CHAPTER 15 Focus Points

• Physical weathering: Rates of physical weathering are greatest at high elevations and high latitudes.

• Frost wedging: Frost wedging is the most important type of physical weathering where temperatures fall below freezing.

• Chemical weathering: Chemical weathering is dominant where temperatures remain above freezing and there is plenty of moisture.

• Karst processes: Carbonate rocks dissolve in naturally acidic rainwater, forming karst topography. Most karst topography is found in limestone bedrock.

• Surface karst topography: Limestone pavement, sinkholes, collapse sinkholes, disappearing streams, cockpit karst, and tower karst are among the most prominent surface features in karst topography.

• Subterranean karst: Subterranean landforms, such as caverns and speleothems, are common in karst regions.

• Causes of mass movement: When the downslope force exceeds the resistance force, a slope will fail, and mass movement will occur. Many factors, such as earthquakes, heavy rains, and roadcuts, can trigger mass movement events.

• Mass movement speed: Material moves downslope at speeds ranging from slow soil creep to rapid and deadly avalanches and rockfall.

• Human toll: Many human fatalities caused by landslides occur because people live on steep and unstable slopes that have been weakened by heavy rains.