Weathering and Erosion Chapter 5

Gravity Agents of Erosion are mostly caused by Gravity.

Streams/Rivers Erodes sediment upstream. Carries it along the stream. Can be “deposited” many times, or carried the entire way. This rounds out the pieces of sediment. Young rivers move quickly, and cut INTO the bedrock. Called downcutting.

Rivers In plains, the rivers will create meanders. As it approaches the end, it slows down. It heads toward the ocean. Slows down, and loses energy, so it drops the sediment. Creates deltas.

Glaciers Move due to gravity. Can cut grooves into bedrock. Depositional landforms formed by glaciers: Moraines, till, drumlins, outwash plains, stratified drift, and kettles. Till – sediment specifically from glaciers

Till

Moraine

Kettles

Outwash plains

Ocean Waves Erodes rock by hitting it over and over again. Beach is formed from deposition. If waves approach at an angle, it can create a longshore current. Sediment will be dropped parallel to the shore. This process is called longshore drift Spits and barrier islands will result.

Spits

Barrier Islands

Wind Erosion- Yardangs

Wind Erosion - Dunes

Mass Wasting Earth materials moving downhill. Gravity causes this. Some move quickly. Others slowly Some dry and some wet. Mudslides, rockfalls, avalanches, soil creep

Mass Wasting

Mudslide

Soil Creep

Landforms

Coastlines Forms boundaries between land and large body of water. Formed by: deposition of sand or silt, but can be eroded away as well. Along stable coastlines, deposition and erosion happen at a steady pace.

Dunes Hill of sand built up by deposition by wind or water.

Mountains Formed by two tectonic plates colliding with one another (generally) Also by lava building up.

Glaciers Large body of snow and ice Forms on land and does not melt each year. Snow is compacted into ice, gets larger and heavier. DIGS into earths surface as it moves.

Delta Formed at the mouth of the river. Deposition of sediment as the energy slows down.

Lakes Relatively still body of water that is somewhat large. Usually fresh water – especially when next to landforms that carry snow or glaciers.

Peninsula Surrounded by water on three sides.

Isthmuses Narrow strip of land connecting two other bodies of land. North America and South America are connected by Panama.

Canyon Deep channels worn into the ground by running water.

Plateaus High, flat regions of land often have steep sides.

Plains Large flat areas. Formed by rivers that change course or flood frequently, wearing away taller land features.