline deposition process

1. sediment source provides deposition material

2. wave action redistributes the sediment

longshore current

medium in which shoreline. deposition migrates along the coast

longshore drift? is this the same as longshore current?