Chapter 11 Weathering, Karst Landscapes, & Mass Movement Flashcards
Physical Weathering
Frost Wedging
Salt-Crystal Growth
Exfoliation
Root Wedging
Factors that influence weathering
- Rock Composition and Structure
- Climate (Precipitation and Temperature)
- Slope Orientation
- Subsurface Water
- Vegetation
Chemical Weathering
Spheroidal Weathering Hydration Hydrolysis Oxidation "Rusting" Dissolution of Carbonates
Solution Sinkhole
Forms due to gradual dissolution of
carbonate rock
- Depths of 7-330 feet; 33-3300 feet wide
Collapse Sinkhole
When a solution sinkhole collapses
through roof of underground cavern
- Develops over hours or days
- Common in Florida
Denudation
Any process that wears away or rearranges landforms
Bedrock
Solid, consolidated rock
Regolith
Rock fragments; broken up
Soil
Rock fragments and finer particles;
dirt; developed from parent material
Physical Weathering:
Frost Wedging
Water penetrates rock through pores (holes) and joints
- When water freezes, it expands; causes wedges in rock to break
Physical Weathering:
Salt-Crystal Growth
Water is easily evaporated in arid regions
- When water evaporates, salt is left behind in pores and joints
Physical Weathering:
Exfoliation
Rock peeling or slipping off in sheets
- Shedding of the outer layer
- Similar to losing outer layers of an onion
Physical Weathering:
Root Wedging
Roots create joints in rock; wedge them apart
Chemical Weathering:
Spheroidal Weathering
Causes the softening and rounding of rock
- Water penetrates rock joints and dissolves or cements weaker minerals
Chemical Weathering:
Hydration
Minerals combining with water
- Structural change; little chemical change
Chemical Weathering:
Hydrolysis
Decomposition of chemicals
with water reaction
Chemical Weathering:
Oxidation
“Burning” of metals in rock due to reactions with oxygen (rusting)
- Weakens bonds that holds minerals together
Chemical Weathering:
Dissolution of Carbonates
Weathering of rock with calcium carbonate by a weak acid
- Limestone common example
- Water vapor dissolves carbon dioxide
Geography of Weathering
More active in lower latitudes
- Heat, moisture, vegetation are abundant
• Frost action
- Occurs primarily in higher latitudes and elevations
• Salt Wedging
- Occurs primarily in arid regions
Mass Movement
Downslope movement of material
• Made up of soil, sediment, or rock
• Gravity and water are primary forces
• Short distance (up to a few miles)
Mass Movement:
Slope
An inclined surface that rock
material moves down
Mass Movement:
Conditions for Slope Failure
Saturation by heavy rainfall
Volcanic eruption melts ice and snow
Mass Movement:
Rockfall
Volume of rock that falls; hits surface
- Forms Talus Slope: Cone-shaped piles of broken rocks
Mass Movement:
Debris Avalanches
Mass of tumbling rock, debris, soil
- Ice and water move debris
- Danger from rapid speed
Mass Movement:
Earthflow
Movement of fine-grained material
- A scarp (cliff) created at top of hillside
Mass Movement:
Mudflow
Movement of very watery fine-grained rock material
- Flows like liquid
- Faster than earthflows
Mass Movement:
Soil Creep
Slowest of all mass movement
- Movement of soil/regolith overtime
- Soil particles lifted and disturbed
Mass Movement:
Landslide/Rockslide
Occur more rapidly than soil creeps and flows (within minutes)
- Occur on steep slopes
What type of physical weathering is limited to arid regions?
Salt Crystal Growth
