EARTH121 Chapter Notes - Chapter 14: Mass Wasting, Granular Material, Regolith
2 Sep 2016
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Mass wasting downslope movement of rock, regolith, soil under the direct influence of gravity. Distinct from weathering because it does not require a transporting medium. Once weathering weakens and breaks rock apart, mass wasting carries the debris downslope, where a stream, acting as a conveyor belt, carries it away. Earth"s mountain-building and volcanic processes produce many slopes, sporadically changing the elevations of landmasses and the ocean floor. Usually young mountains, which are rapidly eroded, more dramatic features. Gravity is the controlling force but ther are many factors. Trigger the last straw after slope is weakened. Heavy rains or periods of snowmelt saturate surface. When pores are filled, cohesion among particles is destroyed. Oversteepening slopes can be a trigger (stream or glacier undercutting valley, waves against base of a cliff, humans) Angle of repose steepest angle which unconsolidated granular material remains stable. Depends on size and shape of particles.
