GEL 25 Lecture Notes - Lecture 17: Rockfall, Half Dome
Document Summary
Drained by westward-flowing tuolumne and merced rivers. Jointing: water infiltrates cracks in rocks and freezes, expanding fractures. Makes the granite susceptible to weathering and erosion. Permits infiltration of water into the body of rock. Planar joints and exfoliation creates planes of weakness in rocks that makes them susceptible to weathering and erosion. Weakening of rock faces along joint planes generates rockfalls. Occurs as a mass of free-falls bounces down the side of cliffs and exploding at base. Angular block of talus derived from a prehistoric rockfall. Rockfalls may be triggered by intense rainfalls or earthquakes.
