Earth’s Surface Erosion

Vocabulary Erosion- the process that wears down and carries away rocks and soil

Erosion Gravity acts as a force of erosion by causing a mass movement Mass movement- a process that moves sediment down a hill There are 4 ways a mass movement may occur

Mass Movement Landslide- a rapid movement of large amounts of rock and soil

Mass Movement Mudflow- a rapid downhill movement of a mixture of water, rock and soil

Mass Movement Slump- mass of rock and soil suddenly slips down a slope This is different from a landslide because it comes down in one large mass

Mass Movement Creep- a very slow movement of rock and soil Usually creeps cause objects to sit at unusual angles

Water Erosion Stream- a channel along which water continually flows River- a large stream usually forming from several streams flowing together

Features of Streams Flood Plain- a flat area along a stream that is entirely covered only during times of floods Meander- the winding and bending of a stream as it erodes the land Only older streams do this Oxbow Lake- when sediment builds up, cutting off the meander from the rest of the river, causing a separate, curved lake

Water Erosion Fast moving rivers that are straight and narrow cut steep slopes and create a V-shaped valley Example- Grand Canyon

Grand Canyon

Water Erosion Waterfall- a river cuts through soft rock faster than hard rock Example- Niagara Falls

Niagara Falls

Groundwater Erosion A form of chemical erosion Makes caves and sinkholes CAVE- limestone erodes away, leaving behind a dry narrow passage SINKHOLE- weakened limestone where the entire portion of the ground suddenly collapses

Glacial Erosion Glaciers erode land in 2 ways Plucking- as a glacier flows over land it picks up rocks Abrasion- gauges and scratches in rocks as a glacier drags across land Causes large, bowl shaped valleys called cirques Cuts U-shaped valleys in landforms May leave behind large, cold glacial lakes

Wind Erosion Deflation- wind picks up and carries away small particles The faster the wind, the larger the particles it can carry Example- Sand dunes