Ch. 11 Weathering

Study of the origin, evolution, shape and spatial distribution of landforms

Process that wears away or rearranges landforms through the action of moving water, waves, wind, ice or gravitational forces

• Landscapes undergo initial uplift followed by erosion and removal of earth materials that eventually reduces slope angles
• suggests that all regions eventually evolve from young rugged landscapes into old erosional landscapes with subdued topography

Forces such as friction, cohesion and gravity, inertia are balanced

shear forces unbalanced

The point at which shear stress overcomes shear strength

increase shear stress or decrease shear strength

Destabilizing events (uplift and earthquake)

(Rainfall, deforestation, road construction)

Potential energy of position, heat energy from sun, kinetic energy, chemical energy from earth's interior

Involves the downward movement of materials on slopes under the driving influence of gravity

• Fall
• slide
• flow 
• creep

• Speed
• size 
• motion

occur when a piece of rock on a steep slope becomes dislodged and subsequently falls down the slope

Shallow landslides that travel down-slope as muddy slurries

tends to be slower, carry a larger percentage of earth materials, and are also more highly water-saturated

The slowest debris  flow, driest form of debris flow that occurs when wet ground breaks up and flows down-slope

A persistant mass movement of surface material

periods of wet and dry weather or thermal heating that produces soil expansion

occurs in cold regions where the upper few feet of regolith becomes waterlogged during the summer

Human-induced mass movements

Weathering can produce individual mineral particles

weathering that causes mineral particles to dissolve in water

Loose broken rock at the surface formed by weathering and transportation processes

Parent material from which regolith and soil develops

Form as water containing dissolved carbonates slowly drips from cave ceilings

Form by growing down from the ceiling of caves

Form by building up from the cave floor

Produced when stalactites and stalagmites meet