Weathering and Landforms Topics

Gravity Movements (Part 2)


• Rockfalls are rapid movements in which rock fragments fall through the air.  Rockfalls usually occur along steep slopes.  The rubble that piles up as a result of rock falls is called talus.  

Rockfall talus in Dickenson county (photograph by Robert Whisonant)

MapThis Dickenson County talus pile (above photo) has collected the material that has fallen from the road cut above it.  Rocks detach and fall along bedding planes and joint surfaces.



• Creep is the very slow downslope movement of soil and rock fragments by gravity. 

Bent tree trunks
Evidence of creep as seen by the curved trees in Rockbridge County (photograph by Stan Johnson)

MapTrees that are curved at their bases indicate the occurrence of creep on this Rockbridge County slope.  As loose surface material carries the base of the tree downhill, the upper part of the tree grows straight toward sunlight, creating the curvature.