GL102 Chapter Notes - Chapter 14: Earthflow, Solifluction, Frank Slide
Document Summary
Mass wasting is downslope movement of rock, regolith, and soil directly from gravity. Distinct from erosional processes because it does not require a transporting medium such as water, wind or glacial ice. Once weathering weakens and breaks the rock, mass wasting carries debris downslope. Combined effects of mass wasting and running water produce stream valleys. If streams alone produced valleys, the valleys would be very narrow. Most rapid events occur in areas of rugged, geologically young mountains. As mountain building subsides, mass wasting and erosion lower the land. As a landscape ages, less dramatic downslope movements occur. Trigger is not the sole cause; it is the last straw . May occur from heavy rainfall or snowmelt. Water adds weight to the sediment and gravity pulls it downward. Unconsolidated granular particles assume a stable slope: angle of repose. Varies from 25 degrees - 40 degrees. Larger, more angular particles maintain steeper slopes. Fig 14. 4 - effect of water on mass wasting.
